Ministère de l’Enseignement Supérieur et de la Recherche ...acrylonitrile-butadiene-styrene (ABS). These blends are tough and have good processability. One of the most interesting

Ministegravere de lrsquoEnseignement Supeacuterieur et de la Recherche Scientifique

Universiteacute dOran

Faculteacute des Sciences

THEgraveSE DE DOCTORAT DETAT

Option Chimie Physique

Preacutesenteacutee par

LEBSIR Hayet neacutee BENDAIKHA

Intituleacutee

SYNTHESIS AND CHARACTERIZATION OF POLY (1 3 DIOXOLANE) AND ITS COPOLYMERS

STUDY OF THEIR COMPATIBILIZING EFFECT ON IMMISCIBLE BLENDS

Membres du Jury

Nom Preacutenom Grade Etablissement drsquoOrigine Qualiteacute

Krallafa Abdelghani Pr Universiteacute drsquoOran Preacutesident

Hacini Salih Pr Universiteacute drsquoOran Examinateur

Benachour Djafer Pr Universiteacute de Seacutetif Examinateur

Belhakem Mustapha Pr Universiteacute de Mostaganem Examinateur

Ould Kada Seghier Pr Universiteacute drsquoOran Directeur de Thegravese

Acknowledgements

I would like to thank my advisor Prof S OULD KADA for his help and to

express my sincere gratitude to Prof A KRALLAFA for providing continuous support

to this work His expertise guidance and understanding were a significant help

throughout my work

Very special thanks are extended to Prof Jeanne FRANCOIS for allowing me

to use instruments in her laboratory and for numerous discussions suggestions and

valuable advices which were important contribution to this research

Special thanks and deep appreciation go to Mr G CLISSON for his patience

and help with SEC and DSC measurements

I also owe my sincere appreciation to Mr A KHOUKH for his help with NMR

measurements and important comments considering NMR spectra

I want to thank gratefully Prof M BELBACHIR and Dr A TAYEB for

support and help to this work

I also owe my thanks to Prof Z BOUTIBA and Miss A HADJ BRAHIM for

optical microscopy measurements

I also owe my thanks to Dr MHAMHA and Miss S CHAOUI for Rheological

measurements

To Mr YOUSFI (ENPC-Chlef) I want to thank for Polymer supply

I acknowledge Prof S HACINI Prof D BENACHOUR and Prof M

BELHAKEM who honored me in participating in the jury of my thesis

Special gratitude to my husband FOUAD for being a continuous source of

encouragements For that I doubt I will ever be able to convey my appreciation fully

Special Thanks are also given to my mother father sisters and daughters for

moral support

TABLE OF CONTENTS ACKNOWLEDGEMENTS i SUMMARY hellipii

CHAPTER I LITERATURE REVIEW helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 1

11 Macromonomer Interest and Synthesis helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 2

12 Ring-Opening Polymerization Overview helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 4

121 Polymerizability of Cyclic Compounds helliphelliphelliphelliphelliphelliphelliphelliphellip 4

122 Mechanisms of Ring-opening Polymerization helliphelliphelliphelliphelliphellip 6

123 Cationic Ring-Opening Polymerization of Heterocycles helliphellip 7

13 Cationic polymerization of cyclic acetals helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 9

14 Synthesis of functionalized poly (13-dioxolane) helliphelliphelliphelliphelliphelliphelliphelliphelliphellip 13

141 Reaction of 1 3-dioxolane and hydroxyl-containing compounds 13

142 Synthesis of Poly (13-dioxolane) macromonomers helliphelliphelliphellip 15

15 Amphiphilic Graft Copolymers helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 16

151 Graft Copolymers helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 16

152 Amphiphilic Copolymers helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 20

16 Kinetics of Free Radical Polymerization helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 22

161 Kinetics of free radical addition Homo and Copolymerization 22

17 Chain Growth Copolymerization helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 31

171 Copolymerization Equations helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 31

172 Determination of Reactivity Ratios helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 37 18 Controlled Radical Polymerization helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 42

181 Fundamentals of ControlledLiving

Radical Polymerization (CRP) helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 43

182 Typical Features of ATRP helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 44

183 Controlled Compositions by ATRP helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 46

References helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 49

CHAPTER II Synthesis and Characterization of Macromonomers 54

21 Introduction helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 54

22 Experimental helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 55

221 Chemicals and Purification helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 55

222 Synthesis of Poly (13-dioxolane) Macromonomers helliphelliphelliphellip 57

223 Synthesis of Poly (13-dioxolane) Hydrogel Network helliphelliphellip 57

23 Characterization Techniques helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 57

231 Raman Spectroscopy helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 57

232 1H-NMR Spectroscopy helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 58

233 Size Exclusion Chromatography helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 58

234 Swelling Measurements helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 58

235 Rheological Measurements helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 59

24 Results and Discussion helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 59

241 Structural Characterization of Macromonomers helliphelliphelliphelliphellip 59

242 Molecular Weight Determination helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 62

243 Swelling of Poly (13 Dioxolane) Hydrogel helliphelliphelliphelliphelliphelliphellip 63

244 Viscoelastic Behavior helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 64

Conclusion helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 67

References helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 68

CHAPTER III Synthesis and Characterization of Copolymers 69

322 Synthesis of Poly (Styrene-g-Poly (1 3-dioxolane)) helliphelliphelliphellip 71

323 Synthesis of Poly (Methyl Methacrylate-g-Poly (1 3-dioxolane))76

33 Characterization Techniques helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 76

331 1H-NMR Spectroscopy helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 76

333 Diffraction Scanning Calorimetry helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 77

341 Structural Characterization of the Copolymers helliphelliphelliphelliphellip 78

342 Molecular Weight Determination and Copolymer Composition 80

343 Determination of Monomer Reactivity Ratios helliphelliphelliphelliphelliphellip 84

344 Glass Transition Temperatures helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 89

CHAPTER IV Compatibilization Effect of Poly (Styrene-g-Poly (1 3 Dioxolane)) on Immiscible Polymer Blends of Polystyrene and Poly (Ethylene Glycol)

41 Background helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 95

411 Physical Blends helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 95

412 Equilibrium Phase Behavior helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 95

413 Compatibilization helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 97

414 Incorporation of Copolymers for Compatibilization helliphelliphellip 98

415 The Effect of Compatibilizer on a Blend helliphelliphelliphelliphelliphelliphelliphellip 99

416 Methods of Blend Preparation helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 100

421 Materials helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 102

422 Blend Preparation helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 102

43 Characterization Techniques for Compatibilization helliphelliphelliphelliphelliphelliphelliphellip 102

431 Dilute Solution Viscometric Measurements helliphelliphelliphelliphelliphelliphellip 102

432 Optical Microscopy helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 103

433 FTIR Analysis helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 103

441 Characterization of the Homopolymers helliphelliphelliphelliphelliphelliphelliphellip 104

442 Study of Compatibilization by Dilute Solution Viscometry hellip 106

443 Optical Microscopy and Phase Morphology helliphelliphelliphelliphelliphelliphellip 116

Conclusions helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 124

References helliphelliphelliphelliphelliphellip helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 125

CHAPTER V Compatibilization Effect of Poly (Methyl Methacrylate-g- Poly (1 3 Dioxolane)) on Immiscible Polymer Blends of Polystyrene and Poly (Ethylene Glycol)

522 Blend Preparation helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 128

531 Dilute Solution Viscometry helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 128

541 Characterization of the Homopolymers helliphelliphelliphelliphelliphelliphelliphelliphellip 129

References helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 145 CONCLUSIONS helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 146

SUMMARY

Research and development performed on synthetic polymers during the last century has led to

many classes of different polymers for specific applications New types of synthetic polymers

with tailor-made properties are still being introduced for new applications The challenge for

polymer chemists is to control and alter the polymerization conditions such that the final

product has a well-defined structure with desired properties The complex structure of

polymers requires continued analytical chemical efforts to understand the polymerisation

process and the relationships between the molecular structure and material properties

The central point of this thesis is the synthesis and the exploration of the benefits of graft

copolymers derived from poly (1 3 dioxolane) (PDXL) as compatibilizing agents via their

incorporation in immiscible polymer blends The enhancement of adhesion in the solid state

can be accomplished by introducing a compatibilizer that can act as an adhesive between two

polymers andor by control of morphology especially by inducing the phase co-continuity

Graft copolymers offer all Properties of block copolymers but are usually easier to synthesize

Moreover the branched structure offers important possibilities of rheological control i e it

leads to decreased melt viscosities which is an important advantage for processing Depending

on the nature of their backbone and side chains they can be used for a wide variety of

applications such as impact-resistant plastics thermoplastic elastomers polymeric

emulsifiers and even more exciting is the ability of these graft copolymers to function as

compatibilizersinterfacial agents to blends immiscible polymers

The state-of-the-art technique to synthesize graft copolymers is the copolymerization of

macromonomers with low molecular weight comonomers It allows the control of the

polymeric structure which is given by three parameters (i) chains length of the side chains

which can be controlled by the synthesis of macromonomers by living polymerization (ii)

chain length of the backbone which can be controlled in a living polymerization (iii) average

spacing of the side chains which is determined by the molar ratio of the comonomers and the

reactivity ratio of the low-molecular-weight monomer

New properties lower prices and reuse of polymers are needed to meet demands of todayrsquos

society and hence of the polymer industry Unfortunately the demands for many applications

need a set of properties that no polymers can fulfil One method to satisfy these demands is by

mixing two or more polymers Materials made from two polymers mixed are called blends In

recent years blending of polymers as a means of combining the useful properties of different

materials to meet new market applications with minimum development cost offers an

interesting route to improve a variety of specific properties of the thermoplastics This has

been increasingly used by the polymer industry

Much work has been done on the blending (mixing) of polymers by many authors A large

part of these studies deal with attempts to obtain a combination of properties of different

polymers Unfortunately these properties of the polymer blends are usually worse instead of

better for many combinations of polymers Significance for these properties is compatibility

between the different polymers which is frequently defined as miscibility on a molecular scale

of the blends components The incorporation of a dispersed phase into a matrix mostly leads

to the presence of stress concentrations and weak interfaces arising from poor mechanical

coupling between phases and therefore morphologies with coarseness commonly on

micrometer scale are obtained Improving mechanical and morphological properties of an

immiscible blend is often done by compatibilization which is a process of modification of the

interfacial properties in immiscible polymer blend resulting in reduction of the interfacial

tension coefficient formation and stabilisation of the desired morphology The use of graft or

block copolymers as compatibilizers for immiscible polymer blends has become an efficient

means for development of new high-performance polymer materials There have been

numerous techniques of studying the miscibility of the polymeric blends The most useful

techniques are viscosimetry measurementsiiiiii thermal analysisiv dynamic mechanical

analysisv refractive indexvi nuclear magnetic resonance methodvii scanning electronviii and

optical spectroscopyix

i Z Sun W Wang and Z Fung Eur Polym J 28 (1992) 1259 ii Aroguz AZ and Baysal BM Eur Polym J42 3 (2006) 11ndash5iii Zhang Y Qian J Ke Z Zhu X Bi H and Nie K Eur Polym J 38 (2002) 333ndash7 iv M Song and F Long Eur Polym J 27 (1991) 983 v Olabisi O Rebeson LM and Shaw MT Polymerndashpolymer miscibility New York Academic Press (1979) vi AV Rajulu RL Reddy SM Raghavendra and SA Ahmed Eur Polym J 35 (6) (1999) 1183 vii EG Crispim ITA Schuquel AF Rubira and EC Muniz Polymer 41 (3) (2000) 933 viii Martin IG Roleister KH Rosenau R and Koningsveld RJ Polym Sci Part B Polym Phys24 (1986) 723 ix W Wu X Luo D Ma Eur Polym J 35 (1999) 985

Well-known examples of commercial blends are high impact polystyrene (HIPS) and

acrylonitrile-butadiene-styrene (ABS) These blends are tough and have good processability

One of the most interesting examples of an amorphous polymer is polystyrene because of its

brittleness Adding a compatibilizer with the structure of a copolymer to

Polystyrenepolyethylene (PSPE) improves the toughness by a factor 3x Another example is

the use of poly (styrene-co-methacrylic acid) as a compatibilizer in immiscible (incompatible)

blends of PS and polyethylene (PEG)xi

It is of great interest to study miscibility and phase behaviour of two different commodity

immiscible polymer blend systems as PSPEG and polymethyl methacrylate polyethylene

glycol (PMMAPEG) by adding poly (styrene-g-PDXL) and poly (methyl methacrylate-

PDXL) copolymers as compatibilizers respectively Firstly these systems consist of a very

rigid amorphous component (styrene andor PMMA) and a very flexible low-melting point

PEG The extremely high difference of glass transition temperatures (Tg) between the

components motivates us to investigate the phase behaviour of the blends via

compatibilization with prepared grafted copolymers

The first part of the thesis is devoted to the synthesis and characterization of amphiphilic graft

copolymers which were prepared in solution by radical polymerization of hydrophilic poly (1

3 dioxolane) macromonomers as side chains and hydrophobic comonomers such as styrene

and methyl methacrylate as backbone The second part of the thesis describes the blends

preparation and the study of the compatibilization effect of the incorporated amphiphilic graft

copolymers on immiscible (incompatible) blends

The research work in this thesis is presented through several chapters described as follows

Chapter I is a bibliographic survey on polymerization reactions involved in the thesis

Literature concerning the poly (1 3 dioxolane) was included

Chapter II describes the synthesis of poly (1 3 dioxolane) macromonomers and their

characterization As an aside research poly (1 3 dioxolane) network was obtained and the

x E Kroeze thesisUniversity of Groningen (1997) xi Norimasa Watanabe Isamu Akiba and Saburo Akiyama Europ Polym Journal 37 (2001) 1837-1842

swelling and rheological behaviours of this network were discussed and included in this

chapter

Chapter III deals with the synthesis of a series of amphiphilic graft copolymers based on

polystyrene and methyl methacrylate as backbone with poly (1 3 dioxolane) macromonomers

as grafts in this study Selection of proper reaction conditions in terms of overall monomer

concentration and monomer molar ratio were investigated in order to prevent crosslinking

reactions due to the presence of bis-functional poly (1 3 dioxolane) macromonomers

The structure and composition of the graft copolymers were determined by Size Exclusion

Chromatography (SEC) technique and Proton Nuclear Magnetic Resonance (1H-NMR)

analysis Also Modulated Temperature Differential Scanning Calorimeter (MTDSC) was used

for thermal analysis to study the influence of poly (1 3 dioxolane) content on the glass

transition temperature of the copolymers

Last but not the least Chapter IV and Chapter V deal with the most important part of the

thesis which is the study of the compatibilization effect of the prepared copolymers

incorporated in two different immiscible blend systems These two chapters describe first

the polymers used as blend components and also polyblends preparation was discussed The

phase behavior and compatibilization of these polyblends were studied at a composition

of 5050 for both PSPEG and PMMAPEG systems Various amounts of copolymers were

incorporated to the so-called blends for compatibilization The techniques used for this study

were optical microscopy (OM) to analyze their morphology and Fourier-Transform Infra-Red

(FTIR) spectroscopy used to detect the intermolecular interactions in the blends In addition

viscometric method which is a simple inexpensive and sensitive analytical technique and also

alternative to other methods was used The application of the dilute-solution viscosity (DSV)

method for the study of interactions and miscibility of the polymeric system has been

described in more details in these chapters

Conclusions have been made on copolymer characterizations in terms of mostly monomer

reactivity and indeed on compatibilizing effect of these copolymers on the selected polymer

blends This study provides interesting results which can be useful for the development

nanoporous materials

REacuteSUMEacute

La recherche et le deacuteveloppement faits sur des polymegraveres syntheacutetiques pendant le dernier siegravecle

ont abouti agrave plusieurs types de polymegraveres pour des applications speacutecifiques Les nouveaux

polymegraveres syntheacutetiques avec des proprieacuteteacutes faites sur mesure sont toujours introduits pour de

nouvelles applications Le deacutefi pour les chimistes en polymegraveres est de controcircler et drsquoalteacuterer les

conditions de polymeacuterisation de telle sorte que le produit final ait une structure bien deacutefinie avec

des proprieacuteteacutes souhaiteacutees La structure complexe de polymegraveres exige des efforts continus en

chimie analytique pour comprendre le processus de polymeacuterisation et les relations entre la

structure moleacuteculaire et les proprieacuteteacutes des mateacuteriaux

Le centre drsquointeacuterecirct de cette thegravese est la synthegravese et lexploration des avantages des copolymegraveres

greffeacutes deacuteriveacutes agrave partir du poly (1 3 dioxolane) (PDXL) utiliseacutes comme agents compatibilisant

via leur incorporation dans des meacutelanges de polymegraveres non miscibles Lrsquoameacutelioration drsquoadheacutesion

agrave lrsquoeacutetat solide peut ecirctre accomplie en introduisant un compatibilisant qui peut agir comme un

adheacutesif entre deux polymegraveres et ou par le controcircle de la morphologie particuliegraverement en

incitant la co-continuiteacute des phases Les copolymegraveres greffeacutes offrent toutes les proprieacuteteacutes des

copolymegraveres en blocs mais sont toujours plus facile agrave syntheacutetiser De plus la structure ramifieacutee

offre des possibiliteacutes importantes dans le controcircle rheacuteologique cest-agrave-dire elle aide la

diminution de la viscositeacute qui est un avantage important pour la transformation Selon la nature

de la chaicircne principale et des chaicircnes lateacuterales ces copolymegraveres peuvent ecirctre employeacutes pour une

grande varieacuteteacute drsquoapplications comme plastiques reacutesistants au choc elastomers thermoplastiques

des polymegraveres eacutemulsifiants et mecircme plus inteacuteressant est la possibiliteacute de ces copolymegraveres greffeacutes

de fonctionner comme compatibilisant agents drsquointerface aux meacutelanges des polymegraveres non

miscibles

La technique la plus sophistiqueacutee pour syntheacutetiser les copolymegraveres greffeacutes est la

copolymeacuterisation de macromonomegraveres avec des comonomegraveres agrave faible masse moleacuteculaire Elle

permet le controcircle de la structure polymeacuterique par trois paramegravetres (i) la longueur des chaicircnes

lateacuterales qui peut ecirctre controcircleacutee par la synthegravese de macromonomegraveres par la polymeacuterisation

vivante (ii) la longueur de chaicircne principale qui peut ecirctre controcircleacutee dans une polymeacuterisation

vivante (iii) espacement moyen des chaicircnes lateacuterales qui est deacutetermineacute par le rapport molaire des

comonomegraveres et taux de reacuteactiviteacute du monomegravere agrave faible masse moleacuteculaire

De nouvelles proprieacuteteacutes des prix bas et la reacuteutilisation de polymegraveres sont neacutecessaires pour

reacutepondre aux demandes de la socieacuteteacute daujourdhui et agrave lindustrie de polymegraveres

Malheureusement ces demandes pour un grand nombre drsquoapplications ont besoin dun jeu de

proprieacuteteacutes quaucun polymegravere ne peut accomplir Une meacutethode de satisfaire ces demandes est en

meacutelangeant deux polymegraveres ou plus Les mateacuteriaux obtenus agrave partir de meacutelanges de deux

polymegraveres meacutelangeacutes sont appeleacutes meacutelanges (Blends) Ces derniegraveres anneacutees le meacutelange de

polymegraveres comme moyen de combiner les proprieacuteteacutes utiles de diffeacuterents mateacuteriaux pour

rencontrer un marcheacute de nouvelles applications agrave un coucirct minimal offre un itineacuteraire inteacuteressant

pour ameacuteliorer une varieacuteteacute des proprieacuteteacutes speacutecifiques des polymegraveres thermoplastiques Cela a eacuteteacute

de plus en plus employeacute par lindustrie des polymegraveres

Beaucoup de travaux ont eacuteteacute faits par plusieurs auteurs sur le meacutelange de polymegraveres Une grande

partie de ces eacutetudes sont dirigeacutees pour obtenir une combinaison des proprieacuteteacutes de diffeacuterents

polymegraveres Malheureusement ces proprieacuteteacutes des meacutelanges de polymegravere sont souvent plus

mauvaises que preacutevues pour la plupart des combinaisons de polymegraveres La signification de ces

proprieacuteteacutes est la compatibiliteacute entre les diffeacuterents polymegraveres qui est freacutequemment deacutefinie comme

la miscibiliteacute agrave lrsquoeacutechelle moleacuteculaire des composants du meacutelange Lincorporation dune phase

disperseacutee dans une matrice provoque surtout la preacutesence de contraintes et des interfaces faibles

qui reacutesultent du faible meacutelange meacutecanique entre les deux phases Lameacutelioration des proprieacuteteacutes

meacutecaniques et morphologiques dun meacutelange non miscible est souvent faite par compatibilisation

qui est un processus de modification des proprieacuteteacutes superficielle dans les meacutelanges de polymegraveres

non miscibles aboutissant agrave la reacuteduction du coefficient de tension superficielle la formation et

stabiliteacute de la morphologie deacutesireacutee Lutilisation des copolymegraveres greffeacutes ou agrave blocs comme

compatibilisant pour des meacutelanges de polymegraveres non miscibles est devenue un moyen efficace

pour le deacuteveloppement de nouveaux mateacuteriaux plus performant Il y a eu de nombreuses

techniques pour lrsquoeacutetude de la miscibiliteacute des meacutelanges polymeacuteriques Les techniques les plus

utiles sont les mesures viscomeacutetriques analyses thermiques analyses meacutecaniques indice de

reacutefraction la reacutesonance magneacutetique nucleacuteaire microscopes optique et eacutelectroniques agrave balayage

Les exemples de meacutelanges commerciaux tregraves bien connus sont le polystyregravene choc (HIPS) et

acrylonitrile-butadiene-styrene (ABS) Ces meacutelanges sont durs et ont bon processability Un

exemple de polymegraveres amorphes le plus inteacuteressant est le polystyregravene agrave cause de sa fragiliteacute

Laddition dun compatibilisant ayant la structure dun copolymegravere au meacutelange de Polystyregravene

polyeacutethylegravene (PSPE) ameacuteliore la dureteacute par un facteur de 3 Un autre exemple est lutilisation du

poly (styrene-co-acide meacutethacrylique) comme compatibilisant dans les meacutelanges non miscibles

de PS et le poly (eacutethylegravene glycol)

Il est tregraves important drsquoeacutetudier la miscibiliteacute et le comportement des phases de deux diffeacuterents

meacutelanges de polymegraveres commerciaux non miscibles (incompatibles) comme le

polystyregravenepolyeacutethylegravene glycol (PSPEG) et le polymeacutethacrylate de meacutethylepolyeacutethylegravene glycol

(PMMAPEG) en incorporant des copolymegraveres tels que (styrene-g-PDXL) et de (meacutethacrylate de

meacutethyle-PDXL) comme compatibilisant respectivement Premiegraverement lrsquoun des composants de

ces systegravemes est amorphe et tregraves rigide (le styregravene etou PMMA) et lrsquoautre (PEG) est flexible et

mou ayant un point de fusion tregraves faible Vu lrsquoextrecircme eacutecart entre les deux tempeacuteratures de

transition vitreuse (Tg) des composants de ces meacutelanges cela nous a motiveacute pour eacutetudier le

comportement de ces meacutelanges via compatibilisation avec des copolymegraveres greffeacutes preacutepareacutes par

nous mecircme

La premiegravere partie de la thegravese est consacreacute agrave la synthegravese et agrave la caracteacuterisation de copolymegraveres

greffeacutes amphiphiles preacutepareacutes en solution par la polymeacuterisation radicale des macromonomers

(poly (1 3 dioxolane)) hydrophiles comme des chaicircnes lateacuterales (greffons) avec des

comonomegraveres hydrophobes comme le styregravene et le meacutethyle methacrylate comme chaicircne

principale La deuxiegraveme partie de la thegravese couvre la preacuteparation des meacutelanges et leacutetude de leffet

de compatibilisant des copolymegraveres greffeacutes amphiphiles sur les meacutelanges non miscibles

(incompatibles)

La recherche concernant cette thegravese est preacutesenteacute par plusieurs chapitres deacutecrits comme suit

Le chapitre I est une recherche bibliographique sur les reacuteactions de polymeacuterisations impliqueacutees

dans la thegravese La Litteacuterature concernant le poly (1 3 dioxolane) est inclue

Le chapitre II deacutecrit la synthegravese des macromonomegraveres du poly (1 3 dioxolane) et leurs

caracteacuterisations Une recherche suppleacutementaire a eacuteteacute effectueacutee concernant la synthegravese drsquoun reacuteseau

tridimensionnel du poly (1 3 dioxolane) Une eacutetude sur les comportements gonflant et

rheacuteologique de ce reacuteseau ont eacuteteacute discuteacutes et inclus dans ce chapitre

Le chapitre III preacutesente la synthegravese dune seacuterie de copolymegraveres greffeacutes amphiphiles constitueacutes de

polystyregravene ou methacrylate de meacutethyle comme chaicircne principale et de macromonomers du poly

(1 3 dioxolane) comme greffons dans cette eacutetude Le choix de conditions de reacuteaction approprieacutees

en termes de concentration totale et le rapport molaire des monomegraveres ont eacuteteacute bien eacutetudieacutes pour

empecirccher les reacuteactions de reacuteticulation agrave cause de la preacutesence de macromonomegraveres bis-

fonctionnel de poly (1 3 dioxolane)

La structure et la composition des copolymegraveres greffeacutes ont eacuteteacute deacutetermineacutees par la technique de la

Chromatographie dExclusion steacuterique (CES) et la spectroscopie en Reacutesonance Magneacutetique

Nucleacuteaire de Proton (1H-NMR) Aussi la Calorimeacutetrie Diffeacuterentielle agrave balayage agrave Temperature

Moduleacutee Calorimeacutetrie (MTDSC) a eacuteteacute employeacute pour lanalyse thermique et pour eacutetudier

linfluence de la proportion du poly (1 3 dioxolane) dans les copolymegraveres sur leur tempeacuterature

de transition vitreuse

Derniers mais pas le moindre les deux Chapitre IV et le Chapitre V couvrent la partie la plus

importante de la thegravese qui est leacutetude de leffet de compatibilisant de ces copolymegraveres preacutepareacutes et

incorporeacutes dans deux diffeacuterents systegravemes de meacutelanges non miscibles (incompatibles) Ces deux

chapitres deacutecrivent dabord les polymegraveres employeacutes comme composants des meacutelanges agrave eacutetudier et

aussi la preacuteparation de ces meacutelanges a eacuteteacute deacutecrite Le comportement de phase et la

compatibilisation des meacutelanges de PSPEG et PMMAPEG agrave une composition de 5050 Des

quantiteacutes diffeacuterentes de copolymegraveres ont eacuteteacute incorporeacutees aux meacutelanges Les techniques

employeacutees pour cette eacutetude sont la microscopie optique (OM) pour analyser leur morphologie et

la spectroscopie agrave Transformeacutee de Fourier Infrarouge (FTIR) pour deacutetecter les interactions

intermoleacuteculaires dans les meacutelanges De plus la meacutethode viscomeacutetrique qui est une technique

simple peu coucircteuse et tregraves sensible a eacuteteacute employeacutee Lrsquoutilisation de la meacutethode de la viscositeacute de

solution dilueacutee (DSV) pour leacutetude dinteractions et la miscibiliteacute du systegraveme polymegravere a eacuteteacute

deacutecrite plus en deacutetail dans ces chapitres

Les conclusions ont eacuteteacute faites sur la caracteacuterisation des copolymegraveres en termes de surtout de la

reacuteactiviteacute des monomegraveres et bien entendu sur leffet compatibilisant de ces copolymegraveres sur les

meacutelanges de polymegraveres qui ont choisis Cette eacutetude fournit des reacutesultats inteacuteressants qui peuvent

ecirctre utiles pour le deacuteveloppement des mateacuteriaux nanoporeux

CHAPTER I Literature Review

11 Macromonomer Interest and Synthesis

Macromonomers bearing polymerizable end groups have received considerable interest

during the last two decades and become a useful tool for the preparation of a variety of graft

copolymers with well-defined structure and composition and polymer networks The

macromonomer method for preparing graft copolymers consists of preparing branches first

followed by the preparation of the grafted structure through the addition of the comonomer to

the macromonomer branch1 2

Therefore macromonomers become the side chains in the graft copolymer with well-defined

length and molecular weight As a sequence the molecular structure of the copolymer can be

determined depending on the amount of macromonomer incorporated and the reactivity of the

end groups

Macromonomers which are linear macromolecules carrying polymerizable functions at one or

two chain ends have been prepared by all polymerization mechanisms anionic cationic free-

radical polyaddition and polycondensation while the polymerizable end groups have been

introduced during the initiation termination or chain transfer steps or by modification of end

groups of telechelic oligomers3

Among the polymerization mechanisms mentioned above the ionic ones allow the best

control of molecular weight polydispersity and functionality of the macromonomers

However they require very demanding experimental conditions like high purity of monomers

and solvents complete absence of moisture and other acidic impurities inert atmosphere etc

Whereas free-radical methods which involve less severe working conditions are largely

used even though the control over the properties of the macromonomers is lower3 For

instance polymers of epoxides tetrahydofuran and cyclic siloxanes are commercially

produced by cationic ring-opening polymerization The history of ring-opening

polymerization of cyclic monomers is shorter than that of the vinyl polymerization and

1 G Carrot J Hilborn and DM Knauss Polymer 38 26 (1997) 6401-6407 2 P Rempp and E Franta Adv Polym Sci 58 1 (1984) 3 M Teodorescu European Polymer Journal 37 (2001) 1417-1422

polycondensation With ring-opening functional groups can be introduced into the main chain

of the polymer This polymer cannot be prepared by vinyl polymerization4

Milkovich first developed synthesis of graft polymer with uniform grafts via macromonomer

technique5 Schulz and Milkovich6 reported the synthesis of polystyrene macromonmers

through termination of living PS anions with methacryloyl chloride and their

copolymerization with butyl acrylate and ethyl acrylate

Candau Rempp et al7 obtained PS-g-PEO by reaction between living monofunctional PEO

and partly chloromethacrylated PS backbone (scheme 1) Characterization of the products by

light scattering GPC UV and NMR spectroscopy showed a high degree of grafting

Scheme 1

Ito et al8 used a macromonomer technique to obtain graft copolymers with uniform side

chains They synthesized a graft copolymer of PS with uniform PEO side chains through

copolymerization of styrene and PEO macromonomer (scheme 2) They obtained PEO

macromonomers using potassium tertiary butoxide as initiator and methacryloyl chloride or p-

vinyl benzyl chloride as terminating agent An apparent decrease in reactivities of both poly

(ethylene oxide) of macromonomers and comonomers was ascribed to the thermodynamic

repulsion between the macromonomer and the backbone9

4 Nagatsuta-cho Midori-ku Die Angewandte Makromolekulare Chemie 240 (1996) 171-180 5 R Milkovich USP 3 786 (1974) 116 6 G O Schulz R Milkovich J Appl PolymSci 27 (1982) 4773 7 Candau F Afchar F Taromi F Rempp P Polymer 18 (1977) 1253 8 Ito K Tsuchinda H Kitano T Yanada E Matsumoto T Polym J 17 (1985) 827 9 Ito K Tanak K Tanak H Imai G Kawaguchi S Itsumo S Macromolecules 24 (1991) 2348

Scheme 2

This type graft copolymers of styrene and ethylene oxide was also obtained by Xie et al10

through copolymerization of styrene with PEO macromonomer prepared by anionic

polymerization of EO in dimethylsulfoxide using potassium naphthalene in tetrahydofuran as

initiator followed by termination with methacryloyl chloride

The method of macromonomer synthesis developed by Xie et al11 has the advantage of

shorter reaction time and a larger range of molecular weight of the PEO macromonomer than

the usual method using potassium alcoholate as initiator PEO macromonomers with

molecular weight from 2 103 to 3 104 and MwMn = 107 ndash 112 can be obtained by this

method12

Only Xie and coworkers have published reports concerning the synthesis of copolymers with

uniform PS grafts obtained through copolymerization of epoxy ether terminated polystyrene

macromonomer with EO13 using a quaternary catalyst composed of triisobutyl-aluminium-

phosphoric acid-water-tertiary amine14 and epichlorohydrin (ECH)15

Free radical polymerization technique has also provided well-defined macromonomers of

poly (acrylic acid)16 vinyl benzyl-terminated polystyrene17 18 poly (t-butyl methacrylate)19

and poly (vinyl acetate)20

Recently Matyjaszewski et al21 employed atom-transfer radical polymerization (ATRP) to

prepare well-defined vinyl acetate terminated PS macromonomers Taking advantage of the

10 Xie H Q Liu J Xie D Eur Polym J 25 11 (1989) 1119 11 Xie HQ Liu J Li H J Macromol Sci Chem A 27 6 (1990) 725 12 Hong-Quan Xie and Dong Xie Prog Polym Sci 24 (1999) 275-313 13 HQ Xie WB Sun Polym Sci Technol Ser Vol 31 Advances in polymer synthesis Plenum Publ Corp (1985) 461 Polym Prepr 25 2 (1984) 67 14 HQ Xie JS Guo GQ Yu J Zu J Appl Polym Sci 80 2446 (2001) 15 HQ Xie SB Pan JS Guo European Polymer Journal 39 (2003) 715-724 16 K Ishizu M Yamashita A Ichimura Polymer 38 No21 (1997) 5471-5474 17 K Ishizu X X Shen Polymer 40 (1999) 3251-3254 18 K Ishizu T Ono T Fukutomi and K Shiraki J Polym Sci Polym Lett Edn 25 (1987) 131 19 K Ishizu and K Mitsutani J Polym Sci Polym Lett Edn 26 (1988) 511 20 T Fukutomi K Ishizu and K Shiraki J Polym Sci Polym Lett Edn 25 (1987) 175 21 Matyjaszewski K Beers K L Kern A Gaynor SG J Polym Sci Part A Polym Chem 36 (1998) 823

extremely low reactivity of polystyryl radical towards the vinyl acetate double bond they

used vinyl chloroacetate to initiate the polymerization of styrene to produce the desired

macromonomers This concept has been used similarly in the preparation of a vinyl acetate-

terminated PS macromonomers3 by conventional free-radical polymerization by employing

vinyl iodoacetate as a chain transfer agent possessing a double bond which does not

copolymerize with the monomer that forms the backbone of the macromonomer

12 Ring-Opening Polymerization Overview

Ring-opening polymerization (ROP) is a unique polymerization process in which a cyclic

monomer is opened to generate a linear polymer It is fundamentally different from a

condensation polymerization in that there is no small molecule by-product during the

polymerization Polymers with a wide variety of functional groups can be produced by ring-

opening polymerizations Ring-opening polymerization can proceed through a number of

different mechanisms depending on the type of monomer and catalyst involved Of the wide

range of polymers produced via ROP some have gained industrial significance for example

poly (caprolactam) and poly (ethylene oxide)22 ROP of cyclic esters such as ε-caprolactone

(CL) and L L-dilactide is gaining industrial interest due to their degradability23 The

mechanisms of interest in this work are coordination insertion and cationic

121 Polymerizability of Cyclic Compounds

The thermodynamic polymerizability of a cyclic monomer has been elegantly summarized by

Ivin24 Negative free energy change from monomer to polymer is the thermodynamic driving

force for the ring-opening

ΔG = ΔH ndash T ΔS

For small sized cyclic compounds the enthalpy term is negative and dominant The strains in

bond angles and bond lengths are released upon ring opening Such monomers can be almost

completely converted to polymers For medium sized cyclic monomers (5-7 membered rings)

the ring strain is small and the entropy is a small positive term Thus the overall driving force

(ΔG) is small and the extent of polymerization is little or no reaction For 8- 9- and 10-

22 KJ Ivin and T Saegusa Ring-opening polymerization Vol1 Ed Elsevier NY (1984) 23 MH Hartmann Biopolymers from Renewable Resources Ed DL Kaplan Springer Berlin (1998) 24 Ivin K J Makromol Chem Macromol Symp 4243 1 (1991)

membered monomers the enthalpy term is dominant and negative while the TΔS term is

relatively small The strain is due to the non-bonded interactions between atoms Essentially

complete conversion to polymer is possible When the ring size is very large and there is

virtually no ring-strain (ΔH ne 0) the driving force for ring-opening polymerization is the

large increase of entropy The polymerization should be an athermal process

Why not make polyethylene

In principle one could synthesize polyethylene from cyclohexane

There are two good reasons why this reaction cannot be performed

bull (Kinetic) Cyclohexane lacks any reactive functionality to get hold of

bull (Thermodynamic) Simple six membered rings are extremely stable

Free Energy (ΔG) of Polymerization for Cycloalkanes

The thermodynamic considerations for ring opening are illustrated by this graph (scheme 3) of

free energy (hypothetical) of polymerization from cycloalkanes with various ring sizes to

polyethylene (The two membered ring actually shows the data for ethylene CH2 = CH2)

Scheme 3

Three and four membered rings are quite strained so ring opening to polyethylene is

favorable if a suitable reaction pathway existed (Unfortunately no such reaction is known)

Six membered rings are stable so they can rarely be polymerized by ring opening Five and

seven membered rings are borderline cases so sometimes these can be polymerized Larger

rings have transanular steric interactions that cause some strain so rings of 8 members or

more can usually be polymerized Of course this graph changes when substitutions are made

to the rings (for example the presence of heteroatoms like O S and N or the introduction of

double bonds) However the graph for the simplest possible rings illustrates the trends in

other systems reasonably well

Even if the ring opening reaction is thermodynamically favorable there must be reaction

chemistry to get there In most cases the initiators used for ring opening polymerization are

polar or ionic species so the monomers must have groups that can react The most common

monomers for ring opening polymerization contain some kind of heteroatom in the ring as in

the examples of cyclic ethers esters amines amides etc At one extreme there are examples

such as the cyclic phosphazene shown that contain no carbon or hydrogen at all At the other

extreme just a carbon-carbon double bond will suffice for ring opening metathesis

polymerization as illustrated by norbornene

122 Mechanisms of Ring-opening Polymerization

In addition to the thermodynamic criterion there must be a kinetic pathway for the ring to

open and undergo the polymerization reaction Therefore the kinetics of the ring-opening of

the monomer should also be considered Ring-opening polymerization (ROP) can proceed

through a number of different mechanisms depending on the type of monomer and catalyst

involved Of the wide range of polymers produced via ROP some have gained industrial

significance for example poly (caprolactam) and poly (ethylene oxide)24 25 A variety of

mechanisms operate for ring-opening polymerizations including anionic cationic metathesis

and free radical mechanisms Examples of various ring-opening polymerizations are shown in

scheme 4

25 KJ Ivin and T Saegusa Ring-opening polymerization Vol1 Ed Elsevier NY (1984)

Scheme 4

123 Cationic Ring-Opening Polymerization of Heterocycles

A broad range of heterocyclic compounds can undergo cationic ring-opening polymerization

(CROP)26 CROP propagates either through an activated monomer or an activated chain end

mechanism In both cases the propagation involves the formation of a positively charged

species27 A major drawback of CROP is the occurrence of unwanted side reactions thus

limiting the molecular weight of the final product2829 The cationic ring-opening

polymerization of heterocycles has become of significant importance in polymer synthesis

due in part to the diverse variety of functionalized materials that can be prepared by this

method including natural andor biodegradable polymers30 31

Systematic studies of this type of polymerization started around the nineteen sixties Since

then several groups are involved in the kinetics reaction mechanisms and thermodynamics of

the ring-opening polymerization mostly of tetrahydofuran and dioxolane During the last

26 MH Hartmann Biopolymers from Renewable Resources Ed DL Kaplan Springer Berlin (1998) 27 T Endo Y Shibasaki F Sanda Journal of Polymer Science 40 (2002) 2190 28 CJ Hawker Dendrimers and Other Dendritic Polymers Ed JMJ Freacutechet DA Tomalia Wiley NY

(2001) 29 S Penczek Makroloekulare Chemie 134 (1970) 299 30 (a) Matyjaszewski K Ed Marcel Dekker Cationic Polymerization New York (1996) (b) Brunelle D J Ring-Opening Polymerization Ed Hanser Munich (1993) (c) Yagci Y and Mishra M K In Macromolecular Design Concept and Practice (d) Mishra M K Ed Polymer Frontiers New York (1994) 391 31 J Furukawa KTada in Kinetics and Mechanisms of Polymerization (EditKCFrisch SLReegen) 2 M

Dekker NY (1969) 159

years many papers on the synthesis and polymerization of several other cyclic ethers

monocyclic and bicyclic acetals have been published32 33

Examples of commercially important polymers which are synthesized via ring-opening

polymerization are summarized in scheme 5 include such common polymers as

polyoxyethylene (POE 4) poly (butylene oxide) (PBO 5) nylon 6 (6) and poly

(ethyleneimine) (7)

Scheme 5

The synthesis of ring-opened heterocycles is often mediated by compounds whose role is to

initiate the polymerization process This provides less opportunity to ldquotunerdquo polyheterocycle

properties through catalyst choice and has stimulated research to develop initiators which

function beyond the simple activation of polymerization such as living polymerization

initiators343536 chiral initiators3738 enzyme initiators39 and ring-opening insertion

systems4041 The cationic ring-opening polymerization involves the formation of a positively

32 HSumitomo MOkada Advanced PolymSci 28 (1978) 47 33 Chem Systemrsquos Process Evaluation Research Planning Program PERP report Polyacetal October (2002) 34 Matyjaszewski K Ed Marcel Dekker New York (1996) 35 Brunelle D J Ed Hanser Munich (1993) 36 Yagci Y Mishra M K Macromolecular Design Concept and Practice Mishra M K Ed Polymer Frontiers New York (1994) 391 37 NakanoT Okamoto Y and Hatada K JAm Chem Soc114 (1992) 1318 38 Novak B M Goodwin A A Patten T E and Deming T J Polym Prepr37 (1996) 446 39 Bisht K S Deng F Gross R A Kaplan D L and Swift G J Am Chem Soc 120 (1998)1363 40 AidaT and Inoue S J Am Chem Soc 107 (1985) 1358 41 Yasuda H Tamamoto H Yamashita MYokota K Nakamura A Miyake S Kai Y and Kanehisa N Macromolecules 26 (1993) 7134

charged species which is subsequently attacked by a monomer The attack results in a ring-

opening of the positively charged species Ethylene oxide can be polymerized by cationic

initiators as well (scheme 6)

Scheme 6

13 Cationic Polymerization of Cyclic Acetals

Acetal polymers also known as polyoxymethylene (POM) or polyacetal are formaldehyde-

based thermoplastics that have been commercially available for over 40 years

Polyformaldehyde is a thermally unstable material that decomposes on heating to yield

formaldehyde gas Two methods of stabilizing polyformaldehyde for use as an engineering

polymer were developed and introduced by DuPont in 1959 and Celanese in 1962

DuPonts route for polyacetal yields a homopolymer through the condensation reaction of

polyformaldehyde and acetic acid (or acetic anhydride)

The Celanese route for the production of polyacetal yields a more stable copolymer product

via the reaction of trioxane a cyclic trimer of formaldehyde and a cyclic ether (eg ethylene

oxide or 13 dioxolane)

The improved thermal and chemical stability of the copolymer versus the homopolymer is a

result of randomly distributed oxyethylene groups These groups offer stability to oxidative

thermal acidic and alkaline attack The raw copolymer is hydrolyzed to an oxyethylene end

cap to provide thermally stable polyacetal copolymer Polyacetals are subject to oxidative and

acidic degradation which leads to molecular weight deterioration Once the chain of the

homopolymer is ruptured by such an attack the exposed polyformaldehyde ends decompose

to formaldehyde and acetic acid Deterioration in the copolymer ceases however when one

of the randomly distributed oxyethylene linkages is reached42

Cationic polymerization of cyclic acetals exhibits some special features which makes this

system distinctly different from cationic polymerization of simple heterocyclic monomers for

instance cyclic ethers Linear acetals (including polyacetals) are more basic (nucleophilic)

than cyclic ones thus when polymer starts to form it does not constitute a neutral component

of the system but participates effectively in transacetalization reactions which lead to

redistribution of molecular weights and formation of a cyclic fraction These processes which

are usually described by the term ldquoscramblingrdquo have been studied by several authors43 44

Cationic polymerizations of heterocyclic monomers are initiated as in cationic

polymerization of vinylic monomers by electrophilic agents such as the protonic acids (HCl

H2SO4 HClO4 etc) Lewis acids which are electron acceptors by definition and compounds

capable of generating carbonium ions can also initiate polymerization Examples of Lewis

acids are AlCl3 SnCl4 BF3 TiCl4 AgClO4 and I2 Lewis acid initiators required a co-

initiator such as H2O or an organic halogen compound Initiation by Lewis acids either

requires or proceeds faster in the presence of either a proton donor (protogen) such as water

alcohol and organic acids or a cation donor (cationogen) such as t-butyl chloride or

triphenylmethyl fluoride

The polymerization of a heterocyclic monomer initiated by a protonic acid usually starts with

opening of the monomer ring via oxonium sites that are formed upon alkylation (or

protonation) of the monomer

42 Chem Systemrsquos Process Evaluation Research Planning Program PERP report Polyacetal October (2002) 43 S Penczek P Kubisa and K Matyjaszewski Adv Polym Sci 37 (1980) 44 E Franta P Kubisa J Refai S Ould Kada and L Reibel Makromol Chem Makromol Symp 1314

(1988) 127-144

Protonation

BF3 H2O H BF3 OH+ +O

Acylation

R CO SbF6 +

OR CO O SbF6

Alkylation

Et3O BF4 +

OC2H5 Et2O BF4O +

Hydrogen transfer

C SbF6 +O

C SbF6H O+

O + O O+ H O SbF6

In general initiation step can be shown as

R O++R A O

The mechanism of chain growth involves nucleophilic attack of the oxygen of an incoming

monomer onto a carbon atom in α-position with respect to the oxonium site whereby the

cycle opens and the site is reformed on the attacking unit

O(CH2)4

A+O(CH2)4

Growing chain terminates with nucleophilic species as shown below

O (CH2)4 O+[ ]n

A O (CH2)4[ ]n

AO ( CH2 )4

Triflic initiators like trifluoromethane sulfonic acid derivatives can also be employed as an

initiator in the cationic polymerization of heterocyclics in this case initiation step follows

alkylation mechanism

CF3 SO3CH3 +O

CH3 CF3SO3O

CF3SO3

+ O CH3O(CH2)4 O CF3SO3

Ion pairs are in equilibrium with the ester form

(CH2)4 O CF3SO3 (CH2)4 O(CH2)4 O SO2CF3

If instead of ester triflic anhydride is used as initiator the same reaction can occur at both

chain ends and anhydride behaves as a bifunctional initiator

CF3SO2OSO2CF3 nO

+ CF3SO2 O (CH2)4 O (CH2)4 O SO2CF3n-1

(CH2)4 O (CH2)4 n-3

O O CF3SO3 CF3SO3

In the case of living cationic polymerization the growing sites are long living provided the

reaction medium does not contain any transfer agents such as alcohols ethers amines or

acids The reaction mechanism then involves only initiation and propagation steps and the

polymers formed are living The active sites are deactivated by addition of an adequate

nucleophile such as excess water tertiary amines alkoxides phenolates or lithium bromide

O(CH2)4

(CH2)4 O(CH2)4 OH H

++ H2O

+(CH2)4 O(CH2)4 NR3 SbF6

ONa+(CH2)4 O(CH2)4 O + NaSbF6

+ LiBr

(CH2)4 O(CH2)4 Br LiSbF6+

However facts concerning the real mechanism are scarce In order to progress further in

understanding the cationic polymerization of heterocycles initiated with a Bronsted acid

kinetic studies of simple ring-opening reactions of heterocyclic monomer rings by acids in

nonpolar aprotic and nonbasic solvents (inert solvents) have been performed45

14 Synthesis of Functionalized Poly (1 3-Dioxolane)

1 3-Dioxolane (DXL) belongs to the class of heterocyclic monomers containing acetal

functions that only polymerize cationically46 A specific characteristic of DXL is its lower

nucleophilicity as compared to that of the acetal functions in PDXL Thus in competition

with the propagation reaction the active sites at the growing polymer ends ie cyclic

dioxolenium cations will also be involved in a reaction with the acetal functions in the

polymer chains25 43 This continuous transacetalization process results in a broadening of the

molecular weight distribution and in the formation of cyclic structures47 It has been shown

that these intermolecular transfer reactions can be applied to introduce reactive end groups on

both chain ends of PDXL by the addition of a low molar mass formal as chain transfer agent

during the polymerization The molecular weight of the linear polymers is governed by the

ratio of reacted monomer to transfer agent and is generally well controlled up to 10 000gmol

141 Reaction of 1 3-Dioxolane and Hydroxyl- Containing Compounds

Classical initiation induces polymerization through cyclic tertiary oxonium ions which are

responsible for the formation of an important quantity of cyclic oligomers48

45 L Wilczek and J Chojnowski Macromolecules 14 (1981) 9-17 46 PH Plesch and PH Westermann Polymer10 (1969)105 47 K Matyaszewski M Zielinski P Kubisa S Slomokowski J Chojnowski and S Penczek Makromol

Chem 181 (1980) 1469 48 S Penczek and P Kubisa Comprehensive Polymer Sci Ed by G Allen and JC Bevington Pergamon Press 3(1989) 787

In several preceding articles Franta et al have investigated the cationic polymerization of

cyclic acetals in the presence of a diol49 50 in particular polymerization of 13-dioxolane

(DXL) and 13-dioxepane (DXP) in the presence of an oligoether diol (αω-dihydroxy-poly

(tetrahydofuran)) or (αω-dihydroxy-poly(ethylene oxide)) In all cases a similar behavior was

observed Cyclic oligomers are present in quantities as in the case of polymerization of DXL

in the absence of hydroxyl containing compounds51

When substituted oxiranes such as propylene oxide or epichlorohydrin are polymerized

according to the ldquoActivated Monomerrdquo mechanism (AM) Cyclic oligomers can be

eliminated52 53 In the AM mechanism polymerization of ethylene oxide however the

reaction of a protonated monomer molecule with a polymer chain leads to side reactions

including cyclization by the Active Chain End (ACE) mechanism53 Thus it is not

unexpected that in the polymerization of cyclic acetals due to the higher nucleophilicity of

the linear acetals located on the chain reactions with the latter will take place

The addition of a protonated DXL onto a hydroxyl group-containing compound is

accompanied by transacetalization involving a monomer molecule

In order to shed some light on the reactions involved Franta et al54 used a monoalcohol

methanol instead of a diol The results confirmed the occurrence of the Active Monomer

mechanism but dimethoxymethane was observed evidence of transacetalization between

methanol and dioxolane

Thus in the DXL-ethylene glycol (EG) system the presence of unreacted EG is in fact due to

the following equilibria

This equation shows the stoichiometry of the reaction rather than its actual mechanism the

reaction certainly has to involve an addition product as a first step

49 L Reibel H Zouine and E Franta Makromol Chem Makromol Symp 3 (1986) 221 50 E Franta P Kubisa J Refai S Ould Kada and L Reibel ACS Polymer Prepr 29 1 (1988) 83 51 J A Semlyen and J M Andrews Polymer 13 (1972) 142 52 M Wojtania P Kubisa and S Penczek Makromol Chem Makromol Symp 6 (1986) 201 53 P Kubisa Makromol Chem Makromol Symp 1314 (1988) 203 54 E Franta Kubisa S Ould Kada and L Reibel Makromol Chem Makromol Symp 60 (1992) 145-154

In the next step transacetalization occurs

The products of transacetalization are formed fast as compared to the addition product54 This

indicates that the last reaction is not slower and probably faster than the previous one

Consequently it has been found that although polymerization of DXL in the presence of

hydroxyl group containing compounds proceeds initially by a stepwise addition of protonated

monomer to the hydroxyl terminated linear species in agreement with the AM mechanism but

already at this stage fast transacetalization proceeds leading to formation of O-CH2-O links

between two oligodiols and liberation of ethylene glycol

The synthesis of α ω-dihydroxy-PDXL chains is based on the activated monomer

mechanism When DXL is polymerized by strong protonic acids such as triflic acid in the

presence of a diol the PDXL chains are essentially linear and carry end-standing OH

functions Despite the occurrence of some side reactions this mechanism leads to α ω-

dihydroxy-PDXL the molecular weight of which is controlled by the molar ratio of DXL

consumed to diol introduced It has been shown that the polydispersity is on the order of 14

and that molar masses up to 10 000 gmol can be covered

142 Synthesis of Poly (1 3-Dioxolane) Macromonomers

Macromonomers are useful intermediates to prepare graft copolymers and have indeed been

used extensively In order to prepare PDXL macromonomers Franta and al54 have used p-

isopropenylbenzylic alcohol (IPA) as an initiator and triflic acid as a catalyst

The following polymeric species were identified

Scheme 7

A is the most abundant compound it corresponds to 50 to 60 weight-wise It is a

macromonomer

B corresponds to 20 to 25 weight-wise It carries two p-isopropenyl functions

C corresponds to 20 to 25 weight-wise It carries no p-isopropenyl function but two

hydroxyl groups

As a result preparation of PDXL macromonomers leads to the preparation of PDXL chains

carrying polymerizable double bonds at their ends Nevertheless because of transacetalization

reaction described above a mixture of products was obtained54

Kruumlger et al55 used similar method to prepare macromonomers and come out to the same

conclusions in terms of structure and claim that a clear distinction should be made between

the products obtained and the mechanism responsible for their formation

15 Amphiphilic Graft Copolymers

151 Graft Copolymers

The increasing complexity of polymer applications has required the production of materials

with varied properties Often homopolymers do not afford the scope of attributes necessary to

many applications Copolymerization allows the formulation of polymer materials with

properties characteristic of two homopolymers contained in a single copolymer material The

monomers within a copolymer can be distributed in various fashions random statistical

alternating segmented block or graft56

55 H Kruumlger H Much G Schulz and C Wehrstedt Makromol Chem 191 (1990) 907 56 Tidwell P W and Mortimer G A J Polymer Sci Pt A 3 (1965) 369-387

Scheme 8

Graft copolymers are similar to block copolymers in that they possess long sequences of

monomer units However graft copolymer architecture differs substantially from typical

block copolymers In graft copolymers monomer sequences are grafted or attached to points

along a main polymer chain Grafted chains generally possess molecular weights less than

that of the main chain

These side chains have constitutional or configurational features that differ from those in the

main chain57

The simplest case of a graft copolymer can be represented by A-graft-B or the arrangement

and the corresponding name is polyA-graft-polyB where the monomer named first (A in this

case) is that which supplied the backbone (main chain) units while that named second (B) is

in the side chain(s)

Typical syntheses of the grafts occur by polymerization initiated at some reactive point along

the backbone or by copolymerization of a macromonomer Polymerization from the polymer

backbone is possible via anionic cationic and radical techniques but all require some

functional unit capable of further reaction58

Well defined graft copolymers are most frequently prepared by either

a)ldquografting throughrdquo or b)ldquografting fromrdquo controlled polymerization process

57 IUPAC Pure Appl Chem 40 (1974) 477-491 58 G Odian Principles of Polymerization 3rd ed New York John Wiley and Sons Inc (1991)

a) Grafting though the ldquografting throughrdquo method (or macromonomer method) is one of the

simplest ways to synthesize graft copolymers with well defined side chains

Scheme 9

Typically a low molecular weight monomer is radically copolymerized with a methacrylate

functionalized macromonomer This method permits incorporation of macromonomers

prepared by other controlled polymerization processes into a backbone prepared by a CRP

Macromonomers such as polyethylene59 60 poly (ethylene oxide)61 polysiloxanes62 poly

(lactic acid)63 and polycaprolactone64 have been incorporated into a polystyrene or poly

(methacrylate) backbone Moreover it is possible to design well-defined graft copolymers by

combining the ldquografting throughrdquo macromonomers prepared by any controlled polymerization

process and CRP65 This combination allows control of polydispersity functionality

copolymer composition backbone length branch length and branch spacing by consideration

of MM ratio in the feed and reactivity ratio Branches can be distributed homogeneously or

heterogeneously and this has a significant effect on the physical properties of the

materials6263

b) Grafting from the primary requirement for a successful grafting from reaction is a

preformed macromolecule with distributed initiating functionality

59 Hong S C Jia S Teodorescu M Kowalewski T Matyjaszewski K Gottfried A C and Brookhart M J Polym Sci Polym Chem Ed 40 (2002) 2736-2749 60 Kaneyoshi H Inoue Y and Matyjaszewski K Macromolecules 38 (2005) 5425-5435 61 Neugebauer D Zhang Y Pakula T Sheiko S S and Matyjaszewski K Macromolecules 36 (2003) 6746-6755 62 Shinoda H Matyjaszewski K Okrasa L Mierzwa M and Pakula T Macromolecules 36 (2003) 4772-4778 63 Shinoda H and Matyjaszewski K Macromolecules 34 (2001) 6243-6248 64 Hawker C J et al Macromol Chem Phys 198 (1997) 155-166 65 Beers K L Kern A Gaynor S G and Matyjaszewski K J Polym Sci Part A Polym Chem 36 (1998) 823-830

Scheme 10

Grafting-from reactions have been conducted from polyethylene66 67 polyvinylchloride68 69

and polyisobutylene70 71 The only requirement for an ATRP is distributed radically

transferable atoms along the polymer backbone The initiating sites can be incorporated by

copolymerization68 be inherent parts of the first polymer69 or incorporated in a post-

polymerization reaction70

Graft copolymers perform similar functions to block copolymers in that they contain moieties

with varying properties Compatibilization represents a major area of application for grafts

because the grafted chains can be used to solubilize a polymer blend system containing two

immiscible polymers Additionally graft copolymers offer unique solution mechanical and

morphological properties that make them ideal for utilization as viscosity modifiers and

thermoplastic elastomers72 The unique molecular architecture of graft copolymers leads to

peculiar morphological properties The chain lengths of the grafted arms and backbone block

dictate the morphology that arises in the polymer Changes in the composition of the graft

copolymer alter the resulting polymer morphology A variety of morphologies is possible

ranging from lamellar to cylindrical to spherical73

Graft copolymers offer all properties of block copolymers but are usually easier to synthesize

Moreover the branched structure offers important possibilities of rheology control

Depending on the nature of their backbone and side chains graft copolymers can be used for a

wide variety of applications such as impact-resistant plastics thermoplastic elastomers

66 Inoue Y Matsugi T Kashiwa N and Matyjaszewski K Macromolecules 37 (2004) 3651-3658 67 Kaneyoshi H et al Polymeric Materials Science and Engineering 91 (2004) 41-42 68 Paik H J Gaynor S G and Matyjaszewski K Macromol Rapid Commun 19 (1998) 47-52 69 Percec V and Asgarzadeh F J Polym Sci Part A Polym Chem 39 (2001) 1120-1135 70 Hong S C et al Polymeric Materials Science and Engineering 84 (2001) 767-768 71 Matyjaszewski K et al In PCT Int Appl (CMU USA) WO 9840415 (1998) 230 72 Gido S P Lee C Pochan D J Pispas S Mays J W and Hadjichristidis N Macromolecules 29 (1996) 7022-7028 73 Ruokolainen J Saariaho M Ikkala O ten Brinke G Thomas E L Torkkeli M and Serimaa R Macromolecules 32 (1999) 1152-1158

compatibilizers viscosity index improvers and polymeric emulsifiers74 75 The state-of-the-

art technique to synthesize graft copolymers is the copolymerization of macromonomers

(MM) with low molecular weight monomers76 In most cases conventional radical

copolymerization has been used for this purpose Using living polymerizations for both the

synthesis of the macromonomers and for the copolymerization offers the highest possible

control of the polymer structure In all these copolymerizations beside the desired graft

copolymers with at least two side chains a number of unwanted products can be expected

unreacted macromonomer ungrafted backbone and backbone with only one graft (star

copolymer) The latter is undesirable for applications as thermoplastic elastomer

Conventional and controlled copolymerizations lead to different copolymer structures In

conventional radical copolymerization the polymers show a broad molecular weight

distribution (MWD) and chemical heterogeneity of first order

152 Amphiphilic Copolymers

A characteristic feature of an amphiphilic polymer is that it contains both hydrophilic and

hydrophobic groups This type of polymer associates in aqueous solution and exhibits several

interesting features and can be used in connection with many industrial and pharmaceutical

applications Usually there is only a few mol of the hydrophobic moieties in order to make

the polymer water-soluble Due to the hydrophobicity of the amphiphilic polymers they have

a tendency to form association structures in aqueous solution by mutual interaction andor

interaction with other cosolutes such as surfactants and colloid particles

In particular the grafting of hydrophilic species onto hydrophobic polymers is of great utility

Amphiphilic graft copolymers so prepared often display enhanced surface properties such as

improved resistance to the adsorption of oils and proteins biocompatibility and reduced static

charge buildup

The synthesis of graft copolymers based on commercial polymers is most commonly

accomplished free radically Free radicals are produced on the parent polymer chains by

exposure to ionizing radiation andor a free-radical initiator77 78 Alternatively peroxide

groups are introduced on the parent polymer by ozone treatment79 80 The resulting reactive

74 Dreyfuss P Quirk R P Encyclopedia of Polymer Science amp TechnologyVol 7 Wiley New York (1987)

551 75 Roos S Muumlller A H E Kaufmann M Siol W and Auschra C Quirk R P Ed ACS Symp Ser (1998) 696-208 76 Schulz G O and Milkovich R Journal of Appl Polym Sci 27 (1982) 4773 77 Xu G X and Lin S G Journal of Macromol SciRev Macromol Chem Phys C34 (1994) 555-606 78 Mukherjee A K and Gupta B D J Journal of Macromol Sci Chem A19 (1983) 1069-1099 79 Boutevin B Robin J J and Serdani A Eur Polym Journal 28 (1992) 1507

sites serve as initiation sites for the free radical polymerization of the comonomer A

significant disadvantage of these free radical techniques is that homopolymerization of the

comonomer always occurs to some extent resulting in a product which is a mixture of graft

copolymer and homopolymer Moreover backbone degradation and gel formation can occur

as a result of uncontrolled free radical production often limiting the attainable grafting

density81 For example amphiphilic graft copolymers synthesized from PEO macromonomer

and hydrophobic comonomers82 83were found to form micellar aggregates in polar medium

such as water wateralcohol alcohol dimethylformamide These phase separation processes

take place also during polymerization and supposedly affect not only the polymerization

kinetics but also properties of resulting copolymers So far unanswered remains the question

of molecular characteristics of reaction products including homopolymers from

macromonomer or comonomer formed under both the homogeneous and heterogeneous

(micellar) reaction conditions Modern liquid chromatographic techniques allow

discrimination of polymeric constituents differing in their chemical structure andor physical

architecture Subsequently the molar mass and molar mass distribution of constituents can be

assessed Recently analyzed products of dispersion copolymerization of polyethylene oxide

methacrylate macromonomer with styrene contained rather large amount of polystyrene

homopolymer84

In the main application areas for amphiphilic polymers the solution properties are of

fundamental importance In many industrial applications association and adsorption

phenomena of the polymers in solution are design properties Consequently a deep

understanding of these phenomena is necessary for the development of new specific

chemicals and new processes The research goals are to clarify the relations between the

molecular structure of amphiphilic polymers and their properties in aqueous solution A

further goal is to develop theoretical models for the description of the behavior of amphiphilic

polymers in solution and at surfaces Several projects concern the self-assembly of

amphiphilic polymer molecules and the association behavior of surfactants and

hydrophobically modified hydrophilic polymers such as cellulose derivatives Studies of

amphiphilic model polymers such as ethylene oxide block and graft copolymers are carried

80 Liu Y Lee J Y Kang E T Wang P and Tan K L React Funct Polym 47 (2001) 201-213 81 Wang X-S Luo N Ying S-K Polymer 40 (1999) 4515-4520 82 Furuhashi H Kawaguchi S Itsuno S and Ito K Colloid Polym Sci 227 (1997) 275 83 Capek I Adv Polym Sci 1 (1999) 145 84 Nguyen SH Berek D Capek I J Polym Sci submitted for publication

out in order to gain fundamental knowledge on the solution behavior of amphiphilic

polymers

16 Kinetics of Free Radical Polymerization

Free radical polymerization is the most widespread method of polymerization of vinylic

monomers Free radical polymerizations are chain reactions in which every polymer chain

grows by addition of a monomer to the terminal free radical reactive site called ldquoactive

centerrdquo The addition of the monomer to this site induces the transfer of the active center to

the newly created chain end Free radical polymerization is characterized by many attractive

features such as applicability for a wide range of polymerizable groups including styrenic

vinylic acrylic and methacrylic derivatives as well as tolerance to many solvents small

amounts of impurities and many functional groups present in the monomers

161 Kinetics of free radical addition Homo and Copolymerization

Understanding of chemical kinetics during homo- and copolymerization is crucial for

copolymer synthesis The discussion below will review the kinetics of free radical initiated

polymerizations and copolymerizations

The three main kinetic steps that occur during polymerization are (1) initiation (2)

propagation and (3) termination

1 Initiation

The initiation step is considered to involve two reactions creating the free radical active

center The first event is the production of free radicals Many methods can be used to initiate

free radical polymerizations such as thermal initiation without added initiator or high energy

radiation of the monomers However free radicals are usually generated by the addition of

initiators that form radicals when heated or irradiated Two common examples of such

compounds which afford free radicals are benzoyl peroxide (BPO) and azobisisobutyronitrile

(AIBN)

Figure 1 Generation of Free Radicals by Thermal Decomposition of Benzoyl Peroxide

Figure 2 Decomposition of Azobisisobutyronitrile to Form Free Radicals

Figure 1 depicts the thermal decomposition of BPO to form two oxy-radicals and Figure 2

depicts the decomposition of AIBN to form two nitrile stabilized carbon based radicals

(equation 1)

In equation 1 kd is the rate constant which describes the first order initiation process The

radical that is formed can now add to the double bond of the monomer and initiate

polymerization

The symbol M will represent the monomer and the rate constant for this process will be ki as

described in equation 2

Together these two reactions the radical generation and the monomer addition to the radical

form the process of initiation Usually the assumption that is taken into account is that the

first step is the rate determining step This means that the decomposition to form the radical

is much slower than the monomer addition to the free radical Therefore the equation for the

rate of radical formation ri is

The number 2 is obtained from the fact that a maximum of two radicals can be generated for

the initiation

But not all of the primary radicals produced by the decomposition of the initiator will

necessarily react with the monomer which means several other competing reactions may

occur85 Therefore in order to determine the rate of initiation the fraction of initially formed

radicals that actually start chain growth will be denoted by f and the rate of initiation equation

becomes

2 Propagation

Now the propagation of the reaction will proceed through the successive addition of

monomer to the radicals This type of process can be expressed in the following form

85 Painter P C and Coleman M M Fundamentals of Polymer Science Technomic Publishing Inc Lancaster PA (1997)

And further generalizing the reaction scheme gives

The assumption that the reactivity of the addition of each monomer is independent of the

chain length is evident in these two equations and was postulated by Flory 58 86 The use of

the rate constant kp for both of these equations imply that the rate constant is independent of

chain length The rate of the propagation rp of this polymerization or the rate of monomer

removal is thus given by

3 Termination

The termination of these growing radical chains occurs in principally two different ways The

first way is the formation of a new bond in between the two radicals this is called

combination Secondly the radical chains can terminate by disproportionation This is a

process where a hydrogen atom from one of the chains is transferred to the other and the chain

that the proton was removed from forms a double bond These reactions are represented as

follows

Figure 3 Termination by Combination

86 Moad G Solomon D H The Chemistry of Free Radical Polymerization Pergamon Press New York (1995)

Figure 4 Termination by Disproportionation

Schematically the reactions can be represented as follows

Where the rate constant of termination by combination is denoted by ktc and the rate constant

of termination by disproportionation is denoted by ktd Since both of these reactions use two

radical species and have the same kinetics the overall equation for the rate of termination is

written as

where kt = ktc + ktd and the number 2 imply there are two radicals that are terminated in

each termination reaction The monomer structure and the temperature are what determines

the type of termination that is most dominant in the reaction For most systems the amount of

one termination type far exceeds the other termination type

The further calculations for the rate of polymerization Rp and the degree of conversion as a

function of time can now be developed The assumption of the steady state concentration of

transient species must be used here where the transient species is the radical M For the

steady state approximation to hold true the rate at which initiation occurs ri must be equal to

the rate at which termination occurs rt or in other words radicals must be generated at the

same rate at which they are terminated This assumption gives the equation

This equation then gives an expression for the radical species

Experimentally this value would be difficult to measure in the laboratory and therefore this

equation must be used in the subsequent equations that follow By further substitution an

expression for the rate of polymerization Rp can be obtained because it equals the rate of

propagation

From this equation it can be deduced that the rate of polymerization is directly proportional

to the monomer concentration and to the initiator concentration to the one half power In

other words Rp is first order with regards to the monomer concentration and half order to the

initiator concentration

When the conversion is low the assumption that the initiator concentration is constant is

reasonable but the consumption of the initiator can be added into the calculations Therefore

Then integration can be performed

Finally the rate of polymerization becomes

This equation can be broken into three different parts

The second term indicates that the rate of polymerization is still proportional to the monomer

concentration to the first power and the initiator concentration to the one half power but the

initiator concentration is now the initial concentration Therefore by increasing the initial

concentration of an initiator in a solution polymerization the rate of the reaction should

increase proportionally to the square root of the amount of initiator added The third term

indicates that as the initiator is consumed the polymerization slows down exponentially with

time as well as its slowing down due to monomer depletion

The first term in the brackets suggests that the rate of polymerization is proportional to kp

kt12 When experiments are performed to probe the kinetics of reactions in solution the

expected first order dependence on monomer concentration is observed But when the

experiment is performed in concentrated solvents or even in the bulk the polymerization

kinetics accelerate The reason for this anomaly is that the viscosity increases as the

polymerization proceeds because the polymer has a higher viscosity than the monomers The

kp is not affected but the kt is

The degree of conversion can now be expressed as a function of time by knowing that

By substituting the earlier equation for Rp and integrating that equation one can obtain this

Furthermore ([M]0 ndash [M]) [M]0 is equal to the degree of conversion and is the fraction of

the monomer that has been reacted where [M] is the concentration of the monomer that has

been left after the reaction and [M]0 is the initial monomer concentration Therefore ([M]0 ndash

[M]) is the concentration of the monomer that has reacted The conversion can then be

expressed as

This can also be expressed as

As is always the case the conversion never quite reaches 100 value or a factor of 1 given by

the exponential term So if the time goes to infinity the expression that is obtained for

maximum conversion that is less than 1 by an amount that is dependent on the initial initiator

concentration is

If the steady state approximation for the initiator concentration had been carried through these

calculations and equations then the conversion would approach a value of 1 after a long

period of time

Distributions on the average distribution of chain lengths during and after a polymerization

are present in free radical polymerizations This is due to the naturally but statistically

random termination reactions that occur in the solution with regard to chain length The

kinetic chain length v is the rate of monomer addition to growing chains over the rate at

which chains are started by radicals which is the expression for the number average chain

length In other words it is the average number of monomer units per growing chain radical

at a certain instant87 Therefore the initiator radical efficiency in polymerizing the monomers

87 Rosen S L Fundamental Principles of Polymeric Materials John Wiley and Sons New York (1993)

When termination occurs mainly by combination the chain length for the polymer chains on

the average doubles in size assuming nearly equal length chains combine But if

disproportionation mainly occurs the growing chains do not undergo any change in chain

length during the process So the expressions are thus

A new term can be used to more generally express the average chain length of the growing

polymer chain xn This new term is the average number of dead chains produced per

termination ξ This value is equal to the rate of dead chain formation over the rate of the

termination reactions The equations take into account that in combination only one dead

chain is produced and in disproportionation reactions two dead chains are produced

Therefore

Furthermore the instantaneous number average chain length can be expressed in terms of the

rate of addition of the monomer units divided by the rate of dead polymers forming This is

shown as

From this equation82 one can clearly see that the rate of polymerization is proportional to the

initiator concentration to the one half power [I]12 and that the instantaneous number average

chain length xn is proportional to the inverse of the initiator concentration to the one half

power 1[I]12 Thus if the polymerization was accelerated by using more initiator the chains

will end up to be shorter which may not be desirable85

17 Chain Growth Copolymerization

171 Copolymerization Equations

Chain polymerizations can obviously be performed with mixtures of monomers rather than

with only one monomer For many free radical polymerizations for example acrylonitrile and

methyl acrylate two monomers are used in the process and the subsequent copolymer might

be expected to contain both of the structures in the chain This type of reaction that employs

two comonomers is a copolymerization The reactivity and the relative concentrations of the

two monomers should determine the concentration of each comonomer that is incorporated

into the copolymer The application of chain copolymerizations has produced much important

fundamental information Most of the knowledge of the reactivities of monomers via

carbocations free radicals and carbanions in chain polymerizations has been derived from

chain copolymerization studies The chemical structure of these monomers strongly

influences reactivity during copolymerization Furthermore from the technological viewpoint

copolymerization has been critical to the design of the copolymer product with a variety of

specifically desired properties As compared to homopolymers the synthesis of copolymers

can produce an unlimited number of different sequential arrangements where the changes in

relative amounts and chemical structures of the monomers produce materials of varying

chemical and physical properties

Several different types of copolymers are known and the process of copolymerization can

often be changed in order to obtain these structures A statistical or random copolymer may

obey some type of statistical law which relates to the distribution of each type of comonomer

that has been incorporated into the copolymer Thus for example it may follow zero- or first-

or second-order Markov statistics88 Copolymers that are formed via a zero-order Markov

process or Bernoullian contain two monomer structures that are randomly distributed and

could be termed random copolymers

ndashAABBBABABBAABAmdash

Alternating block and graft copolymers are the other three types of copolymer structures

Equimolar compositions with a regularly alternating distribution of monomer units are

alternating copolymers

ndashABABABABABABA--

A linear copolymer that contains one or more long uninterrupted sequences of each of the

comonomer species is a block copolymer

--AAAAAAAA-BBBBBBBBB--

A graft copolymer contains a linear chain of one type of monomer structure and one or more

side chains that consist of linear chains of another monomer structure

--AAAAAAAAAAAAAmdash

For this discussion the main focus will be on randomly distributed or statistical copolymers

Copolymer composition is usually different than the composition of the starting materials

charged into the system Therefore monomers have different tendencies to be incorporated

into the copolymer which also means that each type of comonomer reacts at different rates

with the two free radical species present Even in the early work by Staudinger89 it was

noted that the copolymer that was formed had almost no similar characteristics to these of the

homopolymers derived from each of the monomers

Furthermore the relative reactivities of monomers in a copolymerization were also quite

different from their reactivities in the homopolymerization Thus some monomers were more 88 Mark H F Bikales N M Overberger C G and Menges G Eds Wiley-Interscience New York Vol 4

(1986) 192-233 89 Staudinger H Schneiders J Ann Chim 541 (1939) 151

reactive while some were less reactive during copolymerization than during their

homopolymerizations Even more interesting was that some monomers that would not

polymerize at all during homopolymerization would copolymerize relatively well with a

second monomer to form copolymers It was concluded that the homopolymerization features

do not easily directly relate to those of the copolymerization

Alfrey (1944) Mayo and Lewis (1944) and Walling (1957)909192 demonstrated that the

copolymerization composition can be determined by the chemical reactivity of the free radical

propagating chain terminal unit during copolymerization Application of the first-order

Markov statistics was used and the terminal model of copolymerization was proposed The

use of two monomers M1 and M2 during copolymerization leads to two types of propagating

species The first of these species is a propagating chain that ends with a monomer of

structure M1 and the second species is a propagating chain that ends with a monomer structure

M2 For radically initiated copolymerizations the two structures can be represented by

M1 and M2 where the zig-zag lines represent the chain and the M

represents the radical at the growing end of the chain The assumption that the reactivity of

these propagating species only depends on the monomer unit at the end of the chain is called

the terminal unit model58 If this is so only four propagation reactions are possible for a two

monomer system The propagating chain that ends in M1 can either add a monomer of type

M1 or of type M2 Also the propagating chain that ends in M2 can add a monomer unit of

type M2 or of type M1 Therefore these equations can be written with the rate constants of

reactions93

90 Alfrey T Bohrer J Jand Mark H Copolymerization Interscience New York (1952) 91 Mayo F R and Lewis F M J Am Chem Soc 66 (1944) 4594 92 Walling C Free Radicals in Solution Wiley New York Chap 4 (1957) 93 Flory P J Principles of Polymer Chemistry Cornell University Press Ithaca (1953)

The rate constant for the reaction of the propagating chain that ends in M1 and adds another

M1 to the end of the chain is k11 and the rate constant for the reaction of the propagating

chain that ends in M2 and adds M1 to the end of the chain is k21 and so on

The term self-propagation refers to the addition of a monomer unit to the chain that ends with

the same monomer unit and the term cross-propagation refers to a monomer unit that is added

the end of a propagating chain that ends in the different monomer unit These (normally)

irreversible reactions can propagate by free radical anionic or cationic processes although

active lifetimes could be very different

As indicated by reactions 30 and 32 monomer M1 is consumed and as indicated by reactions

31 and 33 monomer M2 is consumed The rates of entry into the copolymer and the rates of

disappearance of the two monomers are given by

In order to find the rate at which the two monomers enter into the copolymer equation 34

is divided by equation 35 to give the copolymer composition equation

The low concentrations (eg 10-8 molesliter) of the radical chains in the systems are very

hard to experimentally determine So to remove these from the equation the steady state

approximation is normally employed Therefore a steady state concentration is assumed for

both of the species M1 and M2 separately The interconversion between the two

species must be equal in order for the concentrations of each to remain constant and hence the

rates of reactions 31 and 32 must be equal

Rearrangement of equation 37 and combination with equation 36 gives

This equation can be further simplified by dividing the right side and the top and bottom by

k21 [M2] [M1] The results are then combined with the parameters r1 and r2 which are

defined to be the reactivity ratios

The most familiar form of the copolymerization composition equation is then obtained as

The ratio of the rates of addition of each monomer can also be considered to be the ratio of the

molar concentrations of the two monomers incorporated in the copolymer which is denoted

by (m1m2) The copolymer composition equation can then be written as

The copolymer composition equation defines the molar ratios of the two monomers that are

incorporated into the copolymer d[M1] d[M2] As seen in the equation this term is directly

related to the concentration of the monomers that were in the feed [M1] and [M2] and also

the monomer reactivity ratios r1 and r2 The ratio of the rate constant for the addition of its

own type of monomer to the rate constant for the addition of the other type of monomer is

defined as the monomer reactivity ratio for each monomer in the system When M1

prefers to add the monomer M1 instead of monomer M2 the r1 value is greater than one

When M1 prefers to add monomer M2 instead of monomer M1 the r1 value is less than

one When the r1 value is equal to zero the monomer M1 is not capable of adding to itself

which means that homopolymerization is not possible

The copolymer composition equation can also be expressed in mole fractions instead of

concentrations which helps to make the equation more useful for experimental studies In

order to put the equation into these terms F1 and F2 are the mole fractions of M1 and M2 in the

copolymer and f1 and f2 are the mole fractions of monomers M1 and M2 in the feed

Therefore

Then combining equations 42 43 and 40 gives

This form of the copolymer equation gives the mole fraction of monomer M1 introduced into

the copolymer58

Different types of monomers show different types of copolymerization behavior Depending

on the reactivity ratios of the monomers the copolymer can incorporate the comonomers in

different ways

The three main types of behavior that copolymerizations tend to follow correspond to the

conditions where r1 and r2 are both equal to one when r1 r2 lt 1 and when r1 r2 gt 1

bull A perfectly random copolymerization is achieved when the r1 and r2 values are both

equal to one This type of copolymerization will occur when the two different types of

propagating species M1 and M2 show the exact same preference for the addition of

each type of monomer In other words the growing radical chains do not prefer to add one of

the monomers more than the other monomer which results in perfectly random incorporation

into the copolymer

bull An alternating copolymerization is defined as r1 = r2 = 0 The polymer product in

this type of copolymerization shows a non-random equimolar amount of each comonomer

that is incorporated into the copolymer This may occur because the growing radical chains

will not add to its own monomer Therefore the opposite monomer will have to be added to

produce a growing chain and a perfectly alternating chain

When r1 gt 1 and r2 gt 1 both of the monomers want to add to themselves and in theory could

produce block copolymers But in actuality because of the short lifetime of the propagating

radical the product of such copolymerizations produces very undesirable heterogeneous

products that include homopolymers Therefore macroscopic phase separation could occur

and desirable physical properties such as transparency would not be achieved

172 Determination of Reactivity Ratios

Many methods have been used to estimate reactivity ratios of a large number of

comonomers94 The copolymer composition may not be independent of conversion This

means the disappearance of monomer one may be faster than the disappearance of monomer

two if monomer one is being incorporated into the copolymer at a faster rate and therefore it

has a larger reactivity ratio than monomer two

The approximation method95 is the simplest of the methods that has been used to calculate the

reactivity ratios of copolymer systems The method is based on the fact that r1 the reactivity

ratio of component one is mainly dependent on the composition of monomer two m2 that

has been incorporated into the copolymer at low concentrations of monomer two in the feed

M2 The expression is thus

94 Polic A L Duever T A and Penlidis A J Polym Sci Part A 36 (1998) 813 95 Tidwell P W and Mortimer G A Journal of Polym Sci Part A 3 (1965) 369

The value of the reactivity ratio for component one can be easily determined by only one

experiment but the value is only an approximation and does not provide any validity of the

estimated r1 In order to determine the amount of the comonomer that has been incorporated

into the copolymer various analytical methods must be used Proton Nuclear Magnetic

Resonance Carbon 13 NMR and Fourier Transform Infrared Spectroscopy are three sensitive

instruments that can determine the copolymer composition The approximation method is

limited when the reactivity ratio of one of the components in the system has a value of less

than 01 or greater than a value of 10

However the method does give good insight into the reactivity ratio values for many

copolymer systems The approximation of reactivity ratios can be easy and quick when using

this method of evaluation

The Mayo-Lewis intersection method91 96 uses a linear form of the copolymerization equation where r1 and r2 are linearly related

By using the equations m1M 22 m2M12 and (M2 M1)[(m1 m2) ndash 1] for the slope and intercept

respectively a plot can be produced for a set of experiments after the copolymer composition

has been determined The straight lines that are produced on the plot for each experiment

where r1 represents the ordinate and r2 represents the abscissa intersect at a point on the r1 vs

r2 plot The point where these lines meet is taken to be r1 and r2 for the system in study The

main advantage of this method is that it gives a qualitative observation of the validity of the

intersection area Over the whole range of possible copolymer compositions that were tested

more compact intersections better define the data However the method requires a visual

check of the data and a quantitative estimation of the error is impossible Therefore

weighting of the data is needed to determine the most precise values of r1 and r2

The Fineman-Ross linearization method97 uses another form of the copolymer equation

96 Davis T P Journal of Polym Sci Part A 39 (2001) 597 97 Fineman M and Ross S D Journal of Polymer Sci 5 (1950) 259

For this method by plotting G versus H for all the experiments one will obtain a straight line

where the slope of the straight line is the value for r1 and the intercept of the line is the value

for r2 This type of reactivity ratio determination has the same advantages and disadvantages

of the method described above however this treatment is a linear least squares analysis

instead of a graphical analysis The validity is only qualitative and the estimates of r1 and r2

can change with each experimenter by weighting the data in different ways Furthermore the

high and low experimental composition data are unequally weighted which produces large

effects on the calculated values of r1 and r2 Therefore different values of r1 and r2 can be

produced depending on which monomer is chosen as M158

A refinement of the linearization method was introduced by Kelen and Tudos98 99 100 by

adding an arbitrary positive constant a into the Fineman and Ross equation 47 This technique

spreads the data more evenly over the entire composition range to produce equal weighting to

all the data58 The Kelen and Tudos refined form of the copolymer equation is as follows

η = [ r1 + r2 α ] ξ minus r2 α (50)

η = G ( α + H ) (51)

ξ = H ( α + H ) (52)

By plotting η versus ξ a straight line is produced that gives ndashr2α and r1 as the intercepts on

extrapolation to ξ=0 and ξ=1 respectively Distribution of the experimental data

symmetrically on the plot is performed by choosing the α value to be (HmHM)12 where Hm

and HM are the lowest and highest H values respectively Even with this more complicated

monomer reactivity ratio technique statistical limitations are inherent in these linearization

methods101 102

98 Kelen T Tudos F and Turcsanyi B Polymer Bull 2 (1980) 71-76 99 Tudos F Kelen T Foldes-Berezsnich T and Turcsanyi B J Macromol SciPart A 10 (1976) 1513-1540 100 Tudos F and Kelen T J Macromol Sci Part A 16 (1981) 1283 101 Greenley R Z In Polymer Handbook 4th Edition Brandup J Immergut E H and Grulke E Eds John

Wiley New York (1999) 102 Greenley R Z In Polymer Handbook Part II 3rd Ed Brandup J Immergut E H and Grulke E Eds John

Wiley New York (1989) 153-265

OrsquoDriscoll Reilly et al103 104 determined that the dependent variable does not truly have a

constant variance and the independent variable in any form of the linear copolymer equation

is not truly independent Therefore analyzing the composition data using a non-linear

method has come to be the most statistically sound technique

The non-linear or curve-fitting method90 is based on the copolymer composition equation in

the form

This equation is based on the assumptions that the monomer concentrations do not change

much throughout the reaction and the molecular weight of the resulting polymer is relatively

high In order to determine reactivity ratios from the experimental data a graph must be

generated for the observed comonomer amount that was incorporated into the copolymer m1

versus the feed comonomer amount M1 for the entire range of comonomer concentrations

Then a curve can be drawn through the points for selected r1 and r2 values and the validity of

the chosen reactivity ratio values can be checked by changing the r1 and r2 values until the

experimenter can demonstrate that the curve best fits the data points

The main advantage of the reactivity ratio determination methods discussed thus far is the

results can be visually and qualitatively checked Disadvantages include a direct dependence

of the composition on conversion for most polymer systems and therefore low conversion

(eg instantaneous composition) is needed to determine the reactivity ratios Furthermore

extensive calculations are required but only qualitative measurements of precision can be

obtained Finally weighting of the experimental data for the methods to determine precise

reactivity ratios is hard to reproduce from one experimenter to another

Therefore a technique that allows the rigorous application of statistical analysis for r1 and r2

was proposed by Mortimer and Tidwell which they called the nonlinear least squares

method95105106107This method can be considered to be a modification or extension of the

curve fitting method For selected values of r1 and r2 the sum of the squares of the differences

between the observed and the computed polymer compositions is minimized

103 ODriscoll K F and Reilly P M Makromol Chem Makromol Symp 1011 (1987) 355 104 ODriscoll K F Kale L T Garcia-Rubio L H and Reilly P M J Polym Sci Polym Chem Ed 22

(1984) 2777 105 Hill D J T and ODonnell J H Makromol Chem Makromol Symp 1011 (1987) 375 106 Hill D J T Lang A P ODonnell J H and OSullivan P W Eur Polym J 25 (1989) 911 107 Hill D J T Lang A P and ODonnell J H Eur Polym J 27 (1991) 765-772

Using this criterion for the nonlinear least squares method of analysis the values for the

reactivity ratios are unique for a given set of data where all investigators arrive at the same

values for r1 and r2 by following the calculations Recently a computer program published by

van Herck108 109 allows for the first time rapid data analysis of the nonlinear calculations It

also permits the calculations of the validity of the reactivity ratios in a quantitative fashion110

The computer program produces reactivity ratios for the monomers in the system with a 95

joint confidence limit determination

The joint confidence limit is a quantitative estimation of the validity of the results of the

experiments and the calculations performed This method of data analysis consists of

obtaining initial estimates of the reactivity ratios for the system and experimental data of

comonomer charge amounts and comonomer amounts that have been incorporated into the

copolymer both in mole fractions Many repeated sets of calculations are performed by the

computer which rapidly determines a pair of reactivity ratios that fit the criterion wherein the

value of the sum of the squares of the differences between the observed polymer composition

and the computed polymer composition is minimized111 112 This method uses a form of the

copolymer composition equation with mole fractions of the feed It amounts to determining

the mole fraction of the comonomer that should be incorporated into the copolymer during a

differential time interval

For this equation F2 represents the mole fraction of comonomer two that was calculated to be

incorporated into the copolymer and f1 and f2 represent the mole fractions of each comonomer

that were fed into the reaction mixture The use of the Gauss-Newton nonlinear least squares

procedure predicts the reactivity ratios for a given set of data after repeating the calculations

so that the difference between the experimental data points and the calculated data points on a

plot of mole fraction of comonomer incorporated versus comonomer in the feed is reduced to

the minimum value113 114

108 van Herck A M J Chem Ed 72 (1995) 138 109 van Herck A M Manders B G Smulders W and Aerdts A Macromolecules 30 (1997) 322-323 110 Mott G Brendlein W and Braun D Eur Polym J 9 (1973) 1007-1012 111 Davis T P ODriscoll K F Piton M C and Winnik M A J Polym Sci Part C Polym Lett 27 (1989)

181 112 Davis T P ODriscoll K F Piton M C Winnik M A Macromolecules 23 (1990) 2113 113 Davis T P ODriscoll K F Piton M C and Winnik M A Polym Int 24 (1991) 65

18 Controlled Radical Polymerization

The development of new controlledliving radical polymerization processes such as Atom

Transfer Radical Polymerization (ATRP) and other techniques such as nitroxide mediated

polymerization and degenerative transfer processes including RAFT opened the way to the

use of radical polymerization for the synthesis of well-defined complex functional

nanostructures The development of such nanostructures is primarily dependent on self-

assembly of well-defined segmented copolymers This section describes the fundamentals of

ATRP relevant to the synthesis of such systems115

The main goal of macromolecular engineering is to carry out the synthesis (polymerization) in

such a way that it results in well-defined macromolecular products One of the ways to

achieve full control of the macromolecule (length sequence and regio- and stereoregularity)

would be to build it one monomer at a time with mechanisms in place facilitating selection of

an appropriate monomer and assuring its addition in proper orientation This of course has

been achieved in Nature in the process of protein synthesis through the use of sophisticated

macromolecular ldquonanomachineryrdquo (DNA RNA Most commonly used synthetic routes to

linear polymers are based on addition (chain) reactions which can be controlled only in

statistical terms through such parameters as initiatormonomer ratios monomerpolymer

reactivities monomer concentrations reaction medium etc The main strategy to achieve the

reasonable control of such reactionsrsquo products is through the synchronized growth of ldquolivingrdquo

chains ie chains which cease to grow only in the absence of a monomer Synchronization of

chain growth can be achieved fairly easily through rapid initiation Living chains grown in

such synchronized fashion exhibit relatively narrow molecular weight distributions (MWD)

their average molecular weights can be controlled simply by the duration of reaction Until

recently radical polymerization which covers the broadest range of monomers appeared to

be inherently uncontrollable due to the presence of fast chain termination of growing radicals

Thus although very useful in the synthesis of bulk commodity polymers where precise

control is not always essential radical polymerization has been hardly ever viewed as a tool to

precisely engineer macromolecules for well-defined functional nanostructures

114 Ghi P Y Hill D J T ODonnell J H Pomeroy P J and Whittaker A K Polymer Gels and Networks 4

(1996) 253 115 T Kowalewski RD McCullough and K Matyjaszewski Eur Phys J E 10 (2003) 5ndash16

This outlook shifted dramatically recently with the development of new controlledliving

radical polymerization processes such as Atom Transfer Radical Polymerization (ATRP)116

117 118 and other techniques such as nitroxide mediated polymerization119 and degenerative

transfer processes120 including reversible addition-fragmentation chain transfer (RAFT)121

With the availability of effective control mechanisms given its applicability to a broadest

range of monomers radical polymerization is now ready to assume the central role in

macromolecular engineering geared towards the development of well-defined functional

nanostructures

181 Fundamentals of ControlledLiving Radical Polymerization (CRP)

The great expectations for the controlledliving radical polymerization (CRP) have their

origins in the dominating position of the free radical technique by far the most common

method of making polymeric materials (nearly 50 of all polymers are made this

way)122123124This is due to the large number of available vinyl monomers (eg there are

nearly 300 different methacrylates available commercially) which can be easily

homopolymerized and copolymerized The advent of CRP enables preparation of many new

materials such as well-defined components of coatings (with narrow MWD precisely

controlled functionalities and reduced volatile organic compounds -VOCs) non ionic

surfactants polar thermoplastic elastomers entirely water soluble block copolymers

(potentially for crystal engineering) gels and hydrogels lubricants and additives surface

modifiers hybrids with natural and inorganic polymers various biomaterials and electronic

materials

The controlledliving reactions are quite similar to the conventional ones however the radical

formation is reversible Similar values for the equilibrium constants during initiation and

propagation ensure that the initiator is consumed at the early stages of the polymerization

116 J-S Wang and K Matyjaszewski J Am Chem Soc 117 (1995) 5614 117 K Matyjaszewski and J Xia Chem Rev 101 (2001) 2921 118 M Kamigaito T Ando and M Sawamoto Chem Rev 101 (2001) 3689 119 CJ Hawker AW Bosman and E Harth Chem Rev 101 (2001) 3661 120 SG Gaynor J-S Wang and K Matyjaszewski Macromolecules 28 (1995) 8051 121 RTA Mayadunne E Rizzardo J Chiefari YK Chong G Moad and SH Thang Macromolecules 32

(1999) 6977 122 K Matyjaszewski Ed ACS Symposium Series (2000) 685 123 K Matyjaszewski Ed ACS Symposium Series 2 (2000) 768 124 K Matyjaszewski and TP Davis Eds Handbook of radicalPolymerizationWiley-Interscience Hoboken

(2002)

generating chains which slowly and continuously grow as in a living process There are a

number of critical differences between conventional and controlledliving radical reactions

bull Perhaps the most important difference between the two approaches is the lifetime of

the propagating chains which is extended from 1 s to more than 1 h

bull The second major difference is the very significant increase in the initiation rate

which enables simultaneous growth of all the polymer chains

bull Termination processes cannot be avoided in CRPs Thus CRP is generally less precise

than the anionic polymerization Termination is the most dangerous chain breaking

reaction in CRPs Since it is a bimolecular process increasing the polymerization rate

increases the concentration of radicals and enhances the termination process

Termination also becomes more significant for longer chains and at higher conversion

However this process is somehow self tuned since termination is chain length

dependent

The key feature of the controlledliving radical polymerization is the dynamic equilibration

between the active radicals and various types of dormant species Currently three systems

seem to be most efficient nitroxide mediated polymerization (NMP) atom transfer radical

polymerization (ATRP) and degenerative transfer processes such as RAFT123 Each of the

CRPs has some limitations and some special advantages and it is expected that each

technique may find special areas where it would be best suited synthetically For example

NMP carried out in the presence of bulky nitroxides cannot be applied to the polymerization

of methacrylates due to fast β-H abstraction ATRP cannot yet be used for the polymerization

of acidic monomers which can protonate the ligands and complex with copper RAFT is very

slow for the synthesis of low MW polymers due to retardation effects and may provide

branching due to trapping of growing radicals by the intermediate radicals At the same time

each technique has some special advantages Terminal alkoxyamines may act as additional

stabilizers for some polymers ATRP enables the synthesis of special block copolymers by

utilizing a halogen exchange and has an inexpensive halogen at the chain end125 RAFT can

be applied to the polymerization of many unreactive monomers such as vinyl acetate126

182 Typical Features of ATRP

A successful ATRP process should meet several requirements

125 K Matyjaszewski DA Shipp J-L Wang T Grimaud and TE Patten Macromolecules 31 (1998) 6836 126 M Destarac D Charmot and X Franck ZSZ Macromol Rapid Comm 21 (2000) 1035

bull Initiator should be consumed at the early stages of polymerization to form polymers

with degrees of polymerization predetermined by the ratio of the concentrations of

converted monomer to the introduced initiator (DP = Δ[M][I]o)

bull The number of monomer molecules added during one activation step should be small

resulting in polymers with low polydispersities

bull The contribution of chain breaking reactions (transfer and termination) should be

negligible to yield polymers with high degrees of end-functionalities and allow the

synthesis of block copolymers

In order to reach these three goals it is necessary to select appropriate reagents and

appropriate reaction conditions ATRP is based on the reversible transfer of an atom or group

from a dormant polymer chain (R-X) to a transition metal (M nt Ligand) to form a radical (R)

which can initiate the polymerization and a metal-halide whose oxidation state has increased

by one (X-M n+1t Ligand) the transferred atom or group is covalently bound to the transition

metal A catalytic system employing copper (I) halides (Mnt Ligand) complexed with

substituted 2 2rsquo- bipyridines (bpy) has proven to be quite robust successfully polymerizing

styrenes various methacrylates acrylonitrile and other monomers116127 Other metal centers

have been used such as ruthenium nickel and iron based systems117 118 Copper salts with

various anions and polydentate complexing ligands were used such as substituted bpy

pyridines and linear polyamines The rate constants of the exchange process propagation and

termination shown in Scheme 11 refer to styrene polymerization at 110 C

Scheme 11

According to this general ATRP scheme the rate of polymerization is given by the following

equation

127 J-S Wang and K Matyjaszewski Macromolecules 28 (1995) 7901

Thus the rate of polymerization is internally first order in monomer externally first order

with respect to initiator and activator Cu(I) and negative first order with respect to

deactivator XCu(II) However the kinetics may be more complex due to the formation of

XCu(II) species via the persistent radical effect (PRE) The actual kinetics depend on many

factors including the solubility of activator and deactivator their possible interactions and

variations of their structures and reactivities with concentrations and composition of the

reaction medium It should be also noted that the contribution of PRE at the initial stages

might be affected by the mixing method crystallinity of the metal compound and ligand etc

One of the most important parameters in ATRP is the dynamics of exchange and especially

the relative rate of deactivation If the deactivation process is slow in comparison with

propagation then a classic redox initiation process operates leading to conventional and not

controlled radical polymerization Polydispersities in ATRP are defined by the following

equation when the contribution of chain breaking reactions is small and initiation is

complete

Thus polydispersities decrease with conversion p the rate constant of deactivation kd and

also the concentration of deactivator [XCu(II)] They however increase with the propagation

rate constant kp and the concentration of initiator [RX]o This means that more uniform

polymers are obtained at higher conversions when the concentration of deactivator in solution

is high and the concentration of initiator is low Also more uniform polymers are formed

when the deactivator is very reactive (eg copper(II) complexed by 2 2-bipyridine or

pentamethyldiethylenetriamine rather than by water) and monomer propagates slowly (styrene

rather than acrylate)

183 Controlled Compositions by ATRP

One of the driving forces for the development of a controlledldquo livingrdquo radical polymerization

is to allow for the copolymerization of two or more monomers128 This has been demonstrated

with ATRP by copolymerization of various combinations of styrene methyl or butyl acrylate

methyl or butyl methacrylate and acrylonitrile ATRP allows for the copolymerization of

these monomers using all feed compositions without loss of control of the polymerization 128 KD Davis K Matyjaszewski Adv Pol Sci 159 (2002) 1

this is in contrast to the use of 2266-tetramethylpiperidine-1-oxyl radical (TEMPO) which

must contain a significant amount of styrene as comonomer to retain control of the

polymerization This restriction does not apply to polymerizations mediated by new

nitroxides119 The statistical copolymers prepared by living polymerizations are not the same

as those prepared by conventional radical polymerizations due to the differences in

polymerization mechanism

During a copolymerization one monomer is generally consumed faster than the other

resulting in a constantly changing monomer feed composition during the polymerization the

preference is dependent on the reactivity ratios of the two (or more) monomers In

conventional radical polymerization where the polymer chains are continuously initiated and

are irreversibly terminated the change in monomer feed is recorded in the individual polymer

chains whose composition will vary from chain to chain depending on when the chain was

formed ie at the beginning or near the end of the reaction However since ATRP is a

controlledldquolivingrdquo polymerization system the vast majority of polymer chains does not

irreversibly terminate but grow gradually throughout the polymerization The change in

monomer feed is recorded in the polymer chain itself and not from chain to chain The drifting

of composition along the polymer chain is expected to yield gradient copolymers with novel

properties129 Conventional free radical polymerization methods are generally not suitable for

synthesizing star shaped polymers due to the occurrence of undesirable radical coupling

reactions During a ldquocore-firstrdquo synthesis this would lead to coupling of the growing polymer

arms and ultimately result in a cross-linking of the star macromolecules

Block copolymers can be formed by addition of a second vinyl monomer to a macroinitiator

which contains halide groups that participate in the atom transfer process Most notably this

has been demonstrated by successive addition of a second monomer at the end of the

polymerization of a first monomer by ATRP In this manner AB and ABA block copolymers

have been prepared with various combinations of styrene acrylates methacrylates and

acrylonitrile It is very important to select the right order of monomer addition For example

polyacrylates can be efficiently initiated by the poly (methyl methacrylate)- BrCuBrL

system However the opposite is not true because concentration of radicals and overall

reactivity of acrylates is generally too low to efficiently initiate MMA polymerization

Halogen exchange comes to the rescue bromoterminated polyacrylate in the presence of

129 K Matyjaszewski MJ Ziegler SV Arehart D Greszta and T Pakula J Phys Org Chem 13 (2000) 775

CuClL is an efficient initiator for MMA polymerization due to reduced polymerization rate

of PMMA-Cl species which are predominantly formed after the exchange process130 131 132

Scheme 12

To conclude atom transfer radical polymerization is a robust method for preparing well-

defined polymers and novel materials with unique compositions and architectures Although

significant progress has been made in the past few years since the development of ATRP

continuous research on the better mechanistic understanding of ATRP and the preparation of

more efficient catalyst systems to yield more well-defined polymers and polymerize new

monomers is needed The syntheses of new materials need to be optimized and their

properties should be studied

It is anticipated that the new controlledliving techniques will help to provide many new well-

defined polymers via macromolecular engineering

130 DA Shipp J-L Wang K Matyjaszewski Macromolecules 31 (1998) 8005 131 K Matyjaszewski DA Shipp GP McMurtry SG Gaynor T Pakula J Polym Sci A 38 (2000) 2023 132 Braunecker WA and Matyjaszewski K Prog Polym Sci (2007) 3293

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7022-7028 73 Ruokolainen J Saariaho M Ikkala O ten Brinke G Thomas E L Torkkeli M and Serimaa R

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551 75 Roos S Muumlller A H E Kaufmann M Siol W and Auschra C Quirk R P Ed ACS Symp Ser (1998)

696-208 76 Schulz G O and Milkovich R Journal of Appl Polym Sci 27 (1982) 4773 77 Xu G X and Lin S G Journal of Macromol SciRev Macromol Chem Phys C34 (1994) 555-606 78 Mukherjee A K and Gupta B D J Journal of Macromol Sci Chem A19 (1983) 1069-1099 79 Boutevin B Robin J J and Serdani A Eur Polym Journal 28 (1992) 1507 80 Liu Y Lee J Y Kang E T Wang P and Tan K L React Funct Polym 47 (2001) 201-213 81 Wang X-S Luo N Ying S-K Polymer 40 (1999) 4515-4520 82 Furuhashi H Kawaguchi S Itsuno S and Ito K Colloid Polym Sci 227 (1997) 275 83 Capek I Adv Polym Sci 1 (1999) 145 84 Nguyen SH Berek D Capek I J Polym Sci submitted for publication 85 Painter P C and Coleman M M Fundamentals of Polymer Science Technomic Publishing Inc Lancaster

PA (1997) 86 Moad G Solomon D H The Chemistry of Free Radical Polymerization Pergamon Press New York (1995) 87 Rosen S L Fundamental Principles of Polymeric Materials John Wiley and Sons New York (1993) 88 Mark H F Bikales N M Overberger C G and Menges G Eds Wiley-Interscience New York Vol 4

(1986) 192-233 89 Staudinger H Schneiders J Ann Chim 541 (1939) 151 90 Alfrey T Bohrer J Jand Mark H Copolymerization Interscience New York (1952) 91 Mayo F R and Lewis F M J Am Chem Soc 66 (1944) 4594 92 Walling C Free Radicals in Solution Wiley New York Chap 4 (1957) 93 Flory P J Principles of Polymer Chemistry Cornell University Press Ithaca (1953) 94 Polic A L Duever T A and Penlidis A J Polym Sci Part A 36 (1998) 813 95 Tidwell P W and Mortimer G A Journal of Polym Sci Part A 3 (1965) 369

96 Davis T P Journal of Polym Sci Part A 39 (2001) 597 97 Fineman M and Ross S D Journal of Polymer Sci 5 (1950) 259 98 Kelen T Tudos F and Turcsanyi B Polymer Bull 2 (1980) 71-76 99 Tudos F Kelen T Foldes-Berezsnich T and Turcsanyi B J Macromol SciPart A 10 (1976) 1513-1540 100 Tudos F and Kelen T J Macromol Sci Part A 16 (1981) 1283 101 Greenley R Z In Polymer Handbook 4th Edition Brandup J Immergut E H and Grulke E Eds John

Wiley New York (1989) 153-265 103 ODriscoll K F and Reilly P M Makromol Chem Makromol Symp 1011 (1987) 355 104 ODriscoll K F Kale L T Garcia-Rubio L H and Reilly P M J Polym Sci Polym Chem Ed 22

(1984) 2777 105 Hill D J T and ODonnell J H Makromol Chem Makromol Symp 1011 (1987) 375 106 Hill D J T Lang A P ODonnell J H and OSullivan P W Eur Polym J 25 (1989) 911 107 Hill D J T Lang A P and ODonnell J H Eur Polym J 27 (1991) 765-772 108 van Herck A M J Chem Ed 72 (1995) 138 109 van Herck A M Manders B G Smulders W and Aerdts A Macromolecules 30 (1997) 322-323 110 Mott G Brendlein W and Braun D Eur Polym J 9 (1973) 1007-1012 111 Davis T P ODriscoll K F Piton M C and Winnik M A J Polym Sci Part C Polym Lett 27 (1989)

181 112 Davis T P ODriscoll K F Piton M C Winnik M A Macromolecules 23 (1990) 2113 113 Davis T P ODriscoll K F Piton M C and Winnik M A Polym Int 24 (1991) 65 114 Ghi P Y Hill D J T ODonnell J H Pomeroy P J and Whittaker A K Polymer Gels and Networks 4

(1996) 253 115 T Kowalewski RD McCullough and K Matyjaszewski Eur Phys J E 10 (2003) 5ndash16 116 J-S Wang and K Matyjaszewski J Am Chem Soc 117 (1995) 5614 117 K Matyjaszewski and J Xia Chem Rev 101 (2001) 2921 118 M Kamigaito T Ando and M Sawamoto Chem Rev 101 (2001) 3689 119 CJ Hawker AW Bosman and E Harth Chem Rev 101 (2001) 3661 120 SG Gaynor J-S Wang and K Matyjaszewski Macromolecules 28 (1995) 8051 121 RTA Mayadunne E Rizzardo J Chiefari YK Chong G Moad and SH Thang Macromolecules 32

(2002) 125 K Matyjaszewski DA Shipp J-L Wang T Grimaud and TE Patten Macromolecules 31 (1998) 6836 126 M Destarac D Charmot and X Franck ZSZ Macromol Rapid Comm 21 (2000) 1035 127 J-S Wang and K Matyjaszewski Macromolecules 28 (1995) 7901 128 KD Davis K Matyjaszewski Adv Pol Sci 159 (2002) 1

129 K Matyjaszewski MJ Ziegler SV Arehart D Greszta and T Pakula J Phys Org Chem 13 (2000) 775 130 DA Shipp J-L Wang K Matyjaszewski Macromolecules 31 (1998) 8005 131 K Matyjaszewski DA Shipp GP McMurtry SG Gaynor T Pakula J Polym Sci A 38 (2000) 2023 132 Braunecker WA and Matyjaszewski K Prog Polym Sci (2007) 3293

CHAPTER II Synthesis and Characterization of

Macromonomers

21 Introduction

Cationic ring opening polymerization of DXL proposed by Franta and Reibel133 results in

linear polymeric chains thereby preventing formation cyclic oligomers through cationic

polymerization of cyclic acetals15 17In fact the reaction of DXL in the presence of an

unsaturated alcohol (2-HPMA) results in a functionalized linear PDXL macromonomer

carrying at one or both ends an unsaturated system supported by the methacryloyl group of

the alcohol The synthesis of α ω-dihydroxy-PDXL chains is based on the activated monomer

mechanism44 Franta et al have established that when DXL is polymerized by strong protonic

acids such as triflic acid in the presence of a diol the PDXL chains are essentially linear and

carry end-standing OH functions It has been shown that the amount of cyclic species formed

is negligible that the dispersity is on the order of 14 and that the molecular weight of the

linear polymers is governed by the ratio of reacted monomer to transfer agent and is generally

well controlled up to 10 000 gmol

De Clercq and Goethals have reported the preparation of poly (13dioxolane)

bismacromonomers by copolymerization with MMA and provided the possibility to prepare

polymer networks containing PDXL segments134 135 PDXL based hydrogels have been

obtained in most cases by free radical copolymerization with comonomers such as acrylic

acid acrylamide and N-isopropylacrylamide134 136 137 styrene and butyl acrylate138

Hydrogels have received increasing attention for biomedical applications such as drug

delivery immobilization of enzymes dewatering of protein solutions and contact lenses139

133 EFranta JRefai CDurand LReibel MakromolChem Makromol Symp32 (1990) 169-174 134 J Du X Ding Z Zheng Y Peng European Polymer Journal 38 (2002) 1033-1037 135 EJ Goethals and al Makromol Chem Makromol Symp 48 (1991) 427-429 136 Juan Du Yuxing Peng Xiaobin Ding Colloid Polym Sci 281 (2003) 90-95 137 J Du YPeng T Zhang X Ding Z Zheng Journal of Applied Polym Sci 83 (2002) 1678-1682 138 RR De Clercq EJ Goethals Macromolecules 25 (1992) 1109-1113 139 Caihua Ni Xiao-Xia Zhu European Polymer Journal 40 (2004)1075-1080

140 These materials and are widely used in areas like baby diapers solute separation soil for

agriculture and horticulture absorbent pads etc139 Hydrogels are defined as hydrophilic

polymer networks which have a high capacity to adsorb a substantial amount of water which

have been proposed as protein releasing matrices The high water content ensures a good

compatibility with entrapped proteins as well as with surrounding tissue141 Even though a

number of applications are currently being pursued using hydrogel very little is known about

the mechanical behavior that describes the various physical processes in hydrogels142 Over

the last decade most interests have been emphasized on the synthesis of polymers containing

polyacetal segments because of the ease of degradation of these polymers under mild

conditions by treatment with a trace of acid134 143 Poly (1 3 dioxolane) is a hydrophilic non-

ionic polymer which like poly (ethylene oxide) is appreciably soluble in water but much

more sensitive to acidic degradation because of the presence of acetal groups in the chains144

In this chapter we report the synthesis of the functionalized poly (13dioxolane)

macromonomers which have been used for the preparation of PDXL hydrogel and

amphiphilic graft copolymers In the second part of this chapter we have focused on a

detailed study of the properties of the resulting hydrogel in terms of swelling behavior in

different organic solvents and viscoelastic properties determined by rheological measurements

in both the steady shear and oscillatory experiments

22 Experimental

221 Chemicals and Purification

a) Solvents and Reagents

bull Tetrahydrofuran (THF C4H8O MW 7211 bp 65-67degC d 0885-0890)

Major impurities in THF include inhibitors peroxides and water To remove these

impurities commercial THF (Prolabo product) was refluxed over a small amount of

sodium (Aldrich 40 wt in paraffin) and benzophenone (Aldrich 99) under a nitrogen

atmosphere at 66degC The anhydrous state of THF was indicated by a deep purple

140 B Yildiz B Isik M Kis Reactive amp Functional Polymers 52 (2002) 3-10 141 SJde Jong and al Journal of controlled release 72 (2001) 47-56 142 S K De and al Journal of Micro electromechanical Systems 11 (2002) 544-554 143 A Benkhira E Franta J Franccedilois Macromolecules 25 (1992) 5697-5704 144 K Naragui N Sahli M Belbachir E Franta PJ Lutz Polymer Int 51 (2002) 912-922

complex formed from sodium and benzophenone Pure THF was distilled from this deep

purple solution immediately prior to use

bull Dichloromethane (CH2Cl2 MW 8493 bp 40degC d 1325)

Dichloromethane (Prolabo 999) was dried by stirring over CaH2 for 24 h and then

distilled under a N2 atmosphere to remove impurities Purified dichloromethane was

stored under nitrogen over molecular sieve

bull 2-hydroxypropyl methacrylate (2-HPMA) (MW 14417 bp 240degC d 1028)

2-HPMA of commercial grade was purchased from Acros stabilized with 200 ppm

hydroquinone monomethyl ether Then it was stored over molecular sieve

bull n-Hexane 99 (C6H14 MW 8618 bp 68-70degC d 0658-0662) Stored under

nitrogen over molecular sieve

bull Trifluoromethanesulfonic acid (triflic acid Aldrich) was used as received

bull 22-azobis(2-methylpropioyonitrile(IUPAC-name)Azobisisobutyronitrile (AIBN)

((CH3)2C(CN)N=NC(CH3)2CN) (MW 16421 mp 104degC)

The free radical initiator AIBN was obtained from Aldrich Chemicals AIBN is a white

powder was purified by recrystallization from methanol

b) Monomer

bull 1 3 dioxolane (DXL) (MW 7408 bp 78degC d 106)

The monomer DXL of commercial grade was purchased from Acros DXL was kept

under KOH for two and up to three days to remove any peroxide and stabilizer traces

and then purified by distillation over CaH2 under a N2 atmosphere prior to

polymerization

All chemicals were kept over molecular sieve before use

222 Reaction apparatus

All polymerization experiments were performed with a clean 250 ml three neck round bottom

flask A condenser was used on one of the necks of the flask in order to condense any

monomers that might otherwise possibly escape A magnetic bar was used to stir the solution

at a constant speed in order to assure even distribution of monomer and initiator

concentrations throughout the entire volume of solution A rubber septum was used to cover

one of the three necks

In the case of free radical polymerization reactions a thermocouple was also fitted to the

reaction vessel to monitor the temperature of the reaction The thermocouple regulated the

temperature at a constant 70degC throughout the reaction

223 Synthesis of Poly (13-dioxolane) Macromonomers

Methacrylate-terminated PDXL macromonomers were synthesized by Cationic ring-opening

polymerization which was carried out in 10 ml dichloromethane with triflic acid as initiator at

room temperature under nitrogen for 24 h in the presence of 2-hydroxypropyl methacrylate

(2-HPMA) as transfer agent 20 ml of DXL monomer was added The feed molar ratios

[DXL] [2-HPMA] are reported in Table1 as well as the molecular characteristics of the

obtained macromonomers The amount of the acid used was 20 μl After reaction the

resulting solution is poured into THF Then the product is purified by re-precipitation from

THF solution with a large excess of hexane and the obtained polymer was dried under

vacuum at room temperature The yield was checked by gravimetric determination and found

to be about 80

224 Synthesis of Poly (13-dioxolane) Hydrogel Network

The functionalized PDXL macromonomer taken for the preparation of PDXL netwok was

(FPP2) macromonomer with a theoretical average molecular weight of Mnth =2000

The macromonomer (1g) was polymerized by free radical polymerization in 10 ml of THF

using 2 2-azobisisobutyronitrile (AIBN) (001g) as initiator under a nitrogen atmosphere

The polymerization was carried out at 70degC for 24h A piece of hydrogel was obtained The

product was extracted with ethanol to remove unreacted macromonomers and then dried

under vacuum

23 Characterization Techniques

231 Raman Spectroscopy

Raman spectroscopy is used to study and analyse the structure of the macromonomers

The experiments were performed on a Dilor XY 800 spectrophotometer The detector was a

charge-coupled device (CCD) An argon laser pump beam (power density of 100 mW) has

been focused onto the sample through a microscope The working wavelength was chosen as

λ = 5145 nm In our experiments we explored the spectral range between 200 and 3700 cm-1

with a spectral resolution of 2 cm-1

232 1H-NMR Spectroscopy

Proton Nuclear Magnetic Resonance Spectroscopy (1H NMR) was used for structural analysis

and molecular weight of polymers and macromonomers Proton NMR spectra were obtained

using a high field 400Mhz Advance Bruker spectrometer

All of the 1H NMR samples were dissolved in deuterated chloroformThe chloroform

reference peak at 724 ppm was to ensure accuracy of peak assignments The integrals of the

peaks were used for the calculations to determine the Mw of the macromonomers

233 Size Exclusion Chromatography

Size Exclusion Chromatography (SEC) represents a chromatographic method widely used in

the analysis of polymer average molecular weights and molecular weight distributions SEC

Measurements were performed at 40degC on a Waters 2690 instrument equipped with UV

detector (Waters 996 PDA) coupled with a Differential Refractometer (ERC - 7515 A) and

four Styragel columns (106 105 500 and 50degA) THF is employed as eluent with a flow rate

of 10 mlmin Polystyrene standard samples were used for calibration

234 Swelling Measurements

In order to investigate the swelling behavior the measurement of the swelling ratio of the

polymer network is obtained from a gravimetric method in which small pieces of hydrogel

were immersed solvents such as CH2Cl2 and THF for 24 hours at room temperature (23degC)

until swelling equilibrium was reached ie when the gel thickness became essentially

constant The samples were removed from the solvents and carefully weighed (Ws) Then the

samples let to deswell and weighed every 5 min during in order to determine the swelling

kinetics in the solvents The swelling equilibrium was reached after 5 hours Afterwards the

gel was left to dry for 24 hours at room temperature until constant weight was attained and the

dry weight (Wd) was determined and the swelling ratio was calculated from equation

SR = ( ) 100timesminusWd

WdWs (57)

Where SR is equilibrium swelling ratio Ws and Wd are the sample weights in swollen and dry

states respectively

235 Rheological Measurements

Steady shear and oscillatory measurements have been performed on a stress imposed

rheometer Rheo-Stress-100 (RS100) from Haake used with a coneplate geometry (20 mm

diameter an angle of 4deg gap 2 mm)The imposed stress of 100 Pa during 30 seconds and a

frequency of 1Hz were applied while the strain was monitored The measurements have been

performed on swollen and unswollen samples The elastic (G) and the loss (G) moduli are

measured in linear viscoelastic region In the oscillatory experiments the frequency

dependence of both Grsquo and G is obtained at a constant strain All rheological measurements

were carried out at room temperature (23 degC)

24 Results and Discussion

241 Structural Characterization of Macromonomers

1 3 dioxolane (DXL) belongs to the class of heterocyclic monomers containing acetal

with the propagation reaction the active sites at the growing polymer end ie cyclic

during the polymerization The synthesis of α ω-dihydroxy-PDXL chains is based on the

activated monomer mechanism44 Franta et al have established that when DXL is polymerized

by strong protonic acids such as triflic acid in the presence of a diol the PDXL chains are

essentially linear and carry end-standing OH functions It has been shown that the amount of

cyclic species formed is negligible that the dispersity is on the order of 14 and that the

molecular weight of the linear polymers is governed by the ratio of reacted monomer to

transfer agent and is generally well controlled up to 10 000 gmol

The preparation of the methacryloyl-terminated PDXL macromonomers via Activated

Monomer mechanism proposed by Franta and Reibel44 133 using an unsaturated alcohol (2-

HPMA) as a transfer agent results in linear polymeric chains thereby preventing formation of

cyclic oligomers through cationic polymerisation of cyclic acetals15 17 They were all prepared

at the same reaction conditions The synthetic route of functionalized PDXL macromonomers

is shown in scheme13

Scheme 13 Structures of PDXL macromonomer species54

According to this mechanism it is possible to prepare macromonomers ie PDXL chains

carrying polymerizable double bonds at their ends Nevertheless because of the

transacetalization reactions a mixture of products is obtained

A is the most abundant compound it corresponds to 50 to 60 weight wise54 It is a

macromonomer

B corresponds to 20 to 25 weight wise It is a bis-macromonomer It carries two

methacryloyl functions corresponding to transacetalization of R-OH and DXL

C corresponds to 20 to 25 weight wise It carries no methacryloyl function but two

hydroxyl groups It is a α ω-dihydroxy-PDXL

These 3 species A B and C stem from scrambling reactions that are typical with cyclic

acetals54

The characterization of these materials is based on structure and molecular weight

determination For instance the PDXL macromonomers carried at one of their ends a double

bond afforded by the methacryloyl group The latter was checked by Raman and 1H-NMR

spectroscopy All macromonomers prepared displayed functionality close to unity which

makes them suitable for the synthesis of graft copolymers

Raman spectroscopy is used to study and analyse the structure of the macromonomers The

aim of this study is to check the formation of linear polymer chains as well as the termination

with methacryloyl groups The spectra obtained exhibit two intense Raman bands at 800 to

900 cmP

-1 and 2700 to 3000 cmP

-1 regions and a series of small other peaks for all samples as

shown in figure 1 The most intense band (2700 ndash 3000 cmP

-1) is assigned to the aliphatic

stretching vibration of CH in the polyacetal chain Symmetric COCOC stretching frequencies

of aliphatic acetals fall in typical regions of 1115-1080cmP

-1 and 870-800 cmP

-1 145 and are

responsible for intense Raman bands In the low frequency region there are three very

characteristic Raman bands in the 600 ndash 550 cmP

-1 540 ndash 450 cmP

-1 and 400 ndash 320 cmP

-1 ranges

which are assigned to COCOC deformations145 146 Also the acetals have strong multiple

bands in the region of 1160ndash1040 cmP

-1 as noticed on the Raman spectra involving the C-O

stretching modes In addition to this the O-CH-O group gives rise to a band at 1350 ndash1325

-1 for C-H deformation Other intense Raman bands are observed in the region of 3000 ndash

2700 cmP

-1 Below 3000 cmP

-1 the corresponding frequencies are assigned to the aliphatic C-H

stretching modes145 The methoxy group is detected in the region of 2835 ndash 2780 cmP

Figure 1 Raman spectra of methacrylic-terminated PDXL macromonomers (FPP2 FPP15 and

145 Daimay Lin-Vien Norman B Colthup William G Fateley and Jeanette G Grasselli The Handbook of IR

and Raman Characteristic Frequencies of Organic Molecules United Kingdom Ed by Academic Press Limited London (1991)

146 Norman B Colthup and Stephen E Wilberly Introduction to Infrared and Raman Spectroscopy 3rd Edition AP Limited London (1964)

As far as the presence of the methacryloyl group in the polymeric chain is important bands

have been observed at 1640 cmP

-1 which corresponds to C=C bonds The carbonyl compounds

absorb strongly within 1900 ndash1550 cmP

-1 region145 146 the spectra show a C=O bond absorption

found at 1720 cmP

-1 In the region of 1340 ndash1250 cmP

-1 the methacrylate bands are observed

Broad absorption is found near 3500 cm -1 owing to stretching of the OH bonds OH

deformation bands are found at 1400 cmP

-1P and 1340 cmP

-1 This observation indicates that both

methacrylic and ndashOH groups are present and eventually the resulting product is a mixture of

the three species as shown in the scheme above

Typical 1H-NMR spectrum of PDXL macromonomer shown in figure 2 exhibits the expected

resonance assigned to the methoxy protons (477 ppm) and OCH2CH2O protons at (374

ppm) Two signals corresponding to =CH2 were observed at (612 ndash 614 ppm) and (557 ndash

559 ppm) Therefore the spectrum confirmed the chemical structure HO[CH2CH2OCH2O]nR

of methacryloyl- terminated PDXL macromonomer

Figure 2 1H-NMR spectrum of PDXL macromonomer CDCl3 (sample FPP2)

242 Molecular Weight Determination

Besides the structure 1H-NMR enables us to determine the number-average molecular weight

(Mn) In the calculation of the latter the methacryloyl end group was included The

polydispersity and index MwMn and the number-average molecular weight were obtained

from SEC measurements Table 1 summarizes these values It can be seen that Mn (SEC) and

Mn (NMR) are very close to each other for all macromonomer samples and are in agreement

with the theoretical values predicted from calculations Under our polymerization conditions

the polydispersity index is 16 for all samples

Table 1 Characteristics of PDXL macromonomers prepared at different degrees of

polymerization

Sample Dp Mnth MnSEC MnRMN MwMn f (a)

FPP1 135 1000 1120 1160 16 097

FPP15 2025 1500 1540 1550 16 099

FPP2 270 2000 2040 2100 16 097

Dp degree of polymerization = [DXL] [2HPMA]

a functionality of macromonomers (methacryloyl end groups molecule)

243 Swelling of Poly (13 Dioxolane) Hydrogel

The synthesized PDXL hydrogel has been studied in terms of swelling and rheological

behaviors The degree of swelling and the rate of swelling of the hydrogel are studied It is

known that hydrogel can swell in several solvents but at different degree of swell according to

many factors related to the nature of the solvents and the type of polymer-solvent interactions

It was found that the solubility parameter of the solvents (δ) had a great effect on swelling

degree For instance hydrogels can swell fast in CH2Cl2 (δ = 976 cal cm12 -32) and reached

equilibrium within no more than an hour However it will take about more than 20 h to reach

equilibrium in CH3 OH (δ = 145 cal cm12 -32) It was known that the polymer can reach

greatest swelling degree when the solubility parameter of the polymer is close to that of the

solvents The solubility parameter of PDXL is about 93 cal cm 12 -32 134 The swelling has been

examined in THF and CH2Cl2 for PDXL hydrogel It has been observed that the swelling

equilibrium is reached after almost 5 hours of swelling for all samples in both solvents The

results show that THF (δ = 952 cal cm12 -32)147 swells the hydrogel to the greatest degree

compared to CH2Cl2 as shown in figure 3 However CH2Cl2 molecules provide less swelling

147 Allan F M Barton ldquoHandbook of Solubility Parametersrdquo CRC Press (1983)

capacity than in THF On the basis of the experiment The PDXL hydrogel reached high

swelling degree due to its solubility parameter is much closer to that of THF

0 200 400 600 800 1000 1200 1400 16000

THF CH2Cl2

Time (min)

Figure 3 Swelling kinetics of PDXL hydrogel in two different solvents CH2 Cl2 (solid

squares) and in THF (hollow squares)

244 Viscoelastic Behavior

Rheological measurements were performed on rheometer in the Cone and Plate geometry

Both steady shear and oscillatory experiments were carried out The dynamic storage and loss

moduli G and G were examined at room temperature (23 degC)

Many attempts have been carried to extend the elasticity theory to swollen gels148 149 Based

on this approach all measurements have been performed on both swollen and unswollen

hydrogel samples for the purpose of comparison so that to examine the mechanical properties

even in swollen state For instance Flory and Rehner recognized the swelling phenomenon

exhibited by cross-linked polymers when exposed to certain solvents and related the modulus

of elasticity of a swollen cross-linked polymer network to an unswollen network150 Figure 4

illustrates the strain dependence of G and G for swollen and unswollen samples

148 N W Taylor and E B Bagley Journal of Polym Sci Polymer Physics 13 (1975) 1133-1144 149 H N Nae and W W Reichert Reologica Acta 31 (1992) 351-360 150 BD Johnson DJ Niedermaier WC Crone J Moorthy and DJ Beebe Society for Experimental

Mechanics SEM Annual Conference Proceedings (2002)

10-5 10-4 10-3 10-2 10-1 100 101 102101

Guns Guns Gs Gs

Figure 4 Strain dependence of the elastic modulus Grsquo (circles) and of the viscous modulus

Grdquo(triangles) for two samples of unswollen hydrogel (solid symbols) and swollen hydrogel

(hollow symbols)

The moduli are measured as a function of strain at a constant frequency It appears that the

linear viscoelastic region is observed while the strain is increasing in either state which

indicates that the internal structure of the samples has not been disrupted when deformed

This leads to reveal that the gel is strain resistant in swollen and unswollen states and within a

large strain range the hydrogel retains its elasticity as shown in figure 4 where the linear

viscoelastic region extends to almost 02

The frequency dependence of G and G is shown in figure 5 similarly for swollen and

unswollen hydrogels The system behaves typically like a gel as it can be noticed that the

elastic component G (storage modulus) is far greater than the viscous component G (loss

modulus)151 Based on these results the hydrogel exhibits extreme elasticity at low

frequencies

151 C Chassenieux J Fundin G Ducouret and I Iliopoulos Journal of Molecular Structure 554 (2000) 99-108

100 101

Gs Guns Gs GunsG

ω (rads)

Figure 5 Frequency dependence of Grsquo(circles) and Grdquo(triangles) for swollen hydrogel

(hollow symbols) and unswollen hydogel (solid symbols)

Finally figure 6 illustrates the complex viscosity profiles another parameter of

viscoelasticity which measures the magnitude of the total resistance to a dynamic shear

Again this property has not been affected by swelling since the results show similar behavior

for swollen and unswollen states It decreases sharply as frequency increases which

characterizes the samples degree of viscoelasticity at various time scales Therefore from the

results discussed above the hydrogel network is elastic and stable even in the swollen state

thereby possessing very good mechanical properties

100 101 102 103

η unswollen η swollen

ηlowast (P

ω (rads)

Figure 6 Frequency dependence of the complex viscosity η for unswollen hydrogel (solid

squares) and swollen hydrogel (hollow triangles)

Conclusion

The hydrogel properties were discussed in terms of swelling and viscoelastic

behaviors The hydrogel has combined special properties Its swelling behaviour in the

solvents was dependent on the solubility parameter of both solvents and hydrogel

Rheological measurements were successful when used in order to study the viscoelastic

behavior of the hydrogel of pure PDXL in swollen and unswollen states The Strain

dependence of G and G for both samples shows linear viscoelastic region and allows to

determine the yield stress Same conclusions can be given concerning the frequency

dependence of complex viscosity the swelling does not affect this property The results reveal

a perfect elastic and resistant hydrogel in other words the viscoelastic properties have not

been so much affected by swelling They may be particularly useful in the design of improved

microfluidic devices that utilise the relationship between swelling and strain This kind of

material can be potentially used in biosystems such as intelligent drug delivery systems

References

133 EFranta JRefai CDurand LReibel MakromolChem Makromol Symp32 (1990) 169-

174 134 J Du X Ding Z Zheng Y Peng European Polymer Journal 38 (2002) 1033-1037 135 EJ Goethals and al Makromol Chem Makromol Symp 48 (1991) 427-429 136 Juan Du Yuxing Peng Xiaobin Ding Colloid Polym Sci 281 (2003) 90-95 137 J Du YPeng T Zhang X Ding Z Zheng Journal of Applied Polym Sci 83 (2002)

1678-1682 138 RR De Clercq EJ Goethals Macromolecules 25 (1992) 1109-1113 139 Caihua Ni Xiao-Xia Zhu European Polymer Journal 40 (2004)1075-1080 140 B Yildiz B Isik M Kis Reactive amp Functional Polymers 52 (2002) 3-10 141 SJde Jong and al Journal of controlled release 72 (2001) 47-56 142 S K De and al Journal of Micro electromechanical Systems 11 (2002) 544-554 143 A Benkhira E Franta J Franccedilois Macromolecules 25 (1992) 5697-5704 144 K Naragui N Sahli M Belbachir E Franta PJ Lutz Polymer Int 51 (2002) 912-922 145 Daimay Lin-Vien Norman B Colthup William G Fateley and Jeanette G Grasselli The

Handbook of IR and Raman Characteristic Frequencies of Organic Molecules United

Kingdom Ed by Academic Press Limited London (1991) 146 Norman B Colthup and Stephen E Wilberly Introduction to Infrared and Raman

Spectroscopy 3rd Edition AP Limited London (1964) 147 Allan F M Barton ldquoHandbook of Solubility Parametersrdquo CRC Press (1983) 148 N W Taylor and E B Bagley Journal of Polym Sci Polymer Physics 13 (1975) 1133-

1144 149 H N Nae and W W Reichert Reologica Acta 31 (1992) 351-360 150 BD Johnson DJ Niedermaier WC Crone J Moorthy and DJ Beebe Society for

Experimental Mechanics SEM Annual Conference Proceedings (2002) 151 C Chassenieux J Fundin G Ducouret and I Iliopoulos Journal of Molecular Structure

554 (2000) 99-108

CHAPTER III Synthesis and Characterization of Copolymers

31 Introduction

Amphiphilic block and graft copolymers consisting of hydrophilic and hydrophobic parts

have been subjects of numerous studies within which block and graft copolymers containing

hydrophilic polyoxyethylene segments and other hydrophobic segments have attracted much

attention because polyoxyethylene segments are not only hydrophilic but also nonanionic

and crystalline and can complex monovalent metallic cations Graft copolymers offer all

properties of block copolymers but are usually easier to synthesize Moreover the branched

structure leads to decreased melt viscosities which is an important advantage for processing

Depending on the nature of their backbone and side chains they give rise to special properties

in selective solvents at surfaces as well as in the bulk owing to microphase separation

morphologies12 They can be used for a wide variety of applications such as polymeric

surfactants electrostatic charge reducers compatibilizers in polymer blends polymeric

emulsifiers controlled wet ability and so on152 153 In order to prepare graft copolymers with

well-defined structure one can utilize the macromonomer technique (grafting through

technique) Well-defined structure graft copolymers are synthesized by copolymerization of

macromonomers with low molecular weight comonomers6 It allows the control of the

polymer structure which is given by three parameters (i) chain length of side chains which

can be controlled by the synthesis of the macromonomer by living polymerization (ii) chain

length of backbone which can be controlled in a living copolymerization (iii) average

reactivity ratio of the low-molecular weight monomer However the distribution of spacings

may not be very easy to control due to the incompatibility of the polymer backbone and the

macromonomers154 As pointed out in recent publication reviews155 there is a complex

interplay of factors that govern the reactivities in copolymerizations involving

macromonomers When different comonomers are copolymerized with the same it seems that

the degree of interpenetration between the macromonomer and the propagating copolymer 152 Fernandez-Garcia M Luis de la Fuente J Cerrada ML and Madruga EL Polymer 43 (2002) 3173-3179 153 Hou SS and Kuo PL Polymer 42 (2001) 2387-2394 154 Roos SG Muller Axel H E and K Matyjaszewski Macromolecules 32 (1999) 8331-8335 155 Meijs F and Rizzardo E JMacromol Sci Rev Macromol ChemPhys 33 (C30) (1990) 305

backbone plays the major role in the measured reactivities Nevertheless the main properties

depend on both the average composition of the systems and the microstructural distribution of

the comonomer sequences along the macromolecular backbone which is determined by the

reactivity ratios of the macromonomer and the corresponding comonomer in the free radical

polymerization process156 157

In this chapter our work deals with the preparation and characterization of new organo-

soluble associative copolymers based on short hydro-soluble chains of poly (1 3 dioxolane)

(PDXL) Many reports have been published on PDXL macromonomers used to form

hydrogels136 137 158 159 160 161 162 however very few were on graft copolymers with PDXL

branches162 These macromonomers are used for the preparation of amphiphilic graft

copolymers by solution free radical copolymerization with a hydrophobic comonomer

styrene (St) and methyl methacrylate (MMA) Structural characterization of these

copolymers molecular weight determination reactivity ratios and the polymerizability of the

PDXL macromonomer have been discussed Finally their thermal properties are discussed

according to the weight content of PDXL in the copolymers

32 Experimental

156 Eguiburu J L Fernandez-Berridi MJ and San Roman J Polymer 37 (16) (1996) 3615-3622 157 Larraz E Elvira C Gallardo A and San Romaacuten J Polymer 46 (2005) 2040ndash2046 158 Adriaensens P Storme L Carleer R Gelan J and Du Prez F E Macromolecules 35 (2002) 3965-3970 159 Naraghi K Sahli N Belbachir M Franta E and Lutz PJ Polym Inter 51 (2002) 912-922 160 Reguieg F Sahli N Belbachir M and Lutz P J Journal of Applied Polymer Science 99 (2006) 3147-3152 161 Lutz Pierre J Polymer Bulletin (2006) 162 Reibel LC Durand CP and Franta E Can J ChemRev Can Chim 63 (1985) 264-269

bull Ethanol (C2H6O MW 4607 bp 78degC d 081)

Ethanol (Prolabo 95-96) was purified by distillation with 5g of Magnesium and 05g of

iodine for 75ml of alcohol under a N2 atmosphere After discoloration of the mixture

solution a volume of Ethanol was added and then distilled normallyThen it was stored

over molecular sieve

bull 22-azobis(2-methylpropioyonitrile(IUPAC-name)Azobisisobutyronitrile(AIBN)

b) Monomer

bull Styrene (C6H5CH=CH2 MW 10416 bp 145degC d 091)

Styrene (Prolabo product) was purified by distillation over CaHB2 at reduced pressure

bull Methyl Methacrylate (MMA)(H2C=C(CH3)CO2CH3 MW 10012 bp 100degC d

Methyl Methacrylate (Prolabo product) was purified by distillation over CaHB2 at reduced

pressure

322 Synthesis of Poly (Styrene-co-Poly (13-dioxolane))

a) Conventional Free Radical Copolymerization

The reaction route for the conventional copolymerization of Styrene and PDXL

macromonomers using AIBN as the free radical initiator at 60degC is shown in scheme 14

Scheme 14

PDXL macromonomers of different molecular weights were copolymerized with St in THF at

60degC in the presence of 2 2rsquo-azobisisobutyronitrile AIBN (1 based on the total weight of

the monomers) as initiator under a nitrogen atmosphere using different feed molar fractions

of macromonomers The total monomer concentration for was 6 10-1 M in all cases The

copolymerization product is diluted with THF and then added dropwise to a large excess of

ethanol to remove unreacted PDXL macromonomers25 43 and precipitate the copolymers

Then they were finally dried over vacuum at 40degC to constant weight The yields of all

reactions are 70ndash 90 Table 2 indicates the amounts of comonomers initiator and solvent

employed in the copolymerization study

Table 2 Copolymerization of PDXL macromonomers (M1) with Styrene (M2)

Sample M1 M2M1 PDXL (g) (mol)

Styrene (g) (mol)

AIBN (g)

THF (ml)

Conc (moll)

2SP2 FPP2 20 349 174510-4 364 349 10-2 007 60 0610 3SP2 FPP2 30 232 116 10-4 364 349 10-2 006 60 0601 5SP2 FPP2 50 14 69810-4 364 349 10-2 005 60 0593

2SP1 FPP1 20 174 174510-4 364 349 10-2 006 60 0610 5SP1 FPP1 50 07 69810-4 364 349 10-2 005 60 0593 8SP1 FPP1 80 0436 43610-4 364 349 10-2 005 60 0589

b) Controlled Free Radical Copolymerization

The comb-structure copolymer of styrene and PDXL was obtained by grafting-from

mechanism through Nitroxide-Mediated Polymerization

Nitroxide mediated polymerization (NMP) is a controlled radical polymerization (CRP)

technique which already offers the ability to prepare a wide variety of well-defined polymer

architectures119 Despite the significant improvements brought to CRP techniques such as

NMP atom transfer radical polymerization (ATRP) or reversible addition fragmentation chain

transfer (RAFT) the preparation of complex architectures by CRP is restricted by the

exclusion of monomer systems that are polymerized by fundamentally different mechanisms

like lactides ethylenepropylene oxide The most promising approaches to extend the range of

polymer compositions are based on the use of heterofunctional initiators163 allowing the

combination of mechanistically distinct polymerization reactions without the need for

intermediate transformation and protection steps

In the field of NMP the development of multifunctional initiators was focused on TEMPO

and TIPNO which are examples of nitroxides (Scheme 15) It is worth to mention that in

NMP these are used as counter-radicals associated with a conventional azoic initiator so this

pair of initiators is known as a bimolecular system

163 Bernaerts KV Du Prez FE Prog Polym Sci 31 (2006) 671

Scheme 15 TEMPO and based alkoxyamines

Another initiator used for NMP is the commercially available alkoxyamine also called

MAMA-SG1164 (Scheme 16) known as a monomolecular system initiator which is

particularly convenient for functionalization of polymer chain ends164 165 MAMA-SG1 has

been developed by Didier Gigmes and co in collaboration with Arkema Company166 Thanks

to a particularly high dissociation rate constant value kd1 up to now this alkoxyamine has

proved to be one of the most potent alkoxyamines reported in the field of NMP167 168 This

initiator is used for polymerization of styrene and n-butyle acrylate allowing formation of

well-defined linear and star structures

Scheme 16

164 Bruno Grassi Geacuterald Clisson Abdel Khoukh Laurent Billon European Polymer Journal 44 (2008) 50ndash58 165 Jerome Vinas Nelly Chagneux Didier Gigmes Thomas Trimaille Arnaud Favier and Denis Bertin Polymer

49 (2008) 3639-3647 166 Gigmes D Bertin D Guerret O Marque SRA Tordo P Chauvin F et al PCT WO 014926 13 February

2004 167 Chauvin F Dufils PE Gigmes D Guillaneuf Y Marque SRA and Tordo P Macromolecules 39 (2006) 5238 168 Dufils PE Chagneux N Gigmes D Trimaille T Marque SRA and Bertin D Polymer 48 (2007) 5219

Scheme 17 MAMA-SG1 structure and dissociation scheme

bull Multifunctionalization of Polystyrene (HO-PS)

MAMA-SG1 was used to run copolymerization of styrene at 90 mol with HEMA in order

to obtain functionalized polystyrene The monomers and alkoxyamine were introduced in a

250 mL two neck round-bottom flasks fitted with septum condenser and degassed for 15

min by nitrogen bubbling The reaction was performed in bulk at 120 degC under N2 with

vigorous stirring Targeted molecular weight and polydispersity were 30 000 g mol and 12

respectively

After polymerization the final polymer mixture was dissolved in a minimum THF and

precipitated in cold ethanol followed by drying under vacuum at 30degC

bull Synthesis of PS-g-PDXL

PDXL was copolymerized by cationic ring-opening polymerization which was carried out in

40 ml dichloromethane with triflic acid as initiator at room temperature under nitrogen for 24

h in the presence of OH-multifunctionalized PS (1g 3 10-5 mol) as transfer agent 20 ml

(0286 mole) of DXL monomer was added Table 6 gives the molecular characteristics of the

obtained copolymer The amount of the acid used was 20 μl After reaction the resulting

solution is poured into THF Then the product is purified by re-precipitation from THF

solution with a large excess of hexane and the obtained polymer was dried under vacuum at

room temperature The yield was checked by gravimetric determination and found to be about

75 The polymerization route is presented in the scheme below

Scheme 18

323 Synthesis of Poly (Methyl Methacrylate-co-Poly (13-dioxolane))

Same procedure has been used for the synthesis of Poly (Methyl Methacrylate-co-Poly (1 3-

dioxolane)) copolymers The yields of the reactions are in the range of 70ndash 90

Table 3 shows the amounts of comonomers initiator and solvent employed in the

copolymerization reactions

Table 3 Copolymerization of PDXL macromonomers (M1) with MMA (M2)

MMA (g) (mol)

AIBN (g)

THF (ml)

Conc (moll)

2MP2 FPP2 20 374 187 10-4 3744 374 10-2 008 65 0604 3MP2 FPP2 30 2 10 10-4 300 300 10-2 005 50 0620 5MP2 FPP2 50 15 748 10-4 3744 374 10-2 005 60 0636

2MP15 FPP15 20 2 133 10-4 28 280 10-2 005 25 100 3MP15 FPP15 30 187 125 10-4 3744 374 0-2

006 60 0644 5MP15 FPP15 50 112 748 10-4 3744 374 10-2 005 60 0636

2MP1 FPP1 20 2 20 10-4 400 4 10-2

006 50 0840 3MP1 FPP1 50 125 125 10-4 3744 374 10-2 005 64 0604 5MP1 FPP1 80 075 748 10-4 3744 374 10-2 005 60 0636

1H NMR Spectroscopy was used for compositional and structural analysis of the copolymers

1H-NMR spectra of the copolymers were recorded on the high field 400Mhz Advance Bruker

spectrometer All of the 1H NMR samples were dissolved in deuterated chloroform The

integrals of the peaks of copolymer components were used for the calculations to determine

the molecular weights polydispersity indices and the amount of each comonomer that was

incorporated into the copolymer

Size Exclusion Chromatography (SEC) was used in the charaterization of the copolymers to

determine average molecular weights and polydispersity indices SEC Measurements were

performed at 40degC on a Waters 2690 instrument equipped with UV detector (Waters 996

PDA) coupled with a Differential Refractometer (ERC - 7515 A) and four Styragel columns

(106 105 500 and 50degA) THF is employed as the mobile phase with a flow rate of 10

mlmin Polystyrene standard samples were used for calibration

333 Diffraction Scanning Calorimetry

Diffraction Scanning Calorimetry (DSC) measurements are performed on a Modulated

Temperature Differential Scanning Calorimeter Q100 TA instrument under nitrogen at 50

mlmin The samples are hermetically sealed in aluminium pans and they are subjected to a

heating program as follows

For Poly (Styrene-co-Poly (13-dioxolane)) copolymers

- Ramp of 5degCmin to 120degC (Heat flow on conventional DSC)

- Ramp of 2degCmin to -80degC

- Then an isothermal for 5 min

- Modulate +- 060 degC every 60 seconds

- Ramp of 2degCmin to130degC

For Poly (Methyl Methacrylate-co-Poly (13-dioxolane)) copolymers

The thermograms obtained illustrate Glass Transition Temperatures (Tg) and Meltind Points

(Tm) of the copolymers

Methacryloyl-terminated PDXL macromonomers with the Mn range of 1000-2000 gmole

were copolymerized with vinyl and methacrylic monomers in order to obtain amphiphilic

graft copolymers with chemical structure of hydrophobic backbone and hydrophilic side

chains

341 Structural Characterization of the Copolymers

The structure of the copolymers was well defined by 1H-NMR analysis The copolymer 1H-

NMR spectra confirm the formation of copolymers see figures 7 8 and 9 The chemical

shifts of protons of polystyrene and PDXL can be clearly distinguished The following peaks

are assigned for OCHBB2BBO protons at 478 ppm and OCHBB2BBCHBB2BBO protons at 375 ppm (5H CBB6BB

HBB5BB) at 728 711 and 706 ppm as shown in Figure 8 The spectrum of PMMA-PDXL

copolymer is shown in Figure 9 where the chemical shifts of PMMA correspond to the proton

resonance as depicted in the figure the O-CH3 protons are observed at 361 ppm and clear

resonance assigned to the methyl group protons at 085-103 ppm and eventually we observe

the corresponding chemical shifts for OCHBB2BBCHBB2BBO protons (374 ppm) and OCHBB2BBO protons

(477 ppm) to confirm the incorporation of PDXL in the copolymer

Figure 8 1H-NMR spectrum of Styrene-g-PDXL copolymer in CDCl3 (sample 3SP2)

Figure 9 1H-NMR spectrum of MMA-g-PDXL copolymer in CDCl3 (sample 2MP2)

342 Copolymer Molecular Weight and Composition

Copolymerization of PDXL macromonomers with MMA and ST in THF solution was studied

for different molar feed ratio of PDXL The amounts of monomeric units in the copolymers

were determined by elemental analysis The results are presented in Table 4 and 5 which

summarise the characteristics of the graft copolymers in terms of macromonomer feed ratio

(M2M1) and average Mn obtained from SEC as well as copolymer composition in weight and

mole percentages which is determined from 1H-NMR

Table 4 Characteristics of PDXL macromonomers (M1) copolymerized with Styrene (M2)

Sample

M1 in the feed

wt() mol()

M1 in the copolymer

wt() mol()

Mn SEC

2SP2 FPP2 20 49 476 4025 337 9200 162 2 3SP2 FPP2 30 39 322 303 221 8900 162 2 5SP2 FPP2 50 277 196 21 13 7200 159 1

Table 5 Characteristics of PDXL macromonomers (M1) copolymerized with MMA (M2)

Sample

M1 in the feed

wt() mol()

M1 in the copolymer

wt() mol()

Mn SEC

2MP2 FPP2 20 50 476 35 26 21900 198 4 3MP2 FPP2 30 40 322 21 13 25900 157 3 5MP2 FPP2 50 286 196 13 07 87200 455 6 2MP15 FPP15 20 416 45 28 25 19800 193 4 3MP15 FPP15 30 333 322 22 18 15200 277 3 5MP15 FPP15 50 23 196 13 10 24700 16 2 2MP1 FPP1 20 333 476 26 34 21100 319 6 3MP1 FPP1 30 333 322 19 22 17100 197 3 5MP1 FPP1 50 20 196 10 11 13900 354 2

Multifunctionalization of Polystyrene and Synthesis of poly (S-g-PDXL) copolymer give

results which are shown in Table 6 These data have been obtained from the 1H-NMR and

SEC analyses illustrated in figures 10 and 11 The resonance shifts assigned to all components

(PDXL PS and HEMA) are very clear This enables us to make calculations to determine

composition of each copolymer in addition to obtain the average number of grafts and the

number average-molecular weight of a graft

It is observed that the multifunctionalized-PS is composed of 20 in mole of HEMA which

results in 58 grafts (Ng = 58) per molecular chain

After copolymerization multifunctionalized-PS with DXL the copolymer PS-g-PDXL

(DXPS) possesses the following characteristics which are presented in Table 6 It has a

number average-molecular weight of 83000 gmol with 80 of PDXL content The number

average-molecular weight of one graft has been calculated and found to be 1000 gmol

Table 6 Characteristics of functionalized Styrene (HO-PS) and PS-g-PDXL (DXPS)

copolymer

Strusture Sample MnSEC IP PDXL

Ng Graft

32 700

83 000

Figure 10 1H-NMR spectrum of Multifunctionalized of Polystyrene in CDCl3

Figure 11 1H-NMR spectrum of poly (S-g-PDXL) copolymer (DXPS) in CDCl3

341 Determination of Monomer Reactivity Ratios

The application of the classical treatment based on linearization of the copolymerization

equation of Mayo and Lewis91 or the non-linear least-squares approach suggested by Tidwell

and Mortimer95 requires working with high macromonomer concentrations (ie feed

compositions higher than 20-30 of macromonomer)156

The MayondashLewis equation (58) that relates the instantaneous compositions of the monomer

mixture to the copolymer composition is approximated to a simplified form (equation (59))

suggested by Jaacks169 when working with a large excess of one of the comonomers This is

the case of copolymerisation reactions between a conventional comonomer and a

macromonomer of relatively high molecular weight where using low molar concentrations of

macromonomer is mandatory due to its restricted solubility and the extremely viscous media

][ ][ ]

[ ][ ]

[ ] [[ ] [ ]221

MrMMMr

[ ][ ] 1

According to equation (59) the copolymer composition or the frequency of branches is

essentially determined by the monomer composition and the monomer reactivity ratio of the

comonomer r2 (inversely proportional to the macromonomer reactivity) under the limit

condition of [M2][M1] gtgt1 In order to obtain reliable values it is frequently necessary to

run the copolymerisation at different conversions or to carry out several copolymerizations

with different initial monomer ratios170 In such cases an integrated form of equation (59) is

[ ] [ ][ ][ ] 01

2 lnlnMM

rMM tt =

169 Jaacks V Makromol Chem 161 (1972) 161ndash72 170 Larraz E Elvira C Gallardo A and San Romaacuten J Polymer 46 (2005) 2040ndash2046

where [Mi]t[Mi]0 is the ratio among the composition of monomer i at time t and the initial

feed composition A plot of ln ([M2]t[M2]0) versus ln ([M1]t[M1]0) should result in a straight

line with a slope that equals to r2 (the reactivity ratio of the comonomer)

Thus the monomer reactivity ratios between the PDXL macromonomers and the comonomers

were estimated with the data in tables 4 and 5 We can apply equation (60) to the estimation

where M1 and M2 are the PDXL macromonomer and copolymer respectively The monomer

reactivity ratios are determined for macromonomers of different Mn (degree of

polymerization) and summarized in Table 7

Table 7 Monomer reactivity ratios for copolymerization of PDXL macromonomers (M1)

with St and MMA (M2)

Sample M2 M1

macromer Mnth

r2 1r2

SP2 St FPP2 2000 012 plusmn 0006 833

SP15 St FPP15 1500 0042 plusmn 6 10-4 238

SP1 St FPP1 1000 0015 plusmn 3 10-4 6666

MP2 MMA FPP2 2000 002 plusmn 001 50

MP15 MMA FPP15 1500 007 plusmn 0 02 1428

MP1 MMA FPP1 1000 0018 plusmn 001 5555

In the case of copolymerization with Styrene and MMA the results suggest that the reactivity

of the methacrylic double bond in the prepared macromonomers is not affected in their

copolymerization with Styrene or MMA This point is confirmed when analysing the inverse

ratio 1r2 = k21k22 which is sometimes considered as the relative copolymerization reactivity

of a macromonomer171 This quantity is the ratio between the crosspropagation and

homopropagation rate constants of comonomer (2) which is directly proportional to the

reactivity of the macromonomer (1) and gives a clear idea of the relative reactivity of a

growing radical ending in a 2 unit towards the addition of monomer (1) in comparison to the

171 Ito K Progr Polym Sci 23 (4) (1998) 581ndash620

tendency for the homopropagation So we have a situation where r1 gtgt 1 gtgt r2 and it is

expected that the initially formed chains should contain more macromonomers and then more

comonomer segments are added These are only assumptions but they give an indication

about the probable composition drift of the graft copolymers obtained On the other hand in

the case of copolymerization of poly (13dioxolane) macromonomers with styrene (Figure

12) the results show that r2 increases with increasing PDXL side chain length (in terms of

average Mn) and this leads to say that the side macromonomer chain length affect the

reactivity of the comonomer Thus this indicates that a growing radical of macromonomer

with a shorter chain length (ie lower Mn ) attacks more frequently a monomer of the same

nature than it does a macromonomer with a longer length (ie higher Mn) as it can be noticed

from the results in Table 7

However the r2 values of the copolymerization with MMA as shown in Figure 13 give

unclear dependence on the side poly (13dioxolane) macromonomer chain length this may be

due to the resulting polydispersity of the copolymerization Mentioned behaviour may be

related with the reactive structure of comonomers vinyl in the case of Styrene or methacrylic

in the case of MMA in regard to the ending methacrylic double bond of macromonomers

besides the hydrophilic character of the macromonomers

2] t[M

ln[M1]tln[M1]0

r2 = 0015 plusmn 3 10-4 SP1

r2 = 0042 plusmn 6 10-4

2] t[M

ln[M1]tln[M1]0

r2= 012 plusmn 0006

2] t[M

ln[M1]tln[M1]0

Figure 12 Application of Jaacksrsquo treatment to the St-g-PDXL copolymerization systems

(a) SP1 (b) SP15 (c) SP2

2] t[M

ln[M1]tln[M1]0

r2 = 0018 plusmn 001 MP1

2] t[M

ln[M1]tln[M1]0

r2 = 007 plusmn 002MP15

036788

2] t[M

ln[M1]tln[M1]0

r2 = 002 plusmn 001 MP2

Figure 13 Application of Jaacksrsquo treatment to the MMA-PDXL copolymerization systems

(a) MP1 (b) MP15 (c) MP2

341 Glass Transition Temperatures

Thermal analysis of Styrene-g-PDXL copolymers allows to determine their glass transition

and melting temperatures In the first place the measurements were performed on a

conventional DSC from which the thermograms obtained show an overlapping of PS glass

temperature and PDXL melting point signals This has been observed for all samples A

different approach in the characterisation of these copolymers was by means of Modulated

Temperature Differential Scanning Calorimeter (MTDSC) which is an extension of

conventional DSC This approach combines high resolution with high sensitivity by use of a

sinusoidal temperature modulation superimposed on a constant temperature or linear

temperature program with a small underlying average heating rate172 173 In comparison to

conventional DSC the MTDSC analysis enables the simultaneous calculations of an

additional quantity the cyclic or modulus of heat capacity Cp (J g-1K-1 172)

is the amplitude of the cyclic heat flow (Wg-1) and AWhere AHF Tω is the amplitude of cyclic

heating rate with AT the temperature modulation amplitude (K) ω the modulation angular

frequency (2πp) and p is the modulation period (s)172

In fact the MTDSC splits the overlapped signals into two distinct temperatures melting

temperature of the hydrophilic grafts and glass transition temperature of the hydrophobic

backbone as can be noticed in Figure 14 in which melting temperature appears to be 5626degC

which is closer to the glass transition temperature with a value of 5671degC From the results

obtained out of the thermogram it is clear that the measurements show very close values of

Tm and Tg for all copolymer samples where in conventional DSC these two temperatures

cannot be distinguished

172 Dreezen G Groeninckx G Swier S and Van Mele B Polymer 42 (2001) 1449-1459 173 Reading M Elliot D and Hill VL J Thermal Anal 40 (1993) 949-955

Figure 14 MTDSC thermogram of 5SP1 copolymer at heating rate of 2degCmin

Tg was taken at the midpoint of the transition region The results obtained are shown in

Tables 8 and 9 for copolymers with Styrene and MMA respectively Then a plot of the

copolymers Tg has been constructed against PDXL content in order to determine the effect of

the latter on Tgrsquos As it can be noticed in the Figure 15 Tg of the copolymers decreases

exponentially with increasing PDXL content and this may be due to the decrease in the

intermolecular interactions between the molecular chains and can be associated with higher

mobility and flexibility of the polymeric chains when PDXL is incorporated in the

copolymers The results clearly indicate that Tg values of the copolymers depend on the

composition of comonomers and a decrease with increasing PDXL content in the obtained

copolymers

Table 8Transition temperatures of Styrene-g-PDXL copolymers obtained by thermal

analysis (DSC) Sample PDXL content Tg wt () (degC) 8SP 85 7489 1

5SP 1424 5671 1

5SP 152 5590 15

21 6739 5SP 2

303 4480 3SP 2

34 2665 2SP15

4025 2SP 4060 2

Table 9Transition temperatures of MMA-g-PDXL copolymers obtained by thermal analysis

Sample PDXL content Tg

wt () (degC)

5MP 10 10545 1

5MP 13 8278 15

21 6576 3MP 2

22 7550 3MP 15

26 7013 2MP1

5 10 15 20 25 30 35 40 4520

SP COPOLYMERSTg

(degC)

PDXL content in wt()

10 15 20 2560

Tg (deg

MP COPOLYMERS

Figure 15 Glass transition temperatures vs PDXL macromonomer content for copolymer

systems (a) Styrene-g-PDXL copolymers (b) MMA-g-PDXL copolymers

Conclusion

Methacrylate-terminated PDXL macromonomers were copolymerized with St and MMA

using different feed molar ratios Both feed molar ratio and the size of the graft influence the

composition of the copolymers The macromonomer reactivity estimation suggests that the

length of the PDXL side chains does affect the reactivity of the methacrylic double bond of

the macromonomer when copolymerized with St However in the case of copolymerization

with MMA there is no dependence on the graft size Finally from DSC measurements the

values of Tg depend on the composition and the size of the PDXL grafts In all copolymers

the increase in amount of the incorporated PDXL macromonomer results in a substantial

decease in glass transition

References 152 Fernandez-Garcia M Luis de la Fuente J Cerrada ML and Madruga EL Polymer 43 (2002) 3173-3179 153 Hou SS and Kuo PL Polymer 42 (2001) 2387-2394 154 Roos SG Muller Axel H E and K Matyjaszewski Macromolecules 32 (1999) 8331-8335 155 Meijs F and Rizzardo E JMacromol Sci Rev Macromol ChemPhys 33 (C30) (1990) 305 156 Eguiburu J L Fernandez-Berridi MJ and San Roman J Polymer 37 (16) (1996) 3615-3622 157 Larraz E Elvira C Gallardo A and San Romaacuten J Polymer 46 (2005) 2040ndash2046 158 Adriaensens P Storme L Carleer R Gelan J and Du Prez F E Macromolecules 35 (2002) 3965-3970 159 Naraghi K Sahli N Belbachir M Franta E and Lutz PJ Polym Inter 51 (2002) 912-922 160 Reguieg F Sahli N Belbachir M and Lutz P J Journal of Applied Polymer Science 99 (2006) 3147-3152 161 Lutz Pierre J Polymer Bulletin (2006) 162 Reibel LC Durand CP and Franta E Can J ChemRev Can Chim 63 (1985) 264-269 163 Bernaerts KV Du Prez FE Prog Polym Sci 31 (2006) 671 164 Bruno Grassi Geacuterald Clisson Abdel Khoukh Laurent Billon European Polymer Journal 44 (2008) 50ndash58 165 Jerome Vinas Nelly Chagneux Didier Gigmes Thomas Trimaille Arnaud Favier and Denis Bertin Polymer

2004 167 Chauvin F Dufils PE Gigmes D Guillaneuf Y Marque SRA and Tordo P Macromolecules 39 (2006)

5238 168 Dufils PE Chagneux N Gigmes D Trimaille T Marque SRA and Bertin D Polymer 48 (2007) 5219 169 Jaacks V Makromol Chem 161 (1972) 161ndash72 170 Larraz E Elvira C Gallardo A and San Romaacuten J Polymer 46 (2005) 2040ndash2046 171 Ito K Progr Polym Sci 23 (4) (1998) 581ndash620 172 Dreezen G Groeninckx G Swier S and Van Mele B Polymer 42 (2001) 1449-1459 173 Reading M Elliot D and Hill VL J Thermal Anal 40 (1993) 949-955

CHAPTER IV Compatibilization Effect of Poly (Styrene-g-Poly

(1 3 Dioxolane)) on Immiscible Polymer Blends

of Polystyrene and Poly (Ethylene Glycol)

41 Background

411 Physical Blends

Physical blending is defined as the simple mechanical mixing of two or more polymers either

in the melt or in solution174 At first glance this approach would seem to be ideal for

preparing hybrids as blending is considered a simple and economical procedure that is

commonly used to produce new products from existing materials175 However in polymer

science the effectiveness of blending is dependent upon the degree of compatibility of the

polymers involved176 At least three general types of materials can result from blending

depending on the mutual solubility and semi-crystallinity of the constituents

412 Equilibrium Phase Behavior

Mixing of two amorphous polymers can produce either a homogeneous mixture at the

molecular level or a heterogeneous phase-separated blend Demixing of polymer chains

produces two totally separated phases and hence leads to macrophase separation in polymer

blends Some specific types of organized structures may be formed in block copolymers due

to microphase separation of block chains within one block copolymer molecule

Two terms for blends are commonly used in literature miscible blend and compatible blend

The terminology recommended by Utracki177 will be used By the miscible polymer blend it

means a blend of two or more amorphous polymers homogeneous down to the molecular

174 Paul D R and Newman S Eds ldquoPolymer Blendsrdquo Academic Press New York Vol I-II (1979) 175 Noshay A and McGrath J E ldquoBlock Copolymers-Overview and Surveyrdquo Academic Press New York (1977) 176 Olabisi O Robeson L M and Shaw M ldquoPolymer-Polymer Miscibilityrdquo Academic Press New York (1979) 177 L A Utracki ldquoPolymer Alloys and Blends Thermodynamic and Rheologyrdquo Hanser Publishers Munich (1989)

level and fulfilling the thermodynamic conditions for a miscible multicomponent system An

immiscible polymer blend is the blend that does not comply with the thermodynamic

conditions of phase stability The term compatible polymer blend indicates a commercially

attractive polymer mixture that is visibly homogeneous frequently with improved physical

properties compared with the constituent polymers

Miscible blends occur spontaneously when the overall energy of mixing (ΔGmix) is negative

as defined by the Gibbs-Helmholtz free energy equation (Equation 62)

In the Gibbs-Helmholtz equation ΔHmix is the enthalpy of mixing and ΔSmix is the entropy of

mixing while T is the temperature of the blend Flory-Huggins178 and Scott179 have made

further correlation of enthalpy and entropy as a function of the polymer components and their

properties (Equation 63)

In Equation 63 χ is a measure of the polymer-polymer interaction energy V is the volume of

the system Φi is the volume fraction of polymer i R is the gas constant T is the temperature

of blending Vr is the reference volume of the monomers and χi is the degree of

polymerization

Examination of Equation 63 reveals that the entropy of mixing is highly dependent on the

molecular weight of the blended polymers while the enthalpy is much more dependent on the

level of interaction between the polymer types Additionally Scott showed that as molecular

weight increases to the level commonly found in commercially useful materials ΔS

approached zero (0) Therefore polymer blends of commercial importance are primarily

influenced by the rate of enthalpy However for polymers with weak interactions (as χ

approaches 1) eg as observed in most polymer pairs the enthalpy of mixing can be further

reduced according to Equation 64

178 Flory P J Principles of Polymer Chemistry Cornell Ithaca NY (1953) 179 Scott R L J Chem Phys 17 (1949) 279

In Equation 64 δi is the polymerrsquos solubility parameter (an estimation of its ability to be

dissolved in a range of solvents) derived from the square root of the cohesive energy density

pioneered by Hildebrand180 Thus most early work with polymer blends concentrated on

matching the solubility parameters of the component polymers

Unfortunately the theoretical maximum difference in solubility for a 5050 polymer blend is

only 01 (calcm3)12 This narrow margin is much smaller than the standard error among

methods used to determine solubility parameters181 The ability to predict miscibility of

polymer pairs with strong interactions such as donor-acceptor and hydrogen bonding which

can increase miscibility by creating an exothermic reaction upon mixing (ΔH lt0) have been

attempted for many years with varying degrees of success

The formation of miscible blends is dependent on several factors including molecular

structure average chain length tacticity of the polymers as well as the temperature of mixing

and the blending method If the blended polymers are miscible (ΔGmix lt 0) and thus

compatible the resulting material will display an amalgamation of properties which are

predictable using the same techniques as those used for random or statistical copolymers

Polymer blends account for a significant percentage of polymer production and are produced

either to reduce costs to aid in processing or to improve a variety of specific properties For

example polycarbonates have been blended with polybutylene terephthalates to increase

chemical resistance and to aid in processing while polyphenylene oxides are bended with

polystyrenes to improve toughness and increase glass transition temperatures182

413 Compatibilization

As it follows from thermodynamics the blends of immiscible polymers obtained by simple

mixing show a strong separation tendency leading to a coarse structure and low interfacial

180 Hildebrand J H and Scott R L ldquoThe Solubility of Non-electrolytesrdquo 3rd ed Reinhold Publishing Corp

New York (1950) 181 Paul D R and Barlow J W ldquoIn Multiphase Polymersrdquo Advances in Chemistry Series no176 Cooper S

L Estes G 182 Paul D R Bucknall C B ldquoPolymer Blendsrdquo Wiley New York (1999)

adhesion The final material then shows poor mechanical properties On the other hand the

immiscibility or limited miscibility of polymers enables formation of wide range structures

some of which if stabilized can impart excellent end-use properties to the final material To

obtain such a stabilized structure it is necessary to ensure proper phase dispersion by

decreasing interfacial tension to suppress phase separation and improve adhesion This can be

achieved by modification of the interface by the formation of bonds (physical or chemical)

between the polymers This procedure is known as compatibilization and the active

component creating the bonding as the compatibilizer174 177 183

The most popular method of compatibilization is by addition of a third component In most

cases such an additive is either a block or graft copolymer Since the key requirement is

miscibility it is not necessary for the copolymer to have identical chain segments as those of

the main polymers It suffices that the copolymer has segments having specific interactions

with the main polymeric components viz hydrogen bonding dipole-dipole dipole-ionic

Lewis acid-base etc

Addition of a block or graft copolymer reduces the interfacial tension and alters the molecular

structure at the interface Thus compatibilization by addition changes not only the interfacial

properties but it may affect the flow behavior (hence processability)

One of the disadvantages of the addition method is the tendency of the added copolymers to

form micelles These reduce the efficiency of the compatibilizer increase the blend viscosity

and may lessen the mechanical performance

414 Incorporation of Copolymers for Compatibilization

Block or graft copolymers with segments that are miscible with their respective polymer

components show a tendency to be localized at the interface between immiscible blend

phases Random copolymers sometimes also used as compatibilizers reduce interfacial

tension but their ability to stabilize the phase structure is limited184 Finer morphology and

higher adhesion of the blend lead to improved mechanical properties The morphology of the

resulting two-phase (multiphase) material and consequently its properties depend on a

number of factors such as copolymer architecture (type and molecular parameters of

segments) blend composition blending conditions

183 D R Paul J W Barlow and H Keskula in J I Kroschwitz ed-in-ch ldquoEncyclopedia of Polymer Science

and Engineeringrdquo 2nd ed Wiley-Interscience New York (1985) 184 G P Hellmann and M Dietz Macromol Symp 170 (2001)

In Scheme19 the conformation of different block graft or random copolymers at the

interface is schematically drawn

Scheme 19 Possible localization of A-B copolymer at the AB interface Schematic of

connecting chains at an interface a-diblock copolymers b-end-grafted chains c-triblock

copolymersdmultiply grafted chain and e-random copolymer

415 The Effect of Compatibilizer on a Blend

The presence of a compatibilizer at the interface substantially affects the development of the

phase structure of molten blends in the flow and quiescent state The position and width of the

concentration region related to co-continuous morphology are affected by two competing

mechanisms A decrease in interfacial tension caused by a compatibilizer favors the formation

and stability of co-continuous structures

The effect of a compatibilizer on fineness of the phase structure can be understood through its

effects on droplet breakup and coalescence A decrease in interfacial tension due to the

presence of a compatibilizer decreases the droplet radius R

Effect of the Compatibilizer Architecture

Compatibilization efficiency of various copolymers follows from their thermodynamic and

microrheological effects It has been generally accepted that the total molecular weight of the

copolymer molecular weight of its blocks and their number are the main structural

compatibilizer characteristics affecting the phase structure of the final blend

Effect of Compatibilizer Concentration

The compatibilizing efficiency of the copolymers is besides the architecture a function of

their concentration The effect of a compatibilizer concentration has been quantitatively

characterized by the emulsification curvemdashthe dependence of the average particle diameter of

the minor dispersed phase on copolymer concentration185 The particle diameter decreases

with increase of copolymer concentration until a constant value is obtained For most systems

this value is achieved if the copolymer amount is 15ndash25 of the dispersed phase

416 Methods of Blend Preparation

Five different methods are used for the preparation of polymer blends186 187 melt mixing

solution blending latex mixing partial block or graft copolymerization and preparation of

interpenetrating polymer networks It should be mentioned that due to high viscosity of

polymer melts one of these methods is required for size reduction of the components (to the

order of μm) even for miscible blends

bull Melt mixing is the most widespread method of polymer blend preparation in practice

The blend components are mixed in the molten state in extruders or batch mixers Advantages

of the method are well-defined components and universality of mixing devicesmdashthe same

extruders or batch mixers can be used for a wide range of polymer blends Disadvantages of

the method are high energy consumption and possible unfavorable chemical changes of blend

components This procedure has not been used so far in industrial practice because of large

energy consumption

bull Solution blending is frequently used for preparation of polymer blends on a laboratory

scale The blend components are dissolved in a common solvent and intensively stirred The

blend is separated by precipitation or evaporation of the solvent The phase structure formed

in the process is a function of blend composition interaction parameters of the blend

components type of the solvent and history of its separation Advantages of the process are

rapid mixing of the system without large energy consumption and the potential to avoid

185 BD Favis in D R Paul and C B Bucknall eds Polymer Blends Vol 1 Formulations John Wiley amp Sons Inc New York Chap 16 (2000) 186 60 B D Gesner ldquoEncyclopedia of Polymer Science and Technologyrdquo Interscience New York Vol 10

(1969) 694ndash709 187 R D Deanin in H F Mark N G Gaylord and N M Bikales eds ldquoEncyclopedia of Polymer Science and Technologyrdquo Suppl Wiley-Interscience New York Vol 2 (1977) 458

unfavorable chemical reactions On the other hand the method is limited by the necessity to

find a common solvent for the blend components and in particular to remove huge amounts

of organic (frequently toxic) solvent Therefore in industry the method is used only for

preparation of thin membranes surface layers and paints

bull A blend with heterogeneities on the order of 10 μm can be prepared by mixing of

latexes without using organic solvents or large energy consumption Significant energy is

needed only for removing water and eventually achievement of finer dispersion by melt

mixing The whole energetic balance of the process is usually better than that for melt mixing

The necessity to have all components in latex form limits the use of the process Because this

is not the case for most synthetic polymers the application of the process in industrial practice

is limited

bull In partial block or graft copolymerization homopolymers are the primary product

But an amount of a copolymer sufficient for achieving good adhesion between immiscible

phases is formed188 In most cases materials with better properties are prepared by this

procedure than those formed by pure melt mixing of the corresponding homopolymers The

disadvantage of this process is the complicated and expensive start-up of the production in

comparison with other methods eg melt mixing

bull Another procedure for synthesis of polymer blends is by formation of interpenetrating

polymer networks A network of one polymer is swollen with the other monomer or

prepolymer after that the monomer or prepolymer is crosslinked189 In contrast to the

preceding methods used for thermoplastics and uncrosslinked elastomers blends of

reactoplastics are prepared by this method

188 J Schies and D B Priddy eds ldquoModern Styrenic Polymers Polystyrene and Styrenic Copolymersrdquo John

Wiley amp Sons Chichester UK (2003) 189 L H Sperling ldquoInterpenetrating Polymer Networks and Related Materialsrdquo Plenum Press New York

(1981)

42 Experimental

421 Materials

Polymers used in this research were PEG and PS PEG was purchased from MERCK

company General Purpose PS was obtained from ENPC TP1-Chlef Company Physical and

Structural characterizations of these materials were performed by SEC 1H-NMR and DSC

422 Blend Preparation

PSPEG blends of 5050 wt were prepared by solution casting from THF 40degC The

polymer solutions were stirred until complete miscibility and then cast onto glass dishes and

left to evaporate the solvent to the atmosphere To remove residual solvent after casting the

blends were dried in vacuum oven at 40degC for a weak Table 10 shows the quantities of the

copolymers used for compatibilization of the blends of PSPEG

Table 10 The quantities of the copolymers used for compatibilization of the blends of

Weight of the dispersed phase

10 20 30 40

Weight of the total weight of the blend

47 9 13 166

43 Characterization Techniques for Compatibilization

431 Dilute Solution Viscometric Measurements

Viscometric measurements were performed at 30 plusmn 002 degC using the Ubbelohde capillary

viscometer (Schott Gerte KPG-type) having a viscometer constant K = 003 It was

immersed in a constant temperature bath The samples were dissolved in THF filtered and

then added to the viscometer reservoir Dilutions were carried out progressively by adding

fresh solvent to the viscometer starting from 1gdl and allowing 10 min for the solution to

reach thermal equilibrium Six dilutions were made for each blend sample At least five

observations were made for each measurement

Relative viscosities of polymer solutions were calculated by dividing the flow times of

solutions by that of the pure solvent The data were plotted using the Huggins equation with

the intrinsic viscosity [η] (dlg-1) determined by extrapolation to infinite dilution

432 Optical Microscopy

The samples were observed under a binocular lens optical microscope MOTIC coupled with computer-controlled CCD camera

433 FTIR Analysis

FTIR measurements were performed on a Bruker IFS 66S Fourier transform spectrometer at

room temperature The recorded wave number was in the range of 4000-400 cm-1 The spectra

were obtained at a resolution of 2 cm-1 and of 100 scans Samples for FTIR spectroscopic

characterization were prepared by grinding the blends with KBr (5 w ) and compressing the

mixtures to form sheets

44 Results and Discussion Polyethylene glycol (PEG) is very interesting and important polymers PEG presents good

properties eg hydrophilicity solubility in water and in organic solvents nontoxicity and

absence of antigenicity and immunogenicity190It has attracted increasing attention due to its

potential applications as biomedical and environment friendly materials PEG has been

widely used as a modifier for biomedical surfaces to reduce the protein absorption and

improve their biocompatibility192 and as a stabilizer for emulsion and dispersion It has also

been used as a plasticizer for poly (lactide) (PLA) which is stiff and brittle as a

biodegradable packaging material193

On the other hand polystyrene shows excellent processability good appearance tensile

strength and thermal and electrical characteristics however its brittleness considerably limits

its use in high performance products

Both PS and PEG are widely used commodity polymers Detailed studies on their miscibility

may contribute to technological and environmental applications These polymers form an

interesting pair to study since they exhibit contrasting physical properties PS is a

190 Herold CB Keil K Bruns DE Biochem Pharmacol 38 (1989) 73 192 CChorng-Shyan Cheng-kang Lee and Kuan-chaung Lin Journal of Polymer Research 13 (2006) 247-254 193 Y Hua YS Hua V Topolkaraevb A Hiltnera E Baera Polymer 44 (2003) 5681ndash5689

hydrophobic polymer whereas PEG is hydrophilic PEG is a much softer material than PS

PSPEO blends have been reported as incompatible materials in the literature194 195

N Watanabe et al have reported compatibilization effect of poly (styrene-co-methacrylic

acid) on immiscible blends of this system196

441 Characterization of the Blend Components

Analysis by SEC provides number average-molecular weights and polydispersity indices of

all materials DSC measurements performed to determine their glass transition temperatures

as well as melting point and degree of crystallinity of PEG (See Figure16) 1HNMR spectroscopy analysis was performed on these polymers to determine essentially the

tacticity of PS and also to get information about end groups of PEG which was found to

possess an OH group at each end It has been also determined that the stereoregularity of PS

is Syndiotactic-Atactic (rather highly syndiotactic) (See Figures 17)

Physical characteristics of materials used are given in Table11

Table 11 Characteristics of PEG PS and PMMA used in this research

Materials

Source Specific gravity

Mw gmol

degC Tm range

degC Crystallinity

PS ENPC TP1-Chlef (from CHI MEI Corp)

128 000

PEG Merck

35 000

60 ndash 65

194 S P Timg B J Bulkin and E M Pearce J Polym Ser Polym Chem 19 (1981) 451 195 T Suzuki Y Murakami T lnm and Y Takenam] Poljmer J 13 1027 (1981) 196 Norimasa Watanabe Isamu Akiba and Saburo Akiyama Europ Polymer Journal 37 (2001) 1837-1842

Figure 16 1H-NMR spectrum of PEG (Merck) in CDCl3

Figure 17 1H-NMR spectrum of Commercial Styrene (ENPC TP1-Chlef) in CDCl3

442 Study of Compatibilization by Dilute Solution Viscometry

a) Introduction

Polymer blends are physical mixtures of structurally different polymers which interact

through secondary forces with no covalent bonding Blending of the polymers may result in a

reduction in the basic cost and improved processing and also may enable properties of

importance to be maximized The polymer blends often exhibit properties that are superior

compared to the properties of each individual component polymer197 198 199 200 The main

advantages of the blend systems are simplicity of preparation and ease of control of physical

properties by compositional change201 202 However the mechanical thermal rheological and

197 HJ Rhoo HT Kim JK Park TS Hwang Electrochim Acta 42 (1997) 1571 198 B Oh YR Kim Solid State Ionics 124 (1ndash2) (1999) 83 199 K Pielichowski Eur Polym J 35 (1999) 27 200 AM Stephen TP Kumar NG Renganathan S Pitchumani R Thirunakaran and N Muniyandi J Power

Sources 89 (2000)80 201 JL Acosta E Morales Solid State Ionics 85 (1996) 85

other properties of a polymer blend depend strongly on its state of miscibility on the

molecular scale203

There have been numerous techniques of studying the miscibility of the polymeric blend The

most useful techniques are dynamic mechanical thermal electron-microscopic IR

spectroscopic refractive index203 optical microsscopic204 and viscometric techniques 179 205

Because of its simplicity viscometry is an attractive and very useful method for studying the

compatibility of polymer blends Additional advantages ie that no sophisticated equipment

is necessary and that the crystallinity or the morphological states of the polymer blends do

affect the result206 make the viscometric method more convincing for characterizing polymer

mixtures The principle of using a dilute solution viscosimetry to measure the miscibility is

based on the fact that while in solution molecules of both component polymers may exist in

a molecularly dispersed state and undergo a mutual attraction or repulsion which will

influence the viscosity It is assumed that polymerndashpolymer interaction usually dominate over

polymerndashsolvent ones207 The presence of interactions between atoms or groups of atoms of

unlike polymers is essential to obtain a miscible polymer blend177 179

Estimation of the compatibility of different pairs of polymers based on dilute solution

viscosity for a ternary polymerpolymer-solvent system has been attempted by several

authors including Mikhailov and Zeilkman208 Bohmer and Florian209 Feldman and Rusu210

Krigbaum and Wall211 and Catsiff and Hewett212

The compatibilization of the blends in question has been characterized by viscosity technique

using the Krigbaum and Wall interaction parameter Δb The versatility of the viscometric

technique is not affected by the choice of the solvent as was shown by Kulshreshta et al213

In this section we discuss in details our investigation on the compatibilization of the two

polymer blend systems PSPEG and PMMAPEG 202 AM Rocco RP Pereira MI Felisberti Polymer 42 (2001)5199 203 AV Rajulu RL Reddy SM Raghavendra and SA Ahmed Eur Polym J 35 (6) (1999) 1183 204 W Wu X Luo D Ma Eur Polym J 35 (1999) 985 205 Krause S ldquoPolymer-polymer compatibilityrdquo in PolymerBlends Vol 1 ed D R Paul and S Newman

Academic Press NY (1978) 206 Kulshreshta AK Singh B P and Sharma Y N Eur Polym J 24 (1988) 29 207 Z Pingping Y Haiyang Z Yiming Eur Polym J 35 (1999) 915 208 Mikhailov NV and Zeilkman SG Kolloid Z 19 (1957) 465 209 Bohmer B Berek D and Florian S Eur Polym J 6 (1970) 471 210 Feldman D and Rusu M EurPolym J 6 (1970) 627 211 Krigbaum W R and Wall F J Journal of Polym Sci 5 (1950) 505 212 Catsiff E H and Hewett W A J Appl Polym Sci 6 (1962) 530 213 Kulshreshta AK Singh B P and Sharma Y N Eur Polym J 2 (1988) 191

b) Theoretical background

The main aspects of the application of dilute solution viscometry method for the study of

interactions and miscibility phenomena in dilute multicomponent polymer solutions were

described Only the most important features will be repeated here It is common to use

empirical relations such as Hugginsrsquo equation214

for the description of the concentration dependence of viscosity of polymer solutions This

relation is strictly valid only for binary polymer solutions However equations like that of

Krigbaum and Wall211

And of Catsiff and Hewett212

were proposed for ideal ternary polymer solutions of the polymer 1+ polymer 2+ solvent type

In previous relations ηsp denotes the specific viscosity [η] is the intrinsic viscosity (limiting

viscosity number) c stands for the mass concentration of polymer and kH is Hugginsrsquo

constant which may be related (in an empirical manner) to the thermodynamic quality of

solvent Relative mass fractions of dissolved polymers wi are used to describe the

composition dependence of viscosity in ternary systems Quantities b 12 and b12 are used to

define the ideal behavior of ternary polymer solutions These are calculated by

214 ML Huggins J Am Chem Soc 64 (1942) 116

respectively Here b denotes the slope of Hugginsrsquo equation for binary solutions

Moreover it has been shown215 that both the sign and the extent of the deviation of

experimental from theoretical b-values may be correlated to the interactions between

polymeric components of a system under consideration The quantities of interest (miscibility

criterion variables) are defined by

or can be written in another form

where m denotes the polymer mixtures Δb intermolecular interaction parameter between

polymer 1and 2 and is considered a good criterion to predict the polymer-polymer

compatibility209 216 217 Δb 0 indicates that the two polymers are compatible whereas

Δb0 indicates that they are incompatible

c) Discussion of the Results

Herein we discuss in detail the compatibilization of PSPEG blends with the synthesized graft

copolymers by viscometric technique The plot of reduced specific viscosity of polymers

versus total polymeric concentration yields a straight line and the intercept and slope

correspond to intrinsic viscosity [η] and molecular interaction coefficient b respectively The

viscosity data for the homopolymers and their blends are presented in Tables 12 and 13

Table 12 Interaction coefficient for binary solutions (polymersolvent) 215 E Schroder G Muller and KF Arndt ldquoLeitfaden der PolymerCharakterisierungrdquo Akademie Verlag Berlin (1982) 216 Garcia R Melad O Gomez C M Figueruelo J E and Campos A Eur Polym J 35 (1999) 4 217 Melad O Asian J of Chem 14 (2002) 849

Polymer components PEG PS

b11 007327 minus

b22 minus 02117

b12 = (b11 b22)12 = 01245 (theo)

Table 13 Interactions parameters for PSPEG blends with poly (St-g-PDXL) copolymers

(2SP2 2SP1 and DXSP) as compatibilizers

Copolymers (b12) and (Δb) Amount of incorporated copolymer in weight percent

0 10 20 30 40

DXSP b12 003511 01295 01680 01833 01947

Δb - 00894 00050 00435 00588 00702

2SP2 b12 003511 009826 01052 01314 01515

Δb - 00894 - 00262 - 00193 00069 00270

2SP1 b12 003511 minus minus minus 01262

Δb - 00894 minus minus minus 00017

For incompatible blends the incompatible molecules refuse to overlap thus they shrink in

size which leads to a decrease in hydrodynamic volumes As a matter of fact the crossover in

the reduced viscosity-concentration plot is observed

As far as we are concerned with the blend of PSPEG the results obtained present similar

situation Figure 18 shows the Huggins plots for the homopolymers and the (5050) blend of

PSPEG In this figure a crossover is observed and a decrease of slope occurs at about 05

gdl in the viscosity-concentration plot Above this concentration two incompatible polymers

PS and PEG undergo mutual repulsion in dilute solution the hydrodynamic volume of chains

is lower The reduction of the hydrodynamic volume will result in a decrease of the reduced

viscosity of solution correspondingly the slope of the plot suddenly declines

02 03 04 05 06 07 08 09 10 11

08PS PEG and PSPEG (5050)

PS PSPEG 0 PEG

C (dll)

Figure 18 Plots of reduced viscosity (ηspc) vs concentration for PS PEG and PSPEG

blend (0) in THF at 30degC

Figures 19 20 21 and 22 show the incorporation of various amounts of copolymers in the

immiscible blend As far as the amount of the compatibilizers increases the crossover of the

plots occurs at very low concentration or even it is not observed In addition the slope of the

plot increases with an increase of the amount of the compatibilizers introduced in the blend

This is due to the mutual attraction of the blend components which is enhanced by the

presence of the copolymers As a matter of fact the latter act as compatibilizing agents

allowing to the blends to exhibit miscibility

02 03 04 05 06 07 08 09 10 1101

07BLENDS WITH DXPS

PSPEG 0 10 20 30 40 Re

ity η

C (gdl)

Figure 19 Plots of reduced viscosity (ηspc) vs concentration for PSPEG blends in THF at

30degC with various amounts of DXPS copolymer

02 03 04 05 06 07 08 09 10 1101

08BLENDS WITH 2SP2

PSPEG 0 10 20 30 40 Re

ity η sp

C (gdl)

30degC with various amounts of 2SP2 copolymer

02 03 04 05 06 07 08 09 10 1101

08BLEND WITH 2SP1 40

PSPEG 0 2SP1 40 Re

ity η sp

C (gdl)

30degC with 40 of the dispersed phase of 2SP1 copolymer

02 03 04 05 06 07 08 09 10 1100

DXPS 40 2SP2 40

2SP1 40

2SP1 40 2SP2 40 DXPS 40 Re

ity η

C (gdl)

Figure 22 comparison of plots of reduced viscosity (ηspc) vs concentration for PSPEG

blends in THF at 30degC with 40 of the dispersed phase of DXPS 2SPS2 and 2SP1

copolymer

Figure 22 compares the three copolymers used for compatibilization of PSPEG with respect

to 40 by weight of the dispersed phase addition to the blends

Krigbaum and Wall suggested that information about the interaction between two polymers

should be obtained from the difference of experimental b12 and theoretical b12 Δb A positive

difference between the experimental and theoretical interaction coefficients is evidence of a

compatible polymer pair The higher the value of Δb the higher the extent of compatibility

Negative values refer to repulsive interaction and incompatible mixes The values of Δb

according to equation 73 for different blends with compatibilizers are given in Table 13 and

Figure 23

0 10 20 30 40 5

PS PEG BLENDS

2SP2 DXPS

Amount of incorporated copolymer w ()

Figure 23 Dependence of viscometric interaction parameter (Δb) on the amount of

copolymers (DXPS and 2SP2) used for compatibilization

It was observed as the amount of compatibilizers increases values of the interaction

parameter increase thereby increasing the compatibility between the two polymer

components of the blend Consequently this indicates that these copolymers act as

compatibilizing agents in the immiscible blends of PS and PEG Now in comparing these

copolymers in terms of structure (number of grafts) and PDXL content it can be noticed that

the results obtained DXPS ( 71 w of PDXL) copolymer show higher values of Δb than

2SP1(30 w of PDXL) and 2SPS2 (4025 w of PDXL) do This is due to the comb-

structure of the DXPS copolymer (synthesized by CRP) and therefore containing more grafts

(Ng = 58) than the other copolymers Besides the amount of PDXL in the copolymer PDXL

includes polar groups which provide associative interactions with one of the blend

components (PEG) and thus undergoes significant effects upon compatibilization In the

figure below it can be seen that addition of 10 by weight of the dispersed phase (47 of

total weight of the blend) of DXPS is sufficient to compatibilize the immiscible blend of

PSPEG (5050) Then a drastic increase of the interaction parameter with the addition of the

compatibilizer (DXPS) compared to the addition of either 2SP2 or 2SP1 (Table 13)

From the results shown in the graph miscibility of the blend can be achieved by incorporating

around 25 (11 of total weight of the blend) of 2SP2 copolymer However compatibibility

of the blend with 2SP1 copolymer is obtained at 40 by weight of the dispersed phase since

its interaction parameter (Δb) found to be 00017

It is worth to mention that the PDXL content of 2SP1 is 30 and the length of the grafts is

half that of 2SP2 copolymer For this reason these two copolymers have been chosen for the

purpose of comparison in terms of side chains length

An optimization of the amount of copolymer needed for compatibilization of PSPEG (5050)

blend has been made (corresponding to Δb = 0) as function of the PDXL content and shown

in Table 14

Table 14 minimum amount of compatibilizer needed for compatibilization of PSPEG

(5050) vs PDXL content

Compatibilizer Δb Minimum Amount Needed PDXL Content wt dispersed phase wt of total blend

DXPS 0 9 43 71

2SP2 0 245 109 4025

2SP1 0 40 166 30

443 Optical Microscopy and Phase Morphology

PDXL is a perfect alternate copolymer of poly (ethylene oxide) (PEO) and poly (methylene

oxide) (PMO) that has the same curious combination properties as PEG So PDXL must be

at least miscible with PEG or adhere at the interface between PS and PEG and between

PMMA and PEG The compatibility between hydrophobic PS or PMMA and hydrophilic

PEG is very poor Compatibilization between components of the two sets of polymer blends is

studied by optical microscopy

The morphological characteristics of the blends by different compatibilizers are presented in

Figure 24 The optical microscopy micrographs of PSPEG blends without compatibilizers

show a poor dispersion for PS disperse phase and a ldquoball-and-socketrdquo topography due to the

poor interfacial adhesion between PEG matrix and the dispersed phase However with the

addition of compatibilizers the morphological characteristics of the polymer blends are

greatly altered It can be noticed that for these two different blends the particle size of PS

domains gets progressively much smaller and uniform in compatibilized blends than in

incompatibilized ones This may be explained by the significant increase of the phase

interfacial adhesion Consequently the domain size strongly depends upon the

compatibilizers used

a) PSPEG (5050) 0 (without compatibilizer)

DXPS 10 DXPS 20 DXPS 30 DXPS 40 b) Compatibilizing effect of DXPS copolymer

2SP2 10 2SP2 20 2SP2 30 2SP2 40 c) Compatibilizing effect of 2SP2 copolymer

2SP1 40

d) Compatibilizing effect of 2SP1copolymer at 40 addition

Figure 24 Optical micrographs showing phase structure in 5050 PSPEG blends

a) blends without compatibilizer b) with DXPS c) with 2SP2 d) with 40 of 2SP1

For instance the PSPEG blends with the incorporation of the copolymers DXPS 2SP2 and

2SP1 as compatibilizers (Figure 24) the morphology displays a very fine dispersion of PS

phase and strong interfacial adhesion with PEG Matrix The good compatibilizing effect

mainly that of DXPS can be explained by two mechanisms

First the PDXL units in the compatibilizer interact with PEG ether groups leading to a good

adhesion at interface between the components of the blend In addition hydrogen bonding

may also exist between PDXL and PEG further increasing compatibilization Second since

the compatibilizer also contains styrene blocks it contributes to provide a good compatibility

with PS Consequently the remarkable compatibilizing effect of PS-g-PDXL copolymers

induced a drastic decrease in interfacial tension and suppression of coalescence between the

originally immiscible polymer phases

As it can be noticed from the micrographs given in the figure above the compatibilizer

exhibits finer dispersion and homogeneous morphology of the blends as the amount of

compatibilizers increases

Eventually each compatibilizer has its own effect on the immiscible blends depending on the

amount of PDXL (side chains) and number of grafts present in the copolymers

By comparing micrographs shown in Figure 24 b and c the compatibilization effect of DXPS

copolymer which contains more grafts but shorter is different from that of the 2SP2

copolymer In the case of DXPS it is observed that the size of the dispersed droplets is

deceased significantly and results in finer dispersion morphology However 2SP2 copolymers

shows an improvement in compatibility of the blend after addition up to 30 wt of the

dispersed phase (13 total weight of the blend) exhibits homogeneous morphology This

may be related to length of the grafts In all cases these copolymers act as good

compatibilizers for the blend of 5050 wt PSPEG

444 FTIR Analysis

The FTIR technique is very important since it allows one to study the specific interactions

between the polymers The knowledge of the polymerndashpolymer interactions will be useful for

studies of the compatibility in polymer blends To verify the intermolecular interactions that

can play a role in miscibility the vibrational spectra of the blends studied in the present work

were obtained In polymeric systems where there are multiple interactions vibrational bands

such as ν (C=O) ν (COC) and ν (OH) present contributions of spectroscopic free and

associated forms

In order to elucidate the role played by intermolecular interactions in the miscibility of these

blends FTIR absorption of individual polymer components PS PEG and PMMA and

compared to that of the mixtures Figures 26 27 and 28 present the FTIR absorption spectra

from 4000 to 400 cm-1 for all samples

In the case of PS the high-frequency infrared spectra consist of seven absorption bands The

bands with peak locations at 3008 3026 3060 3082 and 3103 cm-1 are due to C-H stretching

of benzene ring CH groups on the PS side-chain The bands with peak positions of 2924 and

2850 cm-1 are due to the C-H stretching vibration of the CH2 and CH groups of the main PS

chain respectively PEG with molecule chemical structure of HO-[CH2-CH2-O]n-H exhibits

important absorption bands from FTIR spectroscopy measurements as shown in Figure 25 It

was verified contributions associated with CndashOndashC symmetric stretching of ether groups218-220

221 from 1050 to 1150 cm-1 with maximum peak at 1150 cm-1 Characteristics CH2-O

stretching modes from 2800-3000 cm-1 are observed214 At low frequency region peaks at 850

and 890 cm-1 are assigned to CndashOndashC stretching and at 500 cm-1 ascribed to CndashOndashC

deformation The presence of PDXL in the blends is detected by the intense frequency at 1140

cm-1 which is assigned for acetal groups In addition both PDXL and PEG contain ether

groups and the spectra show that the corresponding peaks are overlapped for the blends The

intensity of the side bands at 1144 and 1062 cm-1 decreases due to the decrease of PEG

crystallinity in the blends222

218 Sahlin JJ and Peppas NA J Appl Polym Sci63 (1997) 103ndash10 219 Roberts MJ Bently MD and Harris J M Adv Drug Deliv Rev 54 (2002) 459ndash76 220 Chiavacci LA Dahmouche K Santilli CV Bermudez Z Carlos LD Briois V and Craievich AF J Appl

Cryst 36 (2003) 405ndash9 221 Coates J In Meyers RA editor ldquoEncyclopaedia of analytical chemistryrdquo Chichester Wiley (2000) 10815ndash

37 222 Fox TG J Appl Bull Am Phys Soc 1 (1956) 123 223 JD Thomas MSc Thesis Sep 2001 Drexel University Novel associated PVAPVP hydrogels for nucleus

pulposus replacement Philadelphia PA USA 224 Hassan CM Peppas NA Adv Polym Sci 200015337ndash65 225 Peppas NA Polymer 197718403ndash8 226 Peppas NA Makromol Chem 1977178595ndash601

It can be observed also a typical large hydroxyl bands with two distinct contributions which

can be seen for all samples They are attributed to the spectroscopically free and bonded ndashOH

stretching forms at 3600-3800 cm-1 and 3200-3500 cm-1 respectively221 - 227

500 1000 1500 2000 2500 3000 3500 4000-05

PS and PEG PEG PS

Wave number (cm-1)

Figure 25 FTIR spectra of PS PEG over 4000-400 cm-1 range

227 Peppas NA Wright L Macromolecules 1996298798ndash804

500 1000 1500 2000 2500 3000 3500 4000

1DXPS IN PSPEG BLENDS

0 10 20 30 40

Wave number (cm-1)

Figure 26 FTIR spectra of PSPEG blends (5050) with different amounts of compatibilizer

(DXPS)

All these absorption bands for individual polymer were observed in the FTIR spectrum of the

5050 (ww) PSPEG in which they were combined to give superimposed bands in the regions

of 750-1500 cm-1 and 2700- 3100 cm-1

The hydroxyl vibrational frequency is discernible in the blend spectrum for PSPEG at 0

With the incorporation of the copolymers for compatibilization a number of bands showed

small shifts and changes in position and shape in the resulting spectra In Figures 28 29 and

30 as it can be noticed that in the hydroxyl absorption region a decrease in the fraction of

free OH groups is observed as the amount of copolymers is increased in the blend This can

be due to the flexibility of the PDXL graft chains on the other hand to the acetal and ether

groups of PDXL which are probably randomly distributed among an increasing number of

hydroxyl groups of PEG statistically favoring the formation of the PDXL and PEG hydrogen

bond interaction The results indicate that the intermolecular hydrogen bonding between the

ether oxygen of PDXL and the hydroxyl groups of PEG may be formed thereby reducing the

fraction of free OH which is consistent with the shifts observed in the region of hydroxyl

stretching Intermolecular hydrogen bondings are expected to occur among PDXL and PEG

chains due the high hydrophilic forces These interactions have replaced the intramolecular

interactions between COC and OH groups of PEG before addition of containing PDXL

copolymers It can be noticed a progressive shift of hydroxyl band from 3340 to 3420 cm-1

with DXPS and from 3340 to 3350 cm-1 when 2SP2 is added This shift can be attributed to

the decrease of intramolecular interactions among hydroxyl groups within PEG chains in

favor to intermolecular interactions between PDXL and PEG228

500 1000 1500 2000 2500 3000 3500 4000

2SP2 IN PSPEG BLENDS 0 10 20 30 40

Wave number cm-1

(2SP2)

228 Daniliuc L David C and De Kesel C Eur Polym J 11 1992) 1365ndash71

3200 3300 3400 3500 3600 3700 3800

DXPS IN PSPEG BLENDS 0 10 20 30 40

Wave number (cm-1)

(DXPS) in the hydroxyl absorption region

3200 3300 3400 3500 3600 3700 3800

Wave number cm-1

(2SP2) in the hydroxyl absorption region

3200 3300 3400 3500 3600 3700 3800

DXPS 40 2SP2 40 2SP1 40

Wave number (cm-1)

Figure 30 FTIR spectra comparison of PSPEG blends (5050) with different compatibilizers

in the hydroxyl absorption region

Conclusions An effective strategy for compatibilization of two kinds of immiscible polymer blends has

been demonstrated Compared with PS-g-PDXL with DXPS content the DXPS is more

effective binary polymer blends compatibilizer in the PSPEG blends which is due to the high

number of grafts and high PDXL content This has led to good adhesion of PDXL chains with

the PEG phase in the blends Again The PS blocks of the copolymer result in good

compatibility with PS component of the blends The compatibilization of PSPEG blends is

apparently associated with hydrogen bonding where groups of the acetal units in PDXL

interact with hydroxyl groups of PEG These form a stronger interface between the two

phases which leads to important modifications of the blend properties Apparently the FTIR

result is in good agreement with the miscibility criteria proposed by Krigbaum and Wall (Δb)

interaction parameter which results from dilute-solution viscometry (DSV) method It can be

concluded that by the addition of 20ndash40 wt of incorporated copolymer reveal a good

compatibilizing efficiency for the blend systems as it was observed from micrographs as well

References

174 Paul D R and Newman S Eds ldquoPolymer Blendsrdquo Academic Press New York Vol I-II (1979) 175 Noshay A and McGrath J E ldquoBlock Copolymers-Overview and Surveyrdquo Academic Press New York

(1977) 176 Olabisi O Robeson L M and Shaw M ldquoPolymer-Polymer Miscibilityrdquo Academic Press New York

(1979) 177 L A Utracki ldquoPolymer Alloys and Blends Thermodynamic and Rheologyrdquo Hanser

Publishers Munich (1989) 178 Flory P J Principles of Polymer Chemistry Cornell Ithaca NY (1953) 179 Scott R L J Chem Phys 17 (1949) 279 180 Hildebrand J H and Scott R L ldquoThe Solubility of Non-electrolytesrdquo 3rd ed Reinhold Publishing Corp

L Estes G 182 Paul D R Bucknall C B ldquoPolymer Blendsrdquo Wiley New York (1999) 183 D R Paul J W Barlow and H Keskula in J I Kroschwitz ed-in-ch ldquoEncyclopedia of Polymer Science

and Engineeringrdquo 2nd ed Wiley-Interscience New York (1985) 184 G P Hellmann and M Dietz Macromol Symp 170 (2001) 185 60 B D Gesner ldquoEncyclopedia of Polymer Science and Technologyrdquo Interscience New York Vol 10

(1969) 694ndash709

186 R D Deanin in H F Mark N G Gaylord and N M Bikales eds ldquoEncyclopedia of Polymer Science and

Technologyrdquo Suppl Wiley-Interscience New York Vol 2 (1977) 458 187 J Schies and D B Priddy eds ldquoModern Styrenic Polymers Polystyrene and Styrenic Copolymersrdquo John

(1981) 189 BD Favis in D R Paul and C B Bucknall eds Polymer Blends Vol 1 Formulations John Wiley amp Sons

Inc New York Chap 16 (2000) 190 Herold CB Keil K Bruns DE Biochem Pharmacol 38 (1989) 73 192 CChorng-Shyan Cheng-kang Lee and Kuan-chaung Lin Journal of Polymer Research 13 (2006) 247-254 193 Y Hua YS Hua V Topolkaraevb A Hiltnera E Baera Polymer 44 (2003) 5681ndash5689 194 S P Timg B J Bulkin and E M Pearce J Polym Ser Polym Chem 19 (1981) 451 195 T Suzuki Y Murakami T lnm and Y Takenam]

Poljmer J 13 1027 (1981) 196 Norimasa Watanabe Isamu Akiba and Saburo Akiyama Europ Polymer Journal 37 (2001) 1837-1842 197 HJ Rhoo HT Kim JK Park TS Hwang Electrochim Acta 42 (1997) 1571 198 B Oh YR Kim Solid State Ionics 124 (1ndash2) (1999) 83 199 K Pielichowski Eur Polym J 35 (1999) 27 200 AM Stephen TP Kumar NG Renganathan S Pitchumani R Thirunakaran and N Muniyandi J Power

Sources 89 (2000)80 201 JL Acosta E Morales Solid State Ionics 85 (1996) 85 202 AM Rocco RP Pereira MI Felisberti Polymer 42 (2001)5199 203 AV Rajulu RL Reddy SM Raghavendra and SA Ahmed Eur Polym J 35 (6) (1999) 1183 204 W Wu X Luo D Ma Eur Polym J 35 (1999) 985 205 Krause S ldquoPolymer-polymer compatibilityrdquo in PolymerBlends Vol 1 ed D R Paul and S Newman

Academic Press NY (1978) 206 Kulshreshta AK Singh B P and Sharma Y N Eur Polym J 24 (1988) 29 207 Z Pingping Y Haiyang Z Yiming Eur Polym J 35 (1999) 915 208 Mikhailov NV and Zeilkman SG Kolloid Z 19 (1957) 465 209 Bohmer B Berek D and Florian S Eur Polym J 6 (1970) 471 210 Feldman D and Rusu M EurPolym J 6 (1970) 627 211 Krigbaum W R and Wall F J Journal of Polym Sci 5 (1950) 505 212 Catsiff E H and Hewett W A J Appl Polym Sci 6 (1962) 530 213 Kulshreshta AK Singh B P and Sharma Y N Eur Polym J 2 (1988) 191 214 ML Huggins J Am Chem Soc 64 (1942) 116 215 E Schroder G Muller and KF Arndt ldquoLeitfaden der PolymerCharakterisierungrdquo Akademie Verlag Berlin

(1982) 216 Garcia R Melad O Gomez C M Figueruelo J E and Campos A Eur Polym J 35 (1999) 4 217 Melad O Asian J of Chem 14 (2002) 849 218 Sahlin JJ and Peppas NA J Appl Polym Sci63 (1997) 103ndash10

219 Roberts MJ Bently MD and Harris J M Adv Drug Deliv Rev 54 (2002) 459ndash76 220 Chiavacci LA Dahmouche K Santilli CV Bermudez Z Carlos LD Briois V and Craievich AF J Appl

pulposus replacement Philadelphia PA USA 224 Hassan CM Peppas NA Adv Polym Sci 200015337ndash65 225 Peppas NA Polymer 197718403ndash8 226 Peppas NA Makromol Chem 1977178595ndash601 227 Peppas NA Wright L Macromolecules 1996298798ndash804 228 Daniliuc L David C and De Kesel C Eur Polym J 11 1992) 1365ndash71

CHAPTER V Compatibilization Effect of Poly (Methyl Methacrylate-g-

Poly (1 3 Dioxolane)) on Immiscible Polymer Blends of

Polystyrene and Poly (Ethylene Glycol)

51 Introduction

PMMA is more than just plastics of paint Often lubricating oils and hydraulic fluids tend to

get really viscous and even gummy when they get cold This is a real pain when operating

heavy equipments in very cold weather When a little bit of PMMA is dissolved in these oils

and fluids they donrsquot get viscous in the cold and machines can be operated down to -100degC

PMMA can find a several applications namely adhesive optical coating medical packaging

applications and so forthhellip

In medical applications PMMA and its derivatives are used particularly for hard tissue repair

and regeneration229 PMMA beads have been developed to deliver aminoglucoside antibiotics

locally for the treatment of bone infections230 PMMA and PEG form an important and unique

pair of polymers in that they are chemically different In the present work this study may

shed light on the PMMA properties modifications induced by blending with PEG to overcome

the difficult processing of rigid PMMA

Several studies have been made on blends of poly (ethylene oxide) PEO and PMMA in the

last decades but very few on PMMAPEG blends231 232 233

Numerous works reported that the miscibility domain ranges between 10 and 30 of PEO by

weight depending on the PMMA tacticity or molecular weight No phase diagram is available

yet in the literature for PMMAPEO and neither it is for PMMAPEG234

229 M Sivakumar KP Rao Reactive Funct Polym 46 (2000) 29 230 AJDomb Polymeric Site Specific Pharmacotherapy Wiley New York (1994) 243 231 Schants S Macromolecules 30 (1997) 1419 232 Chen X Yin J Alfonso G C Pedemonte E TurturroA And Gattiglia E Polymer 39 (1998) 4929 233 Parizel N Laupetre F and Monnerie L Polymer 30 (1997) 3719 234 L Hamon Y Grohens A Soldera and Y Holl Polymer 42 (2001) 9697-9703

52 Experimental

521 Materials

PEG and PMMA were used as blend components PMMA was obtained from ENPC TP1-

Chlef Company PEG was purchased from MERCK Company Physical and Structural

characterizations of these materials were performed by SEC 1H-NMR and DSC

Blends of PMMAPEG (5050) were prepared using the same procedure as described for the

blends discussed in the previous chapter Table 15 shows the quantities of the copolymers

used for compatibilization of the blends of PMMAPEG

PMMAPEG

10 20 30 40

47 9 13 166

533 FTIR FTIR measurements were performed on a Bruker IFS 66S Fourier transform spectrometer at

541 Characterization of the Homopolymers

The polymers have been analyzed by SEC to determine their number average-molecular

weights and polydispersity indices DSC measurements performed to determine their glass

transition temperatures as well as melting point of crystallinity of PEG 1HNMR spectroscopy analysis revealed the tacticity of PMMA It has been found that PMMA

is Syndiotactic-Atactic (highly syndiotactic) as shown in Figure 3 and 321

Physical characteristics of materials used are given in Table 16

Materials

Mw gmol

degC Tm range

degC Crystallinity

PMMA ENPC TP1-Chlef (fromLG MMA Corp)

55 000

PEG Merck

35 000

60 ndash 65

Figure 31 1H-NMR spectrum of Commercial PMMA (ENPC TP1-Chlef) in CDCl3

Figure 32 1H-NMR spectrum of Commercial PMMA (ENPC TP1-Chlef) in the methyl shifts

region in CDCl3

542 Dilute Solution Viscometry

Dilute solution viscometry has been utilized to evaluate miscibility of PMMAPEG blends

and the same approach discussed in the previous section has been followed The

experimental reduced viscosities of the polyblends are plotted against concentration in dilute

solution viscometry Eventually plots of pure polymers and polyblends of 5050 PMMAPEG

are first obtained Then their interaction coefficients are determined as shown in Table 17

Table 17 Interaction coefficient for binary solutions (polymersolvent)

Blend components PEG PMMA

b11 007327 minus

b22 minus 006561

b12 = (b11 b22)12 = 006933 (theo)

The compatibility of this system has been evaluated through the sign of Δb The values of the

latter according to equation 73 for different amounts of poly (MMA-g-PDXL) copolymers in

the blends are given in Table 18 It is observed that the blend of PMMAPEG at 5050 by

weight shows a negative value of Krigbaum and Wall parameter which indicates

incompatibility of the system as it is expected Similarly to PSPEG blend a crossover in the

reduced viscosity-concentration plot is observed and a decrease of slope arises in the range of

05 to 066 gdl in the viscosity-concentration plot as shown in Figure 33 This is attributed to

the repulsive intermolecular interactions between the polymer chains

Then the incorporation of the copolymers at various amounts presents positive values

progressively Curves of reduced viscosity (ηspc) vs concentration for PMMAPEG blends in

THF at 30degC with various amounts of copolymer are given in Figures 34 35 and 36

Table 18 Interactions parameters for PMMAPEG blends with poly (MMA-g-PDXL)

copolymers (3MP2 2MP2 and 3MP1) as compatibilizers

0 10 20 30 40

3MP2 b12 00288 01308 01904 02373 02602

Δb - 004053 00615 01211 01680 01909

2MP2 b12 00288 01286 01690 01893 02296

Δb - 004053 00593 00997 01200 01603

3MP1 b12 00288 00868 01670 02010 02379

Δb - 004053 00175 00977 01317 01686

00 01 02 03 04 05 06 07 08 09 10 11020

040PMMAPEG (5050) 0

PEG PMMAPEG 0 PMMARe

C (gdl)

Figure 33 Plots of reduced viscosity (ηspc) vs concentration for PMMA PEG and

PMMAPEG blend (0) in THF at 30degC

02 03 04 05 06 07 08 09 10 11000

040 BLENDS WITH 3MP1

PMMAPEG 0 10 20 30 40 Re

C (gdl)

Figure 34 Plots of reduced viscosity (ηspc) vs concentration for PMMAPEG blends in THF

at 30degC with various amounts of 3MP1 copolymer

02 03 04 05 06 07 08 09 10 11010

045BLENDS WITH 3MP2

PMMAPEG 0 10 20 30 40

C (gdl)

02 03 04 05 06 07 08 09 10 11010

040BLENDS WITH 2MP2

PMMAPEG 0 10 20 30 40 Re

C (gdl)

From our viscosity data as the copolymer content increases in the blend the polymer blend

molecules will become disentangled more spaciously resulting in a greater interaction

between structurally similar component segments This suggests that there are attractive

forces that induce miscible behavior of the blends as it is observed in Figure 37

0 10 20 30 40 5-01

PMMA PEG BLENDS

3MP2 2MP2 3MP1

copolymers (3MP2 2MP2 and 3MP1) used for compatibilization

The three copolymers (3MP2 2MP2 and 3MP1) involved in this study for compatibilization

are different from the point of view of the PDXL content and the graft length For instance

3MP2 and 2MP2 have similar and longer grafts since the theoretical number average-

molecular weight of the graft is 2000 gmol However they contain different amount of

PDXL In the case of 3MP1 this graft copolymer has a structure with shorter side chain length

(Mn = 1000 gmol) corresponding to the half of the graft size in the former copolymers From

the observations made out of the figure above 3MP2 copolymer (21 w of PDXL) provides

higher values of the interaction parameter and therefore greater extent of compatibility

compared to the other copolymers since it has long grafts which allows penetration into the

other phase

It can be concluded that all three copolymers show good results for compatibilization on the

basis of the Δb criterion of polymer-polymer miscibility determined by viscometry

Similarly the minimum amount of copolymer needed for compatibilization of PSPEG

(5050) blend has been determined corresponding to Δb = 0 as function of the PDXL content

and shown in Table 19

(5050)

2MP2 0 34 16 35

3MP2 0 37 18 21

3MP1 0 58 28 19

a) PMMAPEG (5050) 0 (without compatibilizer)

b) Compatibilizing effect of 2MP2 copolymer

c) Compatibilizing effect of 3MP2 copolymer

d) Compatibilizing effect of 3MP1copolymer

Figure 38 Optical micrographs showing phase structure in 5050 PMMAPEG blends

a) blends without compatibilizer b) with 2MP2 c) with 3MP2 d) with 3MP1

Figure 38 presents microscopy images of PMMAPEG blends with varying amounts of

compatibilizers The morphological characteristics of the blends of PMMAPEG without

compatibilizers show a poor dispersion of PMMA as a dispersed phase The addition of

compatibilizers changes drastically the morphological topology of this system The

compatibilizers used are of different length of the side chains and also different PDXL

content By introducing progressively variable amounts of the compatibilizers they display

similarly the morphological characteristics to some extent It is observed that the phase

separated domains of PMMA in the blends are reduced with increasing amounts of the

compatibilizers This is due to the compatibility of PMMA of the copolymers with the

PMMA blend component and on the other hand to the interfacial interactions of the PDXL

of the copolymers and PEG component of the blends From these results it is revealed that

compatibilizing effect of 2MP2 copolymer on this system is great compared to the others Not

only causes the size of the dispersed droplets to decrease but also dispersed droplets become

homogeneous However 3MP1 copolymer which contains shortest grafts (about half length

of those of the other copolymers) and less amount of PDXL shows less reduction in the

droplet size compared to the other copolymers Therefore it can be concluded that the

compatibilization of this blend depends upon length and number of grafts

On the overall observations these compatibilizing copolymers are very effective and hence

influence and improve the compatibility of PMMAPEG blend at a composition of 5050 wt

544 FTIR Analysis

Same observations can be made for the blends of PEG with PMMA The FTIR spectrum of

this blend at 0 compatibilizer is shown in Figure 39 For pure PMMA the

spectroscopically free carbonyl group band is observed at 1730 cm-1 In the blend sample one

large vibrational band due to hydroxyl group stretches in pure PEG is observed with two

distinct contributions which can be seen for all samples They are attributed to the

spectroscopically free and associated hydroxyl forms at 3495 and 3600 cm-1 respectively

A large band in the wave number range of 1400-1500 cm-1 is assigned to the deformation

vibration of the methyl groups The bands with peaks locations at 2820 and 2990 cm-1 are due

to C-H symmetrical and asymmetrical stretching vibration of CH3 respectively Peaks at

2886 and 2950 cm-1are ascribed to C-H symmetrical and asymmetrical stretching vibration of

CH2 figures 40 and 41 The C-O band is observed in the range of 1150- 1210 cm-1

500 1000 1500 2000 2500 3000 3500 4000

20 PMMAPEG 0 Blend

Wave number cm-1

Figure 39 FTIR spectra of PMMAPEG 0 over 4000-400 cm-1 range

2750 2800 2850 2900 2950 3000 3050 3100-05

PEG PMMAPEG 0

Wave number cm-1

Figure 40 FTIR spectra of PMMAPEG 0 and PEG over the 3100-2700 cm-1 range

2750 2800 2850 2900 2950 3000 3050 3100

152MP2 in PMMAPEG

0 10 20 30 40

Wave number cm-1

Figure 41 FTIR spectra of PMMAPEG 0 blends with 2MP2 addition over the 3100-2700

cm-1 range

The incorporation of PMMA-g-PDXL copolymers in the blends makes some changes in the

resulting spectra as it can be noticed in Figures 42 - 44 In the hydroxyl absorption region

same phenomenon has occurred as in the PSPEG blends The fraction of free OH groups has

decreased as the amount of the copolymers increased as shown in figures 45 and 46 which

present the effect of different compatibilizers in the hydroxyl absorption region This can be

explained as discussed above by the fact that the PEG hydroxyl groups undergo other

intermolecular interactions essentially with PDXL chains of the copolymers A comparison of

the effect of the three copolymers involved in the compatibilization at the highest amount

added is given in figure 47 It can be noticed that 2MP2 shows very few fraction of free OH

groups compared to the others This copolymer contains more PDXL (35 wt with 4 grafts)

than the others do (21 wt with 3 grafts and 19 wt with 3 grafts in 3MP2 and 3MP1

respectively)

A crystalline PEG phase is confirmed by the presence of the triplet peak of the COC

stretching vibration at 1148 1110 and 1062 cm-1 with a maximum at 1110 cm-1235 236

Changes in the intensity shape and position of the COC stretching mode are associated with

235 Li X and Hsu SL J Polym Sci Polym Phys Ed22 (1984) 1331 236 Bailey JrF E and Koleske JV Poly (ethylene oxide) New York AcademicPress (1976) 115

the interaction between PEG and PMMA-g-PDXL In addition both polymers contain the

same ether group and the spectra show that the corresponding peaks are overlapped for the

blends The intensity of the side bands at 1144 and 1062 cm-1 decreases due to the decrease of

PEG crystallinity in the blends237

Therefore the presence of this interacting system is probably responsible for the miscibility

and low degree of crystallinity observed for these blends

500 1000 1500 2000 2500 3000 3500 4000

202MP2 in PMMAPEG BLENDS

0 10 20 30 40

Wave number cm-1

Figure 42 FTIR spectra of PMMAPEG blends (5050) with different amounts of

compatibilizer (2MP2)

237 Fox TG J Appl Bull Am Phys Soc 1 (1956) 123

500 1000 1500 2000 2500 3000 3500 4000

20 3MP2 IN PMMAPEG BLENDS 0 10 20 30 40

Wave number cm-1

500 1000 1500 2000 2500 3000 3500 4000

Wave number cm-1

3MP2 IN PMMAPEG BLENDS 0 10 20 30 40

Wave number cm-1

compatibilizer (3MP2) in the hydroxyl absorption region

3100 3150 3200 3250 3300 3350 3400 3450 3500 3550 3600 3650 3700 3750 3800

3MP1 IN PMMAPEG 40 30 20 10 0

Wave number cm-1

2MP2 40 3MP2 40 3MP1 40

Wave number cm-1

Figure 47 FTIR spectra comparison of PMMAPEG blends (5050) with different

compatibilizers in the hydroxyl absorption region

The results from FTIR spectra indicate the compatibility of these polymer blends with the

addition of the PDXL copolymers via hydrogen bonds is observed and confirmed mainly by

the shifts of bands of the hydroxyl stretching modes

Conclusions

From the observations made out from this study reveal that all three copolymers show good

results for compatibilization on the basis of the Δb criterion of polymer-polymer miscibility

determined by viscometry Therefore these copolymers act as good compatibilizers since it

was found that the minimum amount needed for compatibilizing is between 1 to 3 of the

total weight of the blend which corresponds to 3 to 6 of the dispersed phase This

compatibilization is due to the fact that the copolymers have constituents which present strong

interactions with both polymer components of the blends These results are in great agreement

with microscopy analyses which demonstrate that the phase separated domains of PMMA in

the blends are reduced with increasing amounts of the compatibilizers This is due to the

compatibility of PMMA of the copolymers with the PMMA blend component and on the

other hand to the interfacial interactions of the PDXL of the copolymers and PEG component

of the blends

From FTIR results obtained in this work copolymers containing large amount of PDXL is

effective as compatibilizing agent for PMMAPEG blends It is pointed out that

compatibilizing effects of these copolymers are caused due to the associative interactions

between ether groups of PDXL grafts and hydroxyl groups of PEG and miscibility between

PMMA and relatively long PMMA backbone of PMMA-g-PDXL copolymers respectively

These compatibilizing copolymers are very effective and hence influence and improve the

compatibility of PMMAPEG blend at a composition of 5050 wt

References 229 M Sivakumar KP Rao Reactive Funct Polym 46 (2000) 29 230 AJDomb Polymeric Site Specific Pharmacotherapy Wiley New York (1994) 243 231 Schants S Macromolecules 30 (1997) 1419 232 Chen X Yin J Alfonso G C Pedemonte E TurturroA And Gattiglia E Polymer 39 (1998) 4929 233 Parizel N Laupetre F and Monnerie L Polymer 30 (1997) 3719 234 L Hamon Y Grohens A Soldera and Y Holl Polymer 42 (2001) 9697-9703 235 Li X and Hsu SL J Polym Sci Polym Phys Ed22 (1984) 1331 236 Bailey JrF E and Koleske JV Poly (ethylene oxide) New York AcademicPress (1976) 115 237 Fox TG J Appl Bull Am Phys Soc 1 (1956) 123

CONCLUSIONS

Monomer mechanism proposed by Franta and Reibel using an unsaturated alcohol (2-

HPMA) as a transfer agent results in linear polymeric chains in order to prevent formation of

cyclic oligomers through cationic polymerisation of cyclic acetals They were all prepared at

the same reaction conditions

The characterization of these macromonomers has been conducted using different methods of

analysis Structure and molecular weight determination were provided from SEC and Raman

and 1H-NMR spectroscopy

We were interested in obtaining a hydrogel based on fully PDXL segments and study its

swelling and viscoelastic behaviour The hydrogel has combined special properties The

results reveal a perfect elastic and resistant hydrogel with interesting viscoelastic properties

composition of the copolymers Structure composition and number of grafts of the

copolymers were determined by SEC and 1H-NMR spectroscopy Another approach for

copolymerization has been made in order to compare the copolymers obtained from different

types of polymerization reactions like Conventional Free Radical and Controlled Radical

Polymerizations In the latter the copolymer obtained possesses larger number of grafts than

those from the former

The macromonomer reactivity estimation suggests that the length of the PDXL side chains

does affect the reactivity of the methacrylic double bond of the macromonomer when

copolymerized with St However in the case of copolymerization with MMA there is no

dependence on the graft size Finally from DSC measurements the values of Tg depend on

the composition and the size of the PDXL grafts In all copolymers the increase in amount of

the incorporated PDXL macromonomer results in a substantial decease in glass transition

An effective strategy for compatibilization of two kinds of immiscible polymer blends has

the PEG phase in the blends

The compatibilization effect of the copolymers used in this study on the PSPEG and

PMMAPEG was demonstrated from the viscometric results The contribution of both PS or

PMMA and PDXL of the copolymers has played a big role in the compatibilization of these

two different systems of blends thereby resulting in good compatibility due the chemical

affinity between these components which leads to a drastic decrease in interfacial tension and

suppression coalescence between the blend constituents

It has been shown that the immiscible blends in question exhibit compatibility when small

amount of copolymers synthesized for this purpose are added except for one of them

Styrene-g-PDXL copolymers act as good compatibilizers for PSPEG blends since it was

found that the minimum amount needed for compatibilizing is less than 11 of the total

weight of the blend which corresponds to 25 of the dispersed phase This compatibilization

is due to the fact that the copolymers have constituents which present strong interactions with

both polymer components of the blends

Compared with PS-g-PDXL with DXPS content the DXPS is more effective binary polymer

blends compatibilizer in the PSPEG blends which is due to the high number of grafts and

high PDXL content This has led to good adhesion of PDXL chains with the PEG phase in the

blends Again The PS blocks of the copolymer result in good compatibility with PS

component of the blends The compatibilization of PSPEG blends is apparently associated

with hydrogen bonding where groups of the acetal units in PDXL interact with hydroxyl

groups of PEG These form a stronger interface between the two phases which leads to

important modifications of the blend properties

Similarly PMMA-g-PDXL copolymers act as good compatibilizers since it was found that

the minimum amount needed for compatibilizing is between 1 to 3 of the total weight of

the blend which corresponds to 3 to 6 of the dispersed phase This compatibilization is due

to the fact that the copolymers have constituents which present strong interactions with both

polymer components of the blends

These results are in great agreement with microscopy analyses which demonstrate that the

phase separated domains of PMMA and PS in their respective blends are reduced with

increasing amounts of the compatibilizers

Specific interactions between chemical groups of two blend components can play an

important role in polymer mixtures There is a range of such interactions of varying strengths

which has been identified in polymer blends and such interactions are generally defined for

small molecules It should be noted that the extension of this concept to polymers is not

always straightforward it is more difficult to identify interactions in polymers the

spectroscopy is more complex and molecular conformations are less certain This situation is

further complicated because researchers use different names and definitions to describe

similar interactions

FTIR investigation showed that these interactions have been observed through the changes in

IR absorption peaks of PS PEG and PMMA upon mixing with increasing amount of

compatibilizers in their blends which have given rise to a wide investigation

From these the results obtained in this work copolymers containing large amount of PDXL is

effective as compatibilizing agent for PSPEG and PMMAPEG blends It is pointed out that

PS or PMMA and relatively long PS or PMMA backbone of PS-g-PDXL and PMMA-g-

PDXL copolymers respectively

Binder2pdf

Binder1pdf

page de gardedoc

Acknowledgementsdoc

OUTLINEdoc









References helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 145

CONCLUSIONS helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip 146

SUMMARY lastdoc

traduction REacuteSUMEacutedoc

CHAPTER I apresdoc





CHAPTER II 2doc

21 Introduction



CHAPTER III Apdf


CHAPTER III Baapdf

CHAPTER III Bbpdf

CHAPTER III Bcpdf

CHAPTER IV LASTpdf


References

CHAPTER Vpdf


51 Introduction

References

CONCLUSIONSpdf

Acknowledgements

I would like to thank my advisor Prof S OULD KADA for his help and to

express my sincere gratitude to Prof A KRALLAFA for providing continuous support

to this work His expertise guidance and understanding were a significant help

throughout my work

Very special thanks are extended to Prof Jeanne FRANCOIS for allowing me

to use instruments in her laboratory and for numerous discussions suggestions and

valuable advices which were important contribution to this research

Special thanks and deep appreciation go to Mr G CLISSON for his patience

and help with SEC and DSC measurements

I also owe my sincere appreciation to Mr A KHOUKH for his help with NMR

measurements and important comments considering NMR spectra

I want to thank gratefully Prof M BELBACHIR and Dr A TAYEB for

support and help to this work

I also owe my thanks to Prof Z BOUTIBA and Miss A HADJ BRAHIM for

optical microscopy measurements

I also owe my thanks to Dr MHAMHA and Miss S CHAOUI for Rheological

measurements

To Mr YOUSFI (ENPC-Chlef) I want to thank for Polymer supply

I acknowledge Prof S HACINI Prof D BENACHOUR and Prof M

BELHAKEM who honored me in participating in the jury of my thesis

Special gratitude to my husband FOUAD for being a continuous source of

encouragements For that I doubt I will ever be able to convey my appreciation fully

Special Thanks are also given to my mother father sisters and daughters for

moral support

SUMMARY

chapter

REacuteSUMEacute

miscibles

nous mecircme

(incompatibles)

end groups

Scheme 1

Scheme 2

method12

Scheme 3

scheme 4

Scheme 4

(ethyleneimine) (7)

Scheme 5

Scheme 6

(1988) 127-144

Protonation

Acylation

R CO SbF6 +

OR CO O SbF6

Alkylation

Et3O BF4 +

OC2H5 Et2O BF4O +

Hydrogen transfer

C SbF6 +O

C SbF6H O+

O + O O+ H O SbF6

R O++R A O

O(CH2)4

A+O(CH2)4

O (CH2)4 O+[ ]n

A O (CH2)4[ ]n

AO ( CH2 )4

CF3 SO3CH3 +O

CH3 CF3SO3O

CF3SO3

CF3SO2OSO2CF3 nO

(CH2)4 O (CH2)4 n-3

O O CF3SO3 CF3SO3

O(CH2)4

(CH2)4 O(CH2)4 OH H

++ H2O

+ LiBr

Scheme 7

macromonomer

hydroxyl groups

Scheme 8

main chain57

Scheme 9

materials6263

Scheme 10

charge buildup

homopolymer84

polymers

1 Initiation

(AIBN)

(equation 1)

polymerization

the initiation

becomes

2 Propagation

3 Termination

follows

written as

propagation

expressed as

concentration is

period of time

Therefore

shown as

reactions93

Therefore

the copolymer58

different ways

into the copolymer

η = [ r1 + r2 α ] ξ minus r2 α (50)

η = G ( α + H ) (51)

ξ = H ( α + H ) (52)

methods101 102

the form

nanostructures

materials

(2002)

dependent

Scheme 11

equation

complete

Scheme 12

References

(1985) 461

Macromonomers

21 Introduction

22 Experimental

b) Monomer

polymerization

to be about 80

under vacuum

WdWs (57)

states respectively

macromonomer

acetals54

900 cmP

-1 and 2700 to 3000 cmP

-1 and 870-800 cmP

-1 145 and are

-1 ranges

2700 cmP

-1 Below 3000 cmP

found at 1720 cmP

-1P and 1340 cmP

polymerization

FPP1 135 1000 1120 1160 16 097

FPP15 2025 1500 1540 1550 16 099

FPP2 270 2000 2040 2100 16 097

0 200 400 600 800 1000 1200 1400 16000

THF CH2Cl2

Time (min)

10-5 10-4 10-3 10-2 10-1 100 101 102101

Guns Guns Gs Gs

(hollow symbols)

frequencies

100 101

Gs Guns Gs GunsG

ω (rads)

100 101 102 103

ηlowast (P

ω (rads)

Conclusion

References

554 (2000) 99-108

31 Introduction

32 Experimental

b) Monomer

pressure

Scheme 14

Styrene (g) (mol)

AIBN (g)

THF (ml)

Conc (moll)

Scheme 16

respectively

Scheme 18

MMA (g) (mol)

AIBN (g)

THF (ml)

Conc (moll)

2MP15 FPP15 20 2 133 10-4 28 280 10-2 005 25 100 3MP15 FPP15 30 187 125 10-4 3744 374 0-2

006 60 0644 5MP15 FPP15 50 112 748 10-4 3744 374 10-2 005 60 0636

2MP1 FPP1 20 2 20 10-4 400 4 10-2

006 50 0840 3MP1 FPP1 50 125 125 10-4 3744 374 10-2 005 64 0604 5MP1 FPP1 80 075 748 10-4 3744 374 10-2 005 60 0636

chains

Sample

M1 in the feed

wt() mol()

M1 in the copolymer

wt() mol()

Mn SEC

Sample

M1 in the feed

wt() mol()

M1 in the copolymer

wt() mol()

Mn SEC

copolymer

Ng Graft

32 700

83 000

][ ][ ]

[ ][ ]

[ ] [[ ] [ ]221

MrMMMr

[ ][ ] 1

[ ] [ ][ ][ ] 01

2 lnlnMM

rMM tt =

Sample M2 M1

macromer Mnth

r2 1r2

SP2 St FPP2 2000 012 plusmn 0006 833

SP15 St FPP15 1500 0042 plusmn 6 10-4 238

SP1 St FPP1 1000 0015 plusmn 3 10-4 6666

MP15 MMA FPP15 1500 007 plusmn 0 02 1428

MP1 MMA FPP1 1000 0018 plusmn 001 5555

2] t[M

ln[M1]tln[M1]0

r2 = 0015 plusmn 3 10-4 SP1

r2 = 0042 plusmn 6 10-4

2] t[M

ln[M1]tln[M1]0

r2= 012 plusmn 0006

2] t[M

ln[M1]tln[M1]0

(a) SP1 (b) SP15 (c) SP2

2] t[M

ln[M1]tln[M1]0

r2 = 0018 plusmn 001 MP1

2] t[M

ln[M1]tln[M1]0

r2 = 007 plusmn 002MP15

036788

2] t[M

ln[M1]tln[M1]0

r2 = 002 plusmn 001 MP2

(a) MP1 (b) MP15 (c) MP2

copolymers

5SP 1424 5671 1

5SP 152 5590 15

21 6739 5SP 2

303 4480 3SP 2

34 2665 2SP15

4025 2SP 4060 2

wt () (degC)

5MP 10 10545 1

5MP 13 8278 15

21 6576 3MP 2

22 7550 3MP 15

26 7013 2MP1

5 10 15 20 25 30 35 40 4520

SP COPOLYMERSTg

(degC)

10 15 20 2560

Tg (deg

MP COPOLYMERS

Conclusion

41 Background

411 Physical Blends

polymerization

Lewis acid-base etc

energy consumption

is limited

(1981)

42 Experimental

421 Materials

10 20 30 40

47 9 13 166

433 FTIR Analysis

Materials

Mw gmol

degC Tm range

degC Crystallinity

128 000

PEG Merck

35 000

60 ndash 65

a) Introduction

molecular scale203

b11 007327 minus

b22 minus 02117

b12 = (b11 b22)12 = 01245 (theo)

0 10 20 30 40

DXSP b12 003511 01295 01680 01833 01947

Δb - 00894 00050 00435 00588 00702

2SP2 b12 003511 009826 01052 01314 01515

Δb - 00894 - 00262 - 00193 00069 00270

02 03 04 05 06 07 08 09 10 11

PS PSPEG 0 PEG

C (dll)

02 03 04 05 06 07 08 09 10 1101

07BLENDS WITH DXPS

PSPEG 0 10 20 30 40 Re

ity η

C (gdl)

02 03 04 05 06 07 08 09 10 1101

08BLENDS WITH 2SP2

PSPEG 0 10 20 30 40 Re

ity η sp

C (gdl)

02 03 04 05 06 07 08 09 10 1101

PSPEG 0 2SP1 40 Re

ity η sp

C (gdl)

02 03 04 05 06 07 08 09 10 1100

DXPS 40 2SP2 40

2SP1 40

2SP1 40 2SP2 40 DXPS 40 Re

ity η

C (gdl)

copolymer

Figure 23

0 10 20 30 40 5

PS PEG BLENDS

2SP2 DXPS

in Table 14

DXPS 0 9 43 71

2SP2 0 245 109 4025

2SP1 0 40 166 30

2SP1 40

444 FTIR Analysis

associated forms

500 1000 1500 2000 2500 3000 3500 4000-05

PS and PEG PEG PS

Wave number (cm-1)

500 1000 1500 2000 2500 3000 3500 4000

0 10 20 30 40

Wave number (cm-1)

(DXPS)

of 750-1500 cm-1 and 2700- 3100 cm-1

500 1000 1500 2000 2500 3000 3500 4000

Wave number cm-1

(2SP2)

3200 3300 3400 3500 3600 3700 3800

Wave number (cm-1)

3200 3300 3400 3500 3600 3700 3800

Wave number cm-1

3200 3300 3400 3500 3600 3700 3800

DXPS 40 2SP2 40 2SP1 40

Wave number (cm-1)

References

(1969) 694ndash709

51 Introduction

52 Experimental

521 Materials

PMMAPEG

10 20 30 40

47 9 13 166

Materials

Mw gmol

degC Tm range

degC Crystallinity

55 000

PEG Merck

35 000

60 ndash 65

region in CDCl3

b11 007327 minus

b22 minus 006561

b12 = (b11 b22)12 = 006933 (theo)

0 10 20 30 40

3MP2 b12 00288 01308 01904 02373 02602

Δb - 004053 00615 01211 01680 01909

2MP2 b12 00288 01286 01690 01893 02296

Δb - 004053 00593 00997 01200 01603

3MP1 b12 00288 00868 01670 02010 02379

Δb - 004053 00175 00977 01317 01686

00 01 02 03 04 05 06 07 08 09 10 11020

040PMMAPEG (5050) 0

C (gdl)

02 03 04 05 06 07 08 09 10 11000

PMMAPEG 0 10 20 30 40 Re

C (gdl)

02 03 04 05 06 07 08 09 10 11010

045BLENDS WITH 3MP2

PMMAPEG 0 10 20 30 40

C (gdl)

02 03 04 05 06 07 08 09 10 11010

040BLENDS WITH 2MP2

PMMAPEG 0 10 20 30 40 Re

C (gdl)

0 10 20 30 40 5-01

PMMA PEG BLENDS

3MP2 2MP2 3MP1

other phase

(5050)

2MP2 0 34 16 35

3MP2 0 37 18 21

3MP1 0 58 28 19

544 FTIR Analysis

500 1000 1500 2000 2500 3000 3500 4000

20 PMMAPEG 0 Blend

Wave number cm-1

2750 2800 2850 2900 2950 3000 3050 3100-05

PEG PMMAPEG 0

Wave number cm-1

2750 2800 2850 2900 2950 3000 3050 3100

152MP2 in PMMAPEG

0 10 20 30 40

Wave number cm-1

cm-1 range

respectively)

500 1000 1500 2000 2500 3000 3500 4000

0 10 20 30 40

Wave number cm-1

500 1000 1500 2000 2500 3000 3500 4000

Wave number cm-1

500 1000 1500 2000 2500 3000 3500 4000

Wave number cm-1

3100 3150 3200 3250 3300 3350 3400 3450 3500 3550 3600 3650 3700 3750 3800

3MP1 IN PMMAPEG 40 30 20 10 0

Wave number cm-1

2MP2 40 3MP2 40 3MP1 40

Wave number cm-1

Conclusions

of the blends

CONCLUSIONS

Binder2pdf

Binder1pdf

page de gardedoc

Acknowledgementsdoc

OUTLINEdoc











SUMMARY lastdoc


CHAPTER I apresdoc





CHAPTER II 2doc

21 Introduction



CHAPTER III Apdf


CHAPTER III Baapdf

CHAPTER III Bbpdf

CHAPTER III Bcpdf

CHAPTER IV LASTpdf


References

CHAPTER Vpdf


51 Introduction

References

CONCLUSIONSpdf

SUMMARY

chapter

REacuteSUMEacute

miscibles

nous mecircme

(incompatibles)

end groups

Scheme 1

Scheme 2

method12

Scheme 3

scheme 4

Scheme 4

(ethyleneimine) (7)

Scheme 5

Scheme 6

(1988) 127-144

Protonation

Acylation

R CO SbF6 +

OR CO O SbF6

Alkylation

Et3O BF4 +

OC2H5 Et2O BF4O +

Hydrogen transfer

C SbF6 +O

C SbF6H O+

O + O O+ H O SbF6

R O++R A O

O(CH2)4

A+O(CH2)4

O (CH2)4 O+[ ]n

A O (CH2)4[ ]n

AO ( CH2 )4

CF3 SO3CH3 +O

CH3 CF3SO3O

CF3SO3

CF3SO2OSO2CF3 nO

(CH2)4 O (CH2)4 n-3

O O CF3SO3 CF3SO3

O(CH2)4

(CH2)4 O(CH2)4 OH H

++ H2O

+ LiBr

Scheme 7

macromonomer

hydroxyl groups

Scheme 8

main chain57

Scheme 9

materials6263

Scheme 10

charge buildup

homopolymer84

polymers

1 Initiation

(AIBN)

(equation 1)

polymerization

the initiation

becomes

2 Propagation

3 Termination

follows

written as

propagation

expressed as

concentration is

period of time

Therefore

shown as

reactions93

Therefore

the copolymer58

different ways

into the copolymer

η = [ r1 + r2 α ] ξ minus r2 α (50)

η = G ( α + H ) (51)

ξ = H ( α + H ) (52)

methods101 102

the form

nanostructures

materials

(2002)

dependent

Scheme 11

equation

complete

Scheme 12

References

(1985) 461

Macromonomers

21 Introduction

22 Experimental

b) Monomer

polymerization

to be about 80

under vacuum

WdWs (57)

states respectively

macromonomer

acetals54

900 cmP

-1 and 2700 to 3000 cmP

-1 and 870-800 cmP

-1 145 and are

-1 ranges

2700 cmP

-1 Below 3000 cmP

found at 1720 cmP

-1P and 1340 cmP

polymerization

FPP1 135 1000 1120 1160 16 097

FPP15 2025 1500 1540 1550 16 099

FPP2 270 2000 2040 2100 16 097

0 200 400 600 800 1000 1200 1400 16000

THF CH2Cl2

Time (min)

10-5 10-4 10-3 10-2 10-1 100 101 102101

Guns Guns Gs Gs

(hollow symbols)

frequencies

100 101

Gs Guns Gs GunsG

ω (rads)

100 101 102 103

ηlowast (P

ω (rads)

Conclusion

References

554 (2000) 99-108

31 Introduction

32 Experimental

b) Monomer

pressure

Scheme 14

Styrene (g) (mol)

AIBN (g)

THF (ml)

Conc (moll)

Scheme 16

respectively

Scheme 18

MMA (g) (mol)

AIBN (g)

THF (ml)

Conc (moll)

2MP15 FPP15 20 2 133 10-4 28 280 10-2 005 25 100 3MP15 FPP15 30 187 125 10-4 3744 374 0-2

006 60 0644 5MP15 FPP15 50 112 748 10-4 3744 374 10-2 005 60 0636

2MP1 FPP1 20 2 20 10-4 400 4 10-2

006 50 0840 3MP1 FPP1 50 125 125 10-4 3744 374 10-2 005 64 0604 5MP1 FPP1 80 075 748 10-4 3744 374 10-2 005 60 0636

chains

Sample

M1 in the feed

wt() mol()

M1 in the copolymer

wt() mol()

Mn SEC

Sample

M1 in the feed

wt() mol()

M1 in the copolymer

wt() mol()

Mn SEC

copolymer

Ng Graft

32 700

83 000

][ ][ ]

[ ][ ]

[ ] [[ ] [ ]221

MrMMMr

[ ][ ] 1

[ ] [ ][ ][ ] 01

2 lnlnMM

rMM tt =

Sample M2 M1

macromer Mnth

r2 1r2

SP2 St FPP2 2000 012 plusmn 0006 833

SP15 St FPP15 1500 0042 plusmn 6 10-4 238

SP1 St FPP1 1000 0015 plusmn 3 10-4 6666

MP15 MMA FPP15 1500 007 plusmn 0 02 1428

MP1 MMA FPP1 1000 0018 plusmn 001 5555

2] t[M

ln[M1]tln[M1]0

r2 = 0015 plusmn 3 10-4 SP1

r2 = 0042 plusmn 6 10-4

2] t[M

ln[M1]tln[M1]0

r2= 012 plusmn 0006

2] t[M

ln[M1]tln[M1]0

(a) SP1 (b) SP15 (c) SP2

2] t[M

ln[M1]tln[M1]0

r2 = 0018 plusmn 001 MP1

2] t[M

ln[M1]tln[M1]0

r2 = 007 plusmn 002MP15

036788

2] t[M

ln[M1]tln[M1]0

r2 = 002 plusmn 001 MP2

(a) MP1 (b) MP15 (c) MP2

copolymers

5SP 1424 5671 1

5SP 152 5590 15

21 6739 5SP 2

303 4480 3SP 2

34 2665 2SP15

4025 2SP 4060 2

wt () (degC)

5MP 10 10545 1

5MP 13 8278 15

21 6576 3MP 2

22 7550 3MP 15

26 7013 2MP1

5 10 15 20 25 30 35 40 4520

SP COPOLYMERSTg

(degC)

10 15 20 2560

Tg (deg

MP COPOLYMERS

Conclusion

41 Background

411 Physical Blends

polymerization

Lewis acid-base etc

energy consumption

is limited

(1981)

42 Experimental

421 Materials

10 20 30 40

47 9 13 166

433 FTIR Analysis

Materials

Mw gmol

degC Tm range

degC Crystallinity

128 000

PEG Merck

35 000

60 ndash 65

a) Introduction

molecular scale203

b11 007327 minus

b22 minus 02117

b12 = (b11 b22)12 = 01245 (theo)

0 10 20 30 40

DXSP b12 003511 01295 01680 01833 01947

Δb - 00894 00050 00435 00588 00702

2SP2 b12 003511 009826 01052 01314 01515

Δb - 00894 - 00262 - 00193 00069 00270

02 03 04 05 06 07 08 09 10 11

PS PSPEG 0 PEG

C (dll)

02 03 04 05 06 07 08 09 10 1101

07BLENDS WITH DXPS

PSPEG 0 10 20 30 40 Re

ity η

C (gdl)

02 03 04 05 06 07 08 09 10 1101

08BLENDS WITH 2SP2

PSPEG 0 10 20 30 40 Re

ity η sp

C (gdl)

02 03 04 05 06 07 08 09 10 1101

PSPEG 0 2SP1 40 Re

ity η sp

C (gdl)

02 03 04 05 06 07 08 09 10 1100

DXPS 40 2SP2 40

2SP1 40

2SP1 40 2SP2 40 DXPS 40 Re

ity η

C (gdl)

copolymer

Figure 23

0 10 20 30 40 5

PS PEG BLENDS

2SP2 DXPS

in Table 14

DXPS 0 9 43 71

2SP2 0 245 109 4025

2SP1 0 40 166 30

2SP1 40

444 FTIR Analysis

associated forms

500 1000 1500 2000 2500 3000 3500 4000-05

PS and PEG PEG PS

Wave number (cm-1)

500 1000 1500 2000 2500 3000 3500 4000

0 10 20 30 40

Wave number (cm-1)

(DXPS)

of 750-1500 cm-1 and 2700- 3100 cm-1

500 1000 1500 2000 2500 3000 3500 4000

Wave number cm-1

(2SP2)

3200 3300 3400 3500 3600 3700 3800

Wave number (cm-1)

3200 3300 3400 3500 3600 3700 3800

Wave number cm-1

3200 3300 3400 3500 3600 3700 3800

DXPS 40 2SP2 40 2SP1 40

Wave number (cm-1)

References

(1969) 694ndash709

51 Introduction

52 Experimental

521 Materials

PMMAPEG

10 20 30 40

47 9 13 166

Materials

Mw gmol

degC Tm range

degC Crystallinity

55 000

PEG Merck

35 000

60 ndash 65

region in CDCl3

b11 007327 minus

b22 minus 006561

b12 = (b11 b22)12 = 006933 (theo)

0 10 20 30 40

3MP2 b12 00288 01308 01904 02373 02602

Δb - 004053 00615 01211 01680 01909

2MP2 b12 00288 01286 01690 01893 02296

Δb - 004053 00593 00997 01200 01603

3MP1 b12 00288 00868 01670 02010 02379

Δb - 004053 00175 00977 01317 01686

00 01 02 03 04 05 06 07 08 09 10 11020

040PMMAPEG (5050) 0

C (gdl)

02 03 04 05 06 07 08 09 10 11000

PMMAPEG 0 10 20 30 40 Re

C (gdl)

02 03 04 05 06 07 08 09 10 11010

045BLENDS WITH 3MP2

PMMAPEG 0 10 20 30 40

C (gdl)

02 03 04 05 06 07 08 09 10 11010

040BLENDS WITH 2MP2

PMMAPEG 0 10 20 30 40 Re

C (gdl)

0 10 20 30 40 5-01

PMMA PEG BLENDS

3MP2 2MP2 3MP1

other phase

(5050)

2MP2 0 34 16 35

3MP2 0 37 18 21

3MP1 0 58 28 19

544 FTIR Analysis

500 1000 1500 2000 2500 3000 3500 4000

20 PMMAPEG 0 Blend

Wave number cm-1

2750 2800 2850 2900 2950 3000 3050 3100-05

PEG PMMAPEG 0

Wave number cm-1

2750 2800 2850 2900 2950 3000 3050 3100

152MP2 in PMMAPEG

0 10 20 30 40

Wave number cm-1

cm-1 range

respectively)

500 1000 1500 2000 2500 3000 3500 4000

0 10 20 30 40

Wave number cm-1

500 1000 1500 2000 2500 3000 3500 4000

Wave number cm-1

500 1000 1500 2000 2500 3000 3500 4000

Wave number cm-1

3100 3150 3200 3250 3300 3350 3400 3450 3500 3550 3600 3650 3700 3750 3800

3MP1 IN PMMAPEG 40 30 20 10 0

Wave number cm-1

2MP2 40 3MP2 40 3MP1 40

Wave number cm-1

Conclusions

of the blends

CONCLUSIONS

Binder2pdf

Binder1pdf

page de gardedoc

Acknowledgementsdoc

OUTLINEdoc











SUMMARY lastdoc


CHAPTER I apresdoc





CHAPTER II 2doc

21 Introduction



CHAPTER III Apdf


CHAPTER III Baapdf

CHAPTER III Bbpdf

CHAPTER III Bcpdf

CHAPTER IV LASTpdf


References

CHAPTER Vpdf


51 Introduction

References

CONCLUSIONSpdf

SUMMARY

chapter

REacuteSUMEacute

miscibles

nous mecircme

(incompatibles)

end groups

Scheme 1

Scheme 2

method12

Scheme 3

scheme 4

Scheme 4

(ethyleneimine) (7)

Scheme 5

Scheme 6

(1988) 127-144

Protonation

Acylation

R CO SbF6 +

OR CO O SbF6

Alkylation

Et3O BF4 +

OC2H5 Et2O BF4O +

Hydrogen transfer

C SbF6 +O

C SbF6H O+

O + O O+ H O SbF6

R O++R A O

O(CH2)4

A+O(CH2)4

O (CH2)4 O+[ ]n

A O (CH2)4[ ]n

AO ( CH2 )4

CF3 SO3CH3 +O

CH3 CF3SO3O

CF3SO3

CF3SO2OSO2CF3 nO

(CH2)4 O (CH2)4 n-3

O O CF3SO3 CF3SO3

O(CH2)4

(CH2)4 O(CH2)4 OH H

++ H2O

+ LiBr

Scheme 7

macromonomer

hydroxyl groups

Scheme 8

main chain57

Scheme 9

materials6263

Scheme 10

charge buildup

homopolymer84

polymers

1 Initiation

(AIBN)

(equation 1)

polymerization

the initiation

becomes

2 Propagation

3 Termination

follows

written as

propagation

expressed as

concentration is

period of time

Therefore

shown as

reactions93

Therefore

the copolymer58

different ways

into the copolymer

η = [ r1 + r2 α ] ξ minus r2 α (50)

η = G ( α + H ) (51)

ξ = H ( α + H ) (52)

methods101 102

the form

nanostructures

materials

(2002)

dependent

Scheme 11

equation

complete

Scheme 12

References

(1985) 461

Macromonomers

21 Introduction

22 Experimental

b) Monomer

polymerization

to be about 80

under vacuum

WdWs (57)

states respectively

macromonomer

acetals54

900 cmP

-1 and 2700 to 3000 cmP

-1 and 870-800 cmP

-1 145 and are

-1 ranges

2700 cmP

-1 Below 3000 cmP

found at 1720 cmP

-1P and 1340 cmP

polymerization

FPP1 135 1000 1120 1160 16 097

FPP15 2025 1500 1540 1550 16 099

FPP2 270 2000 2040 2100 16 097

0 200 400 600 800 1000 1200 1400 16000

THF CH2Cl2

Time (min)

10-5 10-4 10-3 10-2 10-1 100 101 102101

Guns Guns Gs Gs

(hollow symbols)

frequencies

100 101

Gs Guns Gs GunsG

ω (rads)

100 101 102 103

ηlowast (P

ω (rads)

Conclusion

References

554 (2000) 99-108

31 Introduction

32 Experimental

b) Monomer

pressure

Scheme 14

Styrene (g) (mol)

AIBN (g)

THF (ml)

Conc (moll)

Scheme 16

respectively

Scheme 18

MMA (g) (mol)

AIBN (g)

THF (ml)

Conc (moll)

2MP15 FPP15 20 2 133 10-4 28 280 10-2 005 25 100 3MP15 FPP15 30 187 125 10-4 3744 374 0-2

006 60 0644 5MP15 FPP15 50 112 748 10-4 3744 374 10-2 005 60 0636

2MP1 FPP1 20 2 20 10-4 400 4 10-2

006 50 0840 3MP1 FPP1 50 125 125 10-4 3744 374 10-2 005 64 0604 5MP1 FPP1 80 075 748 10-4 3744 374 10-2 005 60 0636

chains

Sample

M1 in the feed

wt() mol()

M1 in the copolymer

wt() mol()

Mn SEC

Sample

M1 in the feed

wt() mol()

M1 in the copolymer

wt() mol()

Mn SEC

copolymer

Ng Graft

32 700

83 000

][ ][ ]

[ ][ ]

[ ] [[ ] [ ]221

MrMMMr

[ ][ ] 1

[ ] [ ][ ][ ] 01

2 lnlnMM

rMM tt =

Sample M2 M1

macromer Mnth

r2 1r2

SP2 St FPP2 2000 012 plusmn 0006 833

SP15 St FPP15 1500 0042 plusmn 6 10-4 238

SP1 St FPP1 1000 0015 plusmn 3 10-4 6666

MP15 MMA FPP15 1500 007 plusmn 0 02 1428

MP1 MMA FPP1 1000 0018 plusmn 001 5555

2] t[M

ln[M1]tln[M1]0

r2 = 0015 plusmn 3 10-4 SP1

r2 = 0042 plusmn 6 10-4

2] t[M

ln[M1]tln[M1]0

r2= 012 plusmn 0006

2] t[M

ln[M1]tln[M1]0

(a) SP1 (b) SP15 (c) SP2

2] t[M

ln[M1]tln[M1]0

r2 = 0018 plusmn 001 MP1

2] t[M

ln[M1]tln[M1]0

r2 = 007 plusmn 002MP15

036788

2] t[M

ln[M1]tln[M1]0

r2 = 002 plusmn 001 MP2

(a) MP1 (b) MP15 (c) MP2

copolymers

5SP 1424 5671 1

5SP 152 5590 15

21 6739 5SP 2

303 4480 3SP 2

34 2665 2SP15

4025 2SP 4060 2

wt () (degC)

5MP 10 10545 1

5MP 13 8278 15

21 6576 3MP 2

22 7550 3MP 15

26 7013 2MP1

5 10 15 20 25 30 35 40 4520

SP COPOLYMERSTg

(degC)

10 15 20 2560

Tg (deg

MP COPOLYMERS

Conclusion

41 Background

411 Physical Blends

polymerization

Lewis acid-base etc

energy consumption

is limited

(1981)

42 Experimental

421 Materials

10 20 30 40

47 9 13 166

433 FTIR Analysis

Materials

Mw gmol

degC Tm range

degC Crystallinity

128 000

PEG Merck

35 000

60 ndash 65

a) Introduction

molecular scale203

b11 007327 minus

b22 minus 02117

b12 = (b11 b22)12 = 01245 (theo)

0 10 20 30 40

DXSP b12 003511 01295 01680 01833 01947

Δb - 00894 00050 00435 00588 00702

2SP2 b12 003511 009826 01052 01314 01515

Δb - 00894 - 00262 - 00193 00069 00270

02 03 04 05 06 07 08 09 10 11

PS PSPEG 0 PEG

C (dll)

02 03 04 05 06 07 08 09 10 1101

07BLENDS WITH DXPS

PSPEG 0 10 20 30 40 Re

ity η

C (gdl)

02 03 04 05 06 07 08 09 10 1101

08BLENDS WITH 2SP2

PSPEG 0 10 20 30 40 Re

ity η sp

C (gdl)

02 03 04 05 06 07 08 09 10 1101

PSPEG 0 2SP1 40 Re

ity η sp

C (gdl)

02 03 04 05 06 07 08 09 10 1100

DXPS 40 2SP2 40

2SP1 40

2SP1 40 2SP2 40 DXPS 40 Re

ity η

C (gdl)

copolymer

Figure 23

0 10 20 30 40 5

PS PEG BLENDS

2SP2 DXPS

in Table 14

DXPS 0 9 43 71

2SP2 0 245 109 4025

2SP1 0 40 166 30

2SP1 40

444 FTIR Analysis

associated forms

500 1000 1500 2000 2500 3000 3500 4000-05

PS and PEG PEG PS

Wave number (cm-1)

500 1000 1500 2000 2500 3000 3500 4000

0 10 20 30 40

Wave number (cm-1)

(DXPS)

of 750-1500 cm-1 and 2700- 3100 cm-1

500 1000 1500 2000 2500 3000 3500 4000

Wave number cm-1

(2SP2)

3200 3300 3400 3500 3600 3700 3800

Wave number (cm-1)

3200 3300 3400 3500 3600 3700 3800

Wave number cm-1

3200 3300 3400 3500 3600 3700 3800

DXPS 40 2SP2 40 2SP1 40

Wave number (cm-1)

References

(1969) 694ndash709

51 Introduction

52 Experimental

521 Materials

PMMAPEG

10 20 30 40

47 9 13 166

Materials

Mw gmol

degC Tm range

degC Crystallinity

55 000

PEG Merck

35 000

60 ndash 65

region in CDCl3

b11 007327 minus

b22 minus 006561

b12 = (b11 b22)12 = 006933 (theo)

0 10 20 30 40

3MP2 b12 00288 01308 01904 02373 02602

Δb - 004053 00615 01211 01680 01909

2MP2 b12 00288 01286 01690 01893 02296

Δb - 004053 00593 00997 01200 01603

3MP1 b12 00288 00868 01670 02010 02379

Δb - 004053 00175 00977 01317 01686

00 01 02 03 04 05 06 07 08 09 10 11020

040PMMAPEG (5050) 0

C (gdl)

02 03 04 05 06 07 08 09 10 11000

PMMAPEG 0 10 20 30 40 Re

C (gdl)

02 03 04 05 06 07 08 09 10 11010

045BLENDS WITH 3MP2

PMMAPEG 0 10 20 30 40

C (gdl)

02 03 04 05 06 07 08 09 10 11010

040BLENDS WITH 2MP2

PMMAPEG 0 10 20 30 40 Re

C (gdl)

0 10 20 30 40 5-01

PMMA PEG BLENDS

3MP2 2MP2 3MP1

other phase

(5050)

2MP2 0 34 16 35

3MP2 0 37 18 21

3MP1 0 58 28 19

544 FTIR Analysis

500 1000 1500 2000 2500 3000 3500 4000

20 PMMAPEG 0 Blend

Wave number cm-1

2750 2800 2850 2900 2950 3000 3050 3100-05

PEG PMMAPEG 0

Wave number cm-1

2750 2800 2850 2900 2950 3000 3050 3100

152MP2 in PMMAPEG

0 10 20 30 40

Wave number cm-1

cm-1 range

respectively)

500 1000 1500 2000 2500 3000 3500 4000

0 10 20 30 40

Wave number cm-1

500 1000 1500 2000 2500 3000 3500 4000

Wave number cm-1

500 1000 1500 2000 2500 3000 3500 4000

Wave number cm-1

3100 3150 3200 3250 3300 3350 3400 3450 3500 3550 3600 3650 3700 3750 3800

3MP1 IN PMMAPEG 40 30 20 10 0

Wave number cm-1

2MP2 40 3MP2 40 3MP1 40

Wave number cm-1

Conclusions

of the blends

CONCLUSIONS

Binder2pdf

Binder1pdf

page de gardedoc

Acknowledgementsdoc

OUTLINEdoc











SUMMARY lastdoc


CHAPTER I apresdoc





CHAPTER II 2doc

21 Introduction



CHAPTER III Apdf


CHAPTER III Baapdf

CHAPTER III Bbpdf

CHAPTER III Bcpdf

CHAPTER IV LASTpdf


References

CHAPTER Vpdf


51 Introduction

References

CONCLUSIONSpdf

SUMMARY

chapter

REacuteSUMEacute

miscibles

nous mecircme

(incompatibles)

end groups

Scheme 1

Scheme 2

method12

Scheme 3

scheme 4

Scheme 4

(ethyleneimine) (7)

Scheme 5

Scheme 6

(1988) 127-144

Protonation

Acylation

R CO SbF6 +

OR CO O SbF6

Alkylation

Et3O BF4 +

OC2H5 Et2O BF4O +

Hydrogen transfer

C SbF6 +O

C SbF6H O+

O + O O+ H O SbF6

R O++R A O

O(CH2)4

A+O(CH2)4

O (CH2)4 O+[ ]n

A O (CH2)4[ ]n

AO ( CH2 )4

CF3 SO3CH3 +O

CH3 CF3SO3O

CF3SO3

CF3SO2OSO2CF3 nO

(CH2)4 O (CH2)4 n-3

O O CF3SO3 CF3SO3

O(CH2)4

(CH2)4 O(CH2)4 OH H

++ H2O

+ LiBr

Scheme 7

macromonomer

hydroxyl groups

Scheme 8

main chain57

Scheme 9

materials6263

Scheme 10

charge buildup

homopolymer84

polymers

1 Initiation

(AIBN)

(equation 1)

polymerization

the initiation

becomes

2 Propagation

3 Termination

follows

written as

propagation

expressed as

concentration is

period of time

Therefore

shown as

reactions93

Therefore

the copolymer58

different ways

into the copolymer

η = [ r1 + r2 α ] ξ minus r2 α (50)

η = G ( α + H ) (51)

ξ = H ( α + H ) (52)

methods101 102

the form

nanostructures

materials

(2002)

dependent

Scheme 11

equation

complete

Scheme 12

References

(1985) 461

Macromonomers

21 Introduction

22 Experimental

b) Monomer

polymerization

to be about 80

under vacuum

WdWs (57)

states respectively

macromonomer

acetals54

900 cmP

-1 and 2700 to 3000 cmP

-1 and 870-800 cmP

-1 145 and are

-1 ranges

2700 cmP

-1 Below 3000 cmP

found at 1720 cmP

-1P and 1340 cmP

polymerization

FPP1 135 1000 1120 1160 16 097

FPP15 2025 1500 1540 1550 16 099

FPP2 270 2000 2040 2100 16 097

0 200 400 600 800 1000 1200 1400 16000

THF CH2Cl2

Time (min)

10-5 10-4 10-3 10-2 10-1 100 101 102101

Guns Guns Gs Gs

(hollow symbols)

frequencies

100 101

Gs Guns Gs GunsG

ω (rads)

100 101 102 103

ηlowast (P

ω (rads)

Conclusion

References

554 (2000) 99-108

31 Introduction

32 Experimental

b) Monomer

pressure

Scheme 14

Styrene (g) (mol)

AIBN (g)

THF (ml)

Conc (moll)

Scheme 16

respectively

Scheme 18

MMA (g) (mol)

AIBN (g)

THF (ml)

Conc (moll)

2MP15 FPP15 20 2 133 10-4 28 280 10-2 005 25 100 3MP15 FPP15 30 187 125 10-4 3744 374 0-2

006 60 0644 5MP15 FPP15 50 112 748 10-4 3744 374 10-2 005 60 0636

2MP1 FPP1 20 2 20 10-4 400 4 10-2

006 50 0840 3MP1 FPP1 50 125 125 10-4 3744 374 10-2 005 64 0604 5MP1 FPP1 80 075 748 10-4 3744 374 10-2 005 60 0636

chains

Sample

M1 in the feed

wt() mol()

M1 in the copolymer

wt() mol()

Mn SEC

Sample

M1 in the feed

wt() mol()

M1 in the copolymer

wt() mol()

Mn SEC

copolymer

Ng Graft

32 700

83 000

][ ][ ]

[ ][ ]

[ ] [[ ] [ ]221

MrMMMr

[ ][ ] 1

[ ] [ ][ ][ ] 01

2 lnlnMM

rMM tt =

Sample M2 M1

macromer Mnth

r2 1r2

SP2 St FPP2 2000 012 plusmn 0006 833

SP15 St FPP15 1500 0042 plusmn 6 10-4 238

SP1 St FPP1 1000 0015 plusmn 3 10-4 6666

MP15 MMA FPP15 1500 007 plusmn 0 02 1428

MP1 MMA FPP1 1000 0018 plusmn 001 5555

2] t[M

ln[M1]tln[M1]0

r2 = 0015 plusmn 3 10-4 SP1

r2 = 0042 plusmn 6 10-4

2] t[M

ln[M1]tln[M1]0

r2= 012 plusmn 0006

2] t[M

ln[M1]tln[M1]0

(a) SP1 (b) SP15 (c) SP2

2] t[M

ln[M1]tln[M1]0

r2 = 0018 plusmn 001 MP1

2] t[M

ln[M1]tln[M1]0

r2 = 007 plusmn 002MP15

036788

2] t[M

ln[M1]tln[M1]0

r2 = 002 plusmn 001 MP2

(a) MP1 (b) MP15 (c) MP2

copolymers

5SP 1424 5671 1

5SP 152 5590 15

21 6739 5SP 2

303 4480 3SP 2

34 2665 2SP15

4025 2SP 4060 2

wt () (degC)

5MP 10 10545 1

5MP 13 8278 15

21 6576 3MP 2

22 7550 3MP 15

26 7013 2MP1

5 10 15 20 25 30 35 40 4520

SP COPOLYMERSTg

(degC)

10 15 20 2560

Tg (deg

MP COPOLYMERS

Conclusion

41 Background

411 Physical Blends

polymerization

Lewis acid-base etc

energy consumption

is limited

(1981)

42 Experimental

421 Materials

10 20 30 40

47 9 13 166

433 FTIR Analysis

Materials

Mw gmol

degC Tm range

degC Crystallinity

128 000

PEG Merck

35 000

60 ndash 65

a) Introduction

molecular scale203

b11 007327 minus

b22 minus 02117

b12 = (b11 b22)12 = 01245 (theo)

0 10 20 30 40

DXSP b12 003511 01295 01680 01833 01947

Δb - 00894 00050 00435 00588 00702

2SP2 b12 003511 009826 01052 01314 01515

Δb - 00894 - 00262 - 00193 00069 00270

02 03 04 05 06 07 08 09 10 11

PS PSPEG 0 PEG

C (dll)

02 03 04 05 06 07 08 09 10 1101

07BLENDS WITH DXPS

PSPEG 0 10 20 30 40 Re

ity η

C (gdl)

02 03 04 05 06 07 08 09 10 1101

08BLENDS WITH 2SP2

PSPEG 0 10 20 30 40 Re

ity η sp

C (gdl)

02 03 04 05 06 07 08 09 10 1101

PSPEG 0 2SP1 40 Re

ity η sp

C (gdl)

02 03 04 05 06 07 08 09 10 1100

DXPS 40 2SP2 40

2SP1 40

2SP1 40 2SP2 40 DXPS 40 Re

ity η

C (gdl)

copolymer

Figure 23

0 10 20 30 40 5

PS PEG BLENDS

2SP2 DXPS

in Table 14

DXPS 0 9 43 71

2SP2 0 245 109 4025

2SP1 0 40 166 30

2SP1 40

444 FTIR Analysis

associated forms

500 1000 1500 2000 2500 3000 3500 4000-05

PS and PEG PEG PS

Wave number (cm-1)

500 1000 1500 2000 2500 3000 3500 4000

0 10 20 30 40

Wave number (cm-1)

(DXPS)

of 750-1500 cm-1 and 2700- 3100 cm-1

500 1000 1500 2000 2500 3000 3500 4000

Wave number cm-1

(2SP2)

3200 3300 3400 3500 3600 3700 3800

Wave number (cm-1)

3200 3300 3400 3500 3600 3700 3800

Wave number cm-1

3200 3300 3400 3500 3600 3700 3800

DXPS 40 2SP2 40 2SP1 40

Wave number (cm-1)

References

(1969) 694ndash709

51 Introduction

52 Experimental

521 Materials

PMMAPEG

10 20 30 40

47 9 13 166

Materials

Mw gmol

degC Tm range

degC Crystallinity

55 000

PEG Merck

35 000

60 ndash 65

region in CDCl3

b11 007327 minus

b22 minus 006561

b12 = (b11 b22)12 = 006933 (theo)

0 10 20 30 40

3MP2 b12 00288 01308 01904 02373 02602

Δb - 004053 00615 01211 01680 01909

2MP2 b12 00288 01286 01690 01893 02296

Δb - 004053 00593 00997 01200 01603

3MP1 b12 00288 00868 01670 02010 02379

Δb - 004053 00175 00977 01317 01686

00 01 02 03 04 05 06 07 08 09 10 11020

040PMMAPEG (5050) 0

C (gdl)

02 03 04 05 06 07 08 09 10 11000

PMMAPEG 0 10 20 30 40 Re

C (gdl)

02 03 04 05 06 07 08 09 10 11010

045BLENDS WITH 3MP2

PMMAPEG 0 10 20 30 40

C (gdl)

02 03 04 05 06 07 08 09 10 11010

040BLENDS WITH 2MP2

PMMAPEG 0 10 20 30 40 Re

C (gdl)

0 10 20 30 40 5-01

PMMA PEG BLENDS

3MP2 2MP2 3MP1

other phase

(5050)

2MP2 0 34 16 35

3MP2 0 37 18 21

3MP1 0 58 28 19

544 FTIR Analysis

500 1000 1500 2000 2500 3000 3500 4000

20 PMMAPEG 0 Blend

Wave number cm-1

2750 2800 2850 2900 2950 3000 3050 3100-05

PEG PMMAPEG 0

Wave number cm-1

2750 2800 2850 2900 2950 3000 3050 3100

152MP2 in PMMAPEG

0 10 20 30 40

Wave number cm-1

cm-1 range

respectively)

500 1000 1500 2000 2500 3000 3500 4000

0 10 20 30 40

Wave number cm-1

500 1000 1500 2000 2500 3000 3500 4000

Wave number cm-1

500 1000 1500 2000 2500 3000 3500 4000

Wave number cm-1

3100 3150 3200 3250 3300 3350 3400 3450 3500 3550 3600 3650 3700 3750 3800

3MP1 IN PMMAPEG 40 30 20 10 0

Wave number cm-1

2MP2 40 3MP2 40 3MP1 40

Wave number cm-1

Conclusions

of the blends

CONCLUSIONS

Binder2pdf

Binder1pdf

page de gardedoc

Acknowledgementsdoc

OUTLINEdoc











SUMMARY lastdoc


CHAPTER I apresdoc





CHAPTER II 2doc

21 Introduction



CHAPTER III Apdf


CHAPTER III Baapdf

CHAPTER III Bbpdf

CHAPTER III Bcpdf

CHAPTER IV LASTpdf


References

CHAPTER Vpdf


51 Introduction

References

CONCLUSIONSpdf

SUMMARY

chapter

REacuteSUMEacute

miscibles

nous mecircme

(incompatibles)

end groups

Scheme 1

Scheme 2

method12

Scheme 3

scheme 4

Scheme 4

(ethyleneimine) (7)

Scheme 5

Scheme 6

(1988) 127-144

Protonation

Acylation

R CO SbF6 +

OR CO O SbF6

Alkylation

Et3O BF4 +

OC2H5 Et2O BF4O +

Hydrogen transfer

C SbF6 +O

C SbF6H O+

O + O O+ H O SbF6

R O++R A O

O(CH2)4

A+O(CH2)4

O (CH2)4 O+[ ]n

A O (CH2)4[ ]n

AO ( CH2 )4

CF3 SO3CH3 +O

CH3 CF3SO3O

CF3SO3

CF3SO2OSO2CF3 nO

(CH2)4 O (CH2)4 n-3

O O CF3SO3 CF3SO3

O(CH2)4

(CH2)4 O(CH2)4 OH H

++ H2O

+ LiBr

Scheme 7

macromonomer

hydroxyl groups

Scheme 8

main chain57

Scheme 9

materials6263

Scheme 10

charge buildup

homopolymer84

polymers

1 Initiation

(AIBN)

(equation 1)

polymerization

the initiation

becomes

2 Propagation

3 Termination

follows

written as

propagation

expressed as

concentration is

period of time

Therefore

shown as

reactions93

Therefore

the copolymer58

different ways

into the copolymer

η = [ r1 + r2 α ] ξ minus r2 α (50)

η = G ( α + H ) (51)

ξ = H ( α + H ) (52)

methods101 102

the form

nanostructures

materials

(2002)

dependent

Scheme 11

equation

complete

Scheme 12

References

(1985) 461

Macromonomers

21 Introduction

22 Experimental

b) Monomer

polymerization

to be about 80

under vacuum

WdWs (57)

states respectively

macromonomer

acetals54

900 cmP

-1 and 2700 to 3000 cmP

-1 and 870-800 cmP

-1 145 and are

-1 ranges

2700 cmP

-1 Below 3000 cmP

found at 1720 cmP

-1P and 1340 cmP

polymerization

FPP1 135 1000 1120 1160 16 097

FPP15 2025 1500 1540 1550 16 099

FPP2 270 2000 2040 2100 16 097

0 200 400 600 800 1000 1200 1400 16000

THF CH2Cl2

Time (min)

10-5 10-4 10-3 10-2 10-1 100 101 102101

Guns Guns Gs Gs

(hollow symbols)

frequencies

100 101

Gs Guns Gs GunsG

ω (rads)

100 101 102 103

ηlowast (P

ω (rads)

Conclusion

References

554 (2000) 99-108

31 Introduction

32 Experimental

b) Monomer

pressure

Scheme 14

Styrene (g) (mol)

AIBN (g)

THF (ml)

Conc (moll)

Scheme 16

respectively

Scheme 18

MMA (g) (mol)

AIBN (g)

THF (ml)

Conc (moll)

2MP15 FPP15 20 2 133 10-4 28 280 10-2 005 25 100 3MP15 FPP15 30 187 125 10-4 3744 374 0-2

006 60 0644 5MP15 FPP15 50 112 748 10-4 3744 374 10-2 005 60 0636

2MP1 FPP1 20 2 20 10-4 400 4 10-2

006 50 0840 3MP1 FPP1 50 125 125 10-4 3744 374 10-2 005 64 0604 5MP1 FPP1 80 075 748 10-4 3744 374 10-2 005 60 0636

chains

Sample

M1 in the feed

wt() mol()

M1 in the copolymer

wt() mol()

Mn SEC

Sample

M1 in the feed

wt() mol()

M1 in the copolymer

wt() mol()

Mn SEC

copolymer

Ng Graft

32 700

83 000

][ ][ ]

[ ][ ]

[ ] [[ ] [ ]221

MrMMMr

[ ][ ] 1

[ ] [ ][ ][ ] 01

2 lnlnMM

rMM tt =

Sample M2 M1

macromer Mnth

r2 1r2

SP2 St FPP2 2000 012 plusmn 0006 833

SP15 St FPP15 1500 0042 plusmn 6 10-4 238

SP1 St FPP1 1000 0015 plusmn 3 10-4 6666

MP15 MMA FPP15 1500 007 plusmn 0 02 1428

MP1 MMA FPP1 1000 0018 plusmn 001 5555

2] t[M

ln[M1]tln[M1]0

r2 = 0015 plusmn 3 10-4 SP1

r2 = 0042 plusmn 6 10-4

2] t[M

ln[M1]tln[M1]0

r2= 012 plusmn 0006

2] t[M

ln[M1]tln[M1]0

(a) SP1 (b) SP15 (c) SP2

2] t[M

ln[M1]tln[M1]0

r2 = 0018 plusmn 001 MP1

2] t[M

ln[M1]tln[M1]0

r2 = 007 plusmn 002MP15

036788

2] t[M

ln[M1]tln[M1]0

r2 = 002 plusmn 001 MP2

(a) MP1 (b) MP15 (c) MP2

copolymers

5SP 1424 5671 1

5SP 152 5590 15

21 6739 5SP 2

303 4480 3SP 2

34 2665 2SP15

4025 2SP 4060 2

wt () (degC)

5MP 10 10545 1

5MP 13 8278 15

21 6576 3MP 2

22 7550 3MP 15

26 7013 2MP1

5 10 15 20 25 30 35 40 4520

SP COPOLYMERSTg

(degC)

10 15 20 2560

Tg (deg

MP COPOLYMERS

Conclusion

41 Background

411 Physical Blends

polymerization

Lewis acid-base etc

energy consumption

is limited

(1981)

42 Experimental

421 Materials

10 20 30 40

47 9 13 166

433 FTIR Analysis

Materials

Mw gmol

degC Tm range

degC Crystallinity

128 000

PEG Merck

35 000

60 ndash 65

a) Introduction

molecular scale203

b11 007327 minus

b22 minus 02117

b12 = (b11 b22)12 = 01245 (theo)

0 10 20 30 40

DXSP b12 003511 01295 01680 01833 01947

Δb - 00894 00050 00435 00588 00702

2SP2 b12 003511 009826 01052 01314 01515

Δb - 00894 - 00262 - 00193 00069 00270

02 03 04 05 06 07 08 09 10 11

PS PSPEG 0 PEG

C (dll)

02 03 04 05 06 07 08 09 10 1101

07BLENDS WITH DXPS

PSPEG 0 10 20 30 40 Re

ity η

C (gdl)

02 03 04 05 06 07 08 09 10 1101

08BLENDS WITH 2SP2

PSPEG 0 10 20 30 40 Re

ity η sp

C (gdl)

02 03 04 05 06 07 08 09 10 1101

PSPEG 0 2SP1 40 Re

ity η sp

C (gdl)

02 03 04 05 06 07 08 09 10 1100

DXPS 40 2SP2 40

2SP1 40

2SP1 40 2SP2 40 DXPS 40 Re

ity η

C (gdl)

copolymer

Figure 23

0 10 20 30 40 5

PS PEG BLENDS

2SP2 DXPS

in Table 14

DXPS 0 9 43 71

2SP2 0 245 109 4025

2SP1 0 40 166 30

2SP1 40

444 FTIR Analysis

associated forms

500 1000 1500 2000 2500 3000 3500 4000-05

PS and PEG PEG PS

Wave number (cm-1)

500 1000 1500 2000 2500 3000 3500 4000

0 10 20 30 40

Wave number (cm-1)

(DXPS)

of 750-1500 cm-1 and 2700- 3100 cm-1

500 1000 1500 2000 2500 3000 3500 4000

Wave number cm-1

(2SP2)

3200 3300 3400 3500 3600 3700 3800

Wave number (cm-1)

3200 3300 3400 3500 3600 3700 3800

Wave number cm-1

3200 3300 3400 3500 3600 3700 3800

DXPS 40 2SP2 40 2SP1 40

Wave number (cm-1)

References

(1969) 694ndash709

51 Introduction

52 Experimental

521 Materials

PMMAPEG

10 20 30 40

47 9 13 166

Materials

Mw gmol

degC Tm range

degC Crystallinity

55 000

PEG Merck

35 000

60 ndash 65

region in CDCl3

b11 007327 minus

b22 minus 006561

b12 = (b11 b22)12 = 006933 (theo)

0 10 20 30 40

3MP2 b12 00288 01308 01904 02373 02602

Δb - 004053 00615 01211 01680 01909

2MP2 b12 00288 01286 01690 01893 02296

Δb - 004053 00593 00997 01200 01603

3MP1 b12 00288 00868 01670 02010 02379

Δb - 004053 00175 00977 01317 01686

00 01 02 03 04 05 06 07 08 09 10 11020

040PMMAPEG (5050) 0

C (gdl)

02 03 04 05 06 07 08 09 10 11000

PMMAPEG 0 10 20 30 40 Re

C (gdl)

02 03 04 05 06 07 08 09 10 11010

045BLENDS WITH 3MP2

PMMAPEG 0 10 20 30 40

C (gdl)

02 03 04 05 06 07 08 09 10 11010

040BLENDS WITH 2MP2

PMMAPEG 0 10 20 30 40 Re

C (gdl)

0 10 20 30 40 5-01

PMMA PEG BLENDS

3MP2 2MP2 3MP1

other phase

(5050)

2MP2 0 34 16 35

3MP2 0 37 18 21

3MP1 0 58 28 19

544 FTIR Analysis

500 1000 1500 2000 2500 3000 3500 4000

20 PMMAPEG 0 Blend

Wave number cm-1

2750 2800 2850 2900 2950 3000 3050 3100-05

PEG PMMAPEG 0

Wave number cm-1

2750 2800 2850 2900 2950 3000 3050 3100

152MP2 in PMMAPEG

0 10 20 30 40

Wave number cm-1

cm-1 range

respectively)

500 1000 1500 2000 2500 3000 3500 4000

0 10 20 30 40

Wave number cm-1

500 1000 1500 2000 2500 3000 3500 4000

Wave number cm-1

500 1000 1500 2000 2500 3000 3500 4000

Wave number cm-1

3100 3150 3200 3250 3300 3350 3400 3450 3500 3550 3600 3650 3700 3750 3800

3MP1 IN PMMAPEG 40 30 20 10 0

Wave number cm-1

2MP2 40 3MP2 40 3MP1 40

Wave number cm-1

Conclusions

of the blends

CONCLUSIONS

Binder2pdf

Binder1pdf

page de gardedoc

Acknowledgementsdoc

OUTLINEdoc











SUMMARY lastdoc


CHAPTER I apresdoc





CHAPTER II 2doc

21 Introduction



CHAPTER III Apdf


CHAPTER III Baapdf

CHAPTER III Bbpdf

CHAPTER III Bcpdf

CHAPTER IV LASTpdf


References

CHAPTER Vpdf


51 Introduction

References

CONCLUSIONSpdf

SUMMARY

chapter

REacuteSUMEacute

miscibles

nous mecircme

(incompatibles)

end groups

Scheme 1

Scheme 2

method12

Scheme 3

scheme 4

Scheme 4

(ethyleneimine) (7)

Scheme 5

Scheme 6

(1988) 127-144

Protonation

Acylation

R CO SbF6 +

OR CO O SbF6

Alkylation

Et3O BF4 +

OC2H5 Et2O BF4O +

Hydrogen transfer

C SbF6 +O

C SbF6H O+

O + O O+ H O SbF6

R O++R A O

O(CH2)4

A+O(CH2)4

O (CH2)4 O+[ ]n

A O (CH2)4[ ]n

AO ( CH2 )4

CF3 SO3CH3 +O

CH3 CF3SO3O

CF3SO3

CF3SO2OSO2CF3 nO

(CH2)4 O (CH2)4 n-3

O O CF3SO3 CF3SO3

O(CH2)4

(CH2)4 O(CH2)4 OH H

++ H2O

+ LiBr

Scheme 7

macromonomer

hydroxyl groups

Scheme 8

main chain57

Scheme 9

materials6263

Scheme 10

charge buildup

homopolymer84

polymers

1 Initiation

(AIBN)

(equation 1)

polymerization

the initiation

becomes

2 Propagation

3 Termination

follows

written as

propagation

expressed as

concentration is

period of time

Therefore

shown as

reactions93

Therefore

the copolymer58

different ways

into the copolymer

η = [ r1 + r2 α ] ξ minus r2 α (50)

η = G ( α + H ) (51)

ξ = H ( α + H ) (52)

methods101 102

the form

nanostructures

materials

(2002)

dependent

Scheme 11

equation

complete

Scheme 12

References

(1985) 461

Macromonomers

21 Introduction

22 Experimental

b) Monomer

polymerization

to be about 80

under vacuum

WdWs (57)

states respectively

macromonomer

acetals54

900 cmP

-1 and 2700 to 3000 cmP

-1 and 870-800 cmP

-1 145 and are

-1 ranges

2700 cmP

-1 Below 3000 cmP

found at 1720 cmP

-1P and 1340 cmP

polymerization

FPP1 135 1000 1120 1160 16 097

FPP15 2025 1500 1540 1550 16 099

FPP2 270 2000 2040 2100 16 097

0 200 400 600 800 1000 1200 1400 16000

THF CH2Cl2

Time (min)

10-5 10-4 10-3 10-2 10-1 100 101 102101

Guns Guns Gs Gs

(hollow symbols)

frequencies

100 101

Gs Guns Gs GunsG

ω (rads)

100 101 102 103

ηlowast (P

ω (rads)

Conclusion

References

554 (2000) 99-108

31 Introduction

32 Experimental

b) Monomer

pressure

Scheme 14

Styrene (g) (mol)

AIBN (g)

THF (ml)

Conc (moll)

Scheme 16

respectively

Scheme 18

MMA (g) (mol)

AIBN (g)

THF (ml)

Conc (moll)

2MP15 FPP15 20 2 133 10-4 28 280 10-2 005 25 100 3MP15 FPP15 30 187 125 10-4 3744 374 0-2

006 60 0644 5MP15 FPP15 50 112 748 10-4 3744 374 10-2 005 60 0636

2MP1 FPP1 20 2 20 10-4 400 4 10-2

006 50 0840 3MP1 FPP1 50 125 125 10-4 3744 374 10-2 005 64 0604 5MP1 FPP1 80 075 748 10-4 3744 374 10-2 005 60 0636

chains

Sample

M1 in the feed

wt() mol()

M1 in the copolymer

wt() mol()

Mn SEC

Sample

M1 in the feed

wt() mol()

M1 in the copolymer

wt() mol()

Mn SEC

copolymer

Ng Graft

32 700

83 000

][ ][ ]

[ ][ ]

[ ] [[ ] [ ]221

MrMMMr

[ ][ ] 1

[ ] [ ][ ][ ] 01

2 lnlnMM

rMM tt =

Sample M2 M1

macromer Mnth

r2 1r2

SP2 St FPP2 2000 012 plusmn 0006 833

SP15 St FPP15 1500 0042 plusmn 6 10-4 238

SP1 St FPP1 1000 0015 plusmn 3 10-4 6666

MP15 MMA FPP15 1500 007 plusmn 0 02 1428

MP1 MMA FPP1 1000 0018 plusmn 001 5555

2] t[M

ln[M1]tln[M1]0

r2 = 0015 plusmn 3 10-4 SP1

r2 = 0042 plusmn 6 10-4

2] t[M

ln[M1]tln[M1]0

r2= 012 plusmn 0006

2] t[M

ln[M1]tln[M1]0

(a) SP1 (b) SP15 (c) SP2

2] t[M

ln[M1]tln[M1]0

r2 = 0018 plusmn 001 MP1

2] t[M

ln[M1]tln[M1]0

r2 = 007 plusmn 002MP15

036788

2] t[M

ln[M1]tln[M1]0

r2 = 002 plusmn 001 MP2

(a) MP1 (b) MP15 (c) MP2

copolymers

5SP 1424 5671 1

5SP 152 5590 15

21 6739 5SP 2

303 4480 3SP 2

34 2665 2SP15

4025 2SP 4060 2

wt () (degC)

5MP 10 10545 1

5MP 13 8278 15

21 6576 3MP 2

22 7550 3MP 15

26 7013 2MP1

5 10 15 20 25 30 35 40 4520

SP COPOLYMERSTg

(degC)

10 15 20 2560

Tg (deg

MP COPOLYMERS

Conclusion

41 Background

411 Physical Blends

polymerization

Lewis acid-base etc

energy consumption

is limited

(1981)

42 Experimental

421 Materials

10 20 30 40

47 9 13 166

433 FTIR Analysis

Materials

Mw gmol

degC Tm range

degC Crystallinity

128 000

PEG Merck

35 000

60 ndash 65

a) Introduction

molecular scale203

b11 007327 minus

b22 minus 02117

b12 = (b11 b22)12 = 01245 (theo)

0 10 20 30 40

DXSP b12 003511 01295 01680 01833 01947

Δb - 00894 00050 00435 00588 00702

2SP2 b12 003511 009826 01052 01314 01515

Δb - 00894 - 00262 - 00193 00069 00270

02 03 04 05 06 07 08 09 10 11

PS PSPEG 0 PEG

C (dll)

02 03 04 05 06 07 08 09 10 1101

07BLENDS WITH DXPS

PSPEG 0 10 20 30 40 Re

ity η

C (gdl)

02 03 04 05 06 07 08 09 10 1101

08BLENDS WITH 2SP2

PSPEG 0 10 20 30 40 Re

ity η sp

C (gdl)

02 03 04 05 06 07 08 09 10 1101

PSPEG 0 2SP1 40 Re

ity η sp

C (gdl)

02 03 04 05 06 07 08 09 10 1100

DXPS 40 2SP2 40

2SP1 40

2SP1 40 2SP2 40 DXPS 40 Re

ity η

C (gdl)

copolymer

Figure 23

0 10 20 30 40 5

PS PEG BLENDS

2SP2 DXPS

in Table 14

DXPS 0 9 43 71

2SP2 0 245 109 4025

2SP1 0 40 166 30

2SP1 40

444 FTIR Analysis

associated forms

500 1000 1500 2000 2500 3000 3500 4000-05

PS and PEG PEG PS

Wave number (cm-1)

500 1000 1500 2000 2500 3000 3500 4000

0 10 20 30 40

Wave number (cm-1)

(DXPS)

of 750-1500 cm-1 and 2700- 3100 cm-1

500 1000 1500 2000 2500 3000 3500 4000

Wave number cm-1

(2SP2)

3200 3300 3400 3500 3600 3700 3800

Wave number (cm-1)

3200 3300 3400 3500 3600 3700 3800

Wave number cm-1

3200 3300 3400 3500 3600 3700 3800

DXPS 40 2SP2 40 2SP1 40

Wave number (cm-1)

References

(1969) 694ndash709

51 Introduction

52 Experimental

521 Materials

PMMAPEG

10 20 30 40

47 9 13 166

Materials

Mw gmol

degC Tm range

degC Crystallinity

55 000

PEG Merck

35 000

60 ndash 65

region in CDCl3

b11 007327 minus

b22 minus 006561

b12 = (b11 b22)12 = 006933 (theo)

0 10 20 30 40

3MP2 b12 00288 01308 01904 02373 02602

Δb - 004053 00615 01211 01680 01909

2MP2 b12 00288 01286 01690 01893 02296

Δb - 004053 00593 00997 01200 01603

3MP1 b12 00288 00868 01670 02010 02379

Δb - 004053 00175 00977 01317 01686

00 01 02 03 04 05 06 07 08 09 10 11020

040PMMAPEG (5050) 0

C (gdl)

02 03 04 05 06 07 08 09 10 11000

PMMAPEG 0 10 20 30 40 Re

C (gdl)

02 03 04 05 06 07 08 09 10 11010

045BLENDS WITH 3MP2

PMMAPEG 0 10 20 30 40

C (gdl)

02 03 04 05 06 07 08 09 10 11010

040BLENDS WITH 2MP2

PMMAPEG 0 10 20 30 40 Re

C (gdl)

0 10 20 30 40 5-01

PMMA PEG BLENDS

3MP2 2MP2 3MP1

other phase

(5050)

2MP2 0 34 16 35

3MP2 0 37 18 21

3MP1 0 58 28 19

544 FTIR Analysis

500 1000 1500 2000 2500 3000 3500 4000

20 PMMAPEG 0 Blend

Wave number cm-1

2750 2800 2850 2900 2950 3000 3050 3100-05

PEG PMMAPEG 0

Wave number cm-1

2750 2800 2850 2900 2950 3000 3050 3100

152MP2 in PMMAPEG

0 10 20 30 40

Wave number cm-1

cm-1 range

respectively)

500 1000 1500 2000 2500 3000 3500 4000

0 10 20 30 40

Wave number cm-1

500 1000 1500 2000 2500 3000 3500 4000

Wave number cm-1

500 1000 1500 2000 2500 3000 3500 4000

Wave number cm-1

3100 3150 3200 3250 3300 3350 3400 3450 3500 3550 3600 3650 3700 3750 3800

3MP1 IN PMMAPEG 40 30 20 10 0

Wave number cm-1

2MP2 40 3MP2 40 3MP1 40

Wave number cm-1

Conclusions

of the blends

CONCLUSIONS

Binder2pdf

Binder1pdf

page de gardedoc

Acknowledgementsdoc

OUTLINEdoc











SUMMARY lastdoc


CHAPTER I apresdoc





CHAPTER II 2doc

21 Introduction



CHAPTER III Apdf


CHAPTER III Baapdf

CHAPTER III Bbpdf

CHAPTER III Bcpdf

CHAPTER IV LASTpdf


References

CHAPTER Vpdf


51 Introduction

References

CONCLUSIONSpdf

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Ministère de l’Enseignement Supérieur et de la Recherche ...acrylonitrile-butadiene-styrene (ABS). These blends are tough and have good processability. One of the most interesting