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1
Les futures fibres
cellulosiques artificielles.
Procédés écologiques
pour générer des fibres
de demain
Patrick Navard Centre de Mise en Forme des Matériaux (CEMEF)
Ecole des Mines de Paris-CNRS
France
version 0.4
2
Biomass-based polymer
activities in CEMEF
Basic and applied research
20 active projects with industry
Industrial Chair “Bioplastiques” 2009 –
2013
Durable bioplastics
EPNOE:
European
Polysaccharide Network of
Excellence
0
0.2
0.4
0.6
0.8
1
1.2
1.4
3.0 4.0 5.0 6.0 7.0log Molar Mass
Dif
fere
nti
al
We
igh
t F
rac
tio
n
SE DP 360 original wood pulp,
SE DP 360 fraction 1,
SE DP 360 fraction 2,
SE DP 360 fraction 3,
SE DP 360 fraction 4 ,
Soluble
fraction
(4)Insoluble
fractions
(1, 2, 3)
0
0.2
0.4
0.6
0.8
1
1.2
1.4
3.0 4.0 5.0 6.0 7.0log Molar Mass
Dif
fere
nti
al
We
igh
t F
rac
tio
n
SE DP 360 original wood pulp,
SE DP 360 fraction 1,
SE DP 360 fraction 2,
SE DP 360 fraction 3,
SE DP 360 fraction 4 ,
Soluble
fraction
(4)Insoluble
fractions
(1, 2, 3)
3
Content
A: Introduction: cellulose fibres
B: Present fibres: properties and difficulties
C: Fibres coming from new solvents
D: Conclusions
4
A: Introduction: cellulose fibres
B: Present fibres: properties and difficulties
C: Fibres coming from new solvents
D: Conclusions
5
algae
sea animals (tunicin) cotton
trees
bacteria fungi
Cellulose sources
6
Cellulose is the most abundant natural polymer on Earth.
Cellulose cannot be melted.
Cellulose must be either solubilized or derivetized.
Cellulose is a « normal » polymer.
7
Organisation of a natural fiber
- fiber diameter: 10-30 microns
- a very complex “composite”:
cellulose, lignin, hemicellulose,
proteins
- the composition varies a lot!
almost pure cellulose 50-95% cellulose
8
A: Introduction: cellulose fibres
B: Present fibres: properties and
difficulties
C: Fibres coming from new solvents
D: Conclusions
9
0
10
20
30
40
50
60
1950
1960
1970
1980
1990
2000
2010
cellulosics
Synthetics
Cotton
wool
Mean fibre consumption
per kg per person
*Source: Lenzing AG
Examples of fibres
constant increase (2 à 3% per
year)
cotton culture is not increasing
sustainability issues
10
Why to use cellulose fibres ?
Confort in wet environment, softness
This is due to the special properties of cellulose
towards water: very hydrophylic, but not soluble
Existence of many h-bonds around cellulose
molecules water affinity
Hydrophobic moieties no dissolution in
water
Swelling of fibers in water associated with an
increase of mechanical resistance
11
20-60s
0 s
Swelling of a
regenerated cellulose
fibre
Swelling of cotton
fibre
12
Two main choices
Cotton
Cultivated in fields
Cotton hairs are nearly pure cellulose
Viscose
Based on cellulose extracted from wood or other plants
Spun from a cellulose derivative solution
13
Cotton fibres
World production : 25 million tonnes annually,
accounting for 2.5% of the world's arable land.
Pesticides: about 25% of pesticides used in the World.
Water use: 2.6 per cent of the global water use. As a
global average, 44 per cent of the water use for cotton
growth and processing is not for serving the domestic
market but for export. Consumers in the EU25
countries indirectly contribute for about 20 per cent to
the desiccation of the Aral Sea.
A.K. Chapagain et al, the water footprint of
cotton consumption, Research Report Series No. 18, Unesco September 2005
14
Viscose fibres
World production : 14% of artificial fibres (clothes, tires).
Invented by French scientist Hilaire de Chardonnet in 1891. Three British
scientists, Charles Frederick Cross, Edward John Bevan, and Clayton Beadle
patented the process in 1902.
Preparation: pulp is dissolved in caustic soda and it is shredded and allowed to
age. The aged pulp is then treated with carbon disulfide to form a yellow-
colored cellulose xanthate, which is dissolved in caustic soda again. Spinning
then regeneration (acid media or temperature).
Cellulose cellulose xanthate cellulose
Pollution: carbon disulfide and other by-products of the process.
15
Which solutions?
Decrease environmental pressure of cotton growing
« Coton bio »
Decrease pollution of viscose process
Possible but very costly
Use other sources
Bacterial cellulose ??
Use other solvents
Only one is industrialized (Lyocell process)
Need to find other solvents
16
A: Introduction: cellulose fibres
B: Present fibres: properties and difficulties
C: Fibres coming from new solvents
D: Conclusions
17
New solvents for processing cellulose fibres
Three main possibilities
• Lyocell process (not really new)
• NaOH-water
• Ionic liquids
18
Solution preparation Pumping (up to 30bars)
regeneration finishing
Air gap treatment
Filtering and spinning (through spinneret :40-400mm)
O
C
N
H
LYOCELL Process
cellulose processing in N-methylmorpholine-N-oxide / water
19
From Chanzy et al, Journal of Applied Polymer Science, 1983
RAMIE FIBRES
A: Dissolution
B: Only irreversible
swelling
C: Only reversible
swelling
D: Inactivity
phase diagram NMMO – H2O
D C B A
Dissolution, swelling and inactivity zones
20
Lyocell fibres: spun from a NMMO solution
Comparison with viscose fibres in both dry and wet states :
higher tensile strength
higher modulus
higher tear strength
lower strain at break
The textile properties in the wet state are very good.
BUT: high tendency to fibrillation
21
0,0
10,0
20,0
30,0
40,0
50,0
60,0
Percentage
(%)
<50 nm [50-100 nm] [100-500 nm] [0.5-1 µm] [1-2 µm] >2 µm
Ranges of fibril diameters
0,0
10,0
20,0
30,0
40,0
50,0
60,0
Percentage
(%)
<50 nm [50-100 nm] [100-500 nm] [0.5-1 µm] [1-2 µm] >2 µm
Ranges of fibril diameters
0,0
10,0
20,0
30,0
40,0
50,0
60,0
Percentage
(%)
<50 nm [50-100 nm] [100-500 nm] [0.5-1 µm] [1-2 µm] >2 µm
Ranges of fibril diameters
0,0
10,0
20,0
30,0
40,0
50,0
60,0
Percentage
(%)
<50 nm [50-100 nm] [100-500 nm] [0.5-1 µm] [1-2 µm] >2 µm
Ranges of fibril diameters
warm humid air gap and precipitated in water
cold dry air gap and precipitated in water
Normal atmosphere and precipitated in water
normal atmosphere and precipitated in NaOH
22
Under mechanical stress, in wet state, fibres fibrillate: fibrillation is
linked to the strong orientation of cellulose chains.
Dangerous process
Environmentally safe (99.8% solvent recovery)
Source: Ducos et al., 2005
23
Net NREU (GJ/t fibre), Cradle-to-factory gate
plus post-consumer waste incineration
with energy recovery (recovery rate = 60%primary energy)
Cotton (U
S&CN)
PET (W.Europe)
PP (W.Europe)
PLA fibre, w
ithout w
ind
PLA fibre, w
ith w
ind
Lenzing Viscose Asia
Tencel, Austria
Lenzing Modal
Tencel, Austria
, 2012
Lenzing Viscose Austria-40
-20
0
20
40
60
80
100
Net NREU
Net NREU, lower range
Net NREU, higher range93
85
62
43
2536 22 19
-10 -14
-29
-9 -9 -9 -9 -9
Cradle-to-factory gate
Recovered energy from
waste incineration
(energy recovery rate 60%)
Cotton: 26
-11 -11
66
39
Li Shen and Martin Patel
Utrecht University
24
Net Global Warming Potential (t CO2 eq./t fibre), Cradle-to-factory
gate plus post-consumer waste incineration
with energy recovery (recovery rate = 60%primary energy)
Cotton (U
S&CN)
PET (W.Europe)
PP (W.Europe)
PLA fibre, w
ithout w
ind
PLA fibre, w
ith w
ind
Lenzing Viscose Asia
Tencel, Austria
Tencel, Austria
, 2012
Lenzing M
odal
Lenzing Viscose Austria
-1
0
1
2
3
4
5
6
Net GWPlower range
Net GWPhigher range
-0.3
GHG emissions from waste
incineration (energy recovery
rate: 60%)
Cradle-to-factory gate GWP
(including carbon sequestration)
2.0
1.1
4.0
1.5
2.7
1.5 3.9
0.9
1.2
0.9
0.15
0.9
0.03
0.9
-0.25
0.9
Cotton: 3.1
2.6
0.9
1.2
1.2
25
Cotton (U
S&CN)
Lenzing V
iscose A
sia
PET fibre
(W.E
U)
PP fibre
(W.E
U)
Tencel, Austri
a
Lenzing M
odal
Lenzing V
iscose A
ustria
Tencel, Austri
a 2012
NO
GE
PA
Sin
gle
-sc
ore
po
ints
(Fir
st
no
rma
lise
d t
o W
orl
d 1
995
)
0
1050
60
70
80
90
100
Global warming
Abiotic depletion
Ozone layer depletion
Human toxicity
Fresh water ecotoxicity
Terrestrial ecotoxicity
Photochemical oxidation
Acidification
Eutrophication
Single-score result
NOGEPA weighting factors (normalised to world)
1 tonne fibre, cradle-to-factory gate, cotton =100
Weighting factors (NOGEPA)
Climate Change 32
Abiotic depletion* 8
Ozone layer depletion 5
Human toxicity 16
Fresh water ecotoxicity 6
Terrestrial ecotoxicity 5
Photochemical oxidation 8
Acidification 6
Eutrophication 13
Total 99
Source: Huppes et al (2003),
except for abiotic depletion
(marked with *), which is not
excluded by Huppes et al. and
is determined based on own
estimation.
26
Na-OH Process
• Look simple: NaOH + water + cellulose at low
temperatures (- 5°C)
• No pollution
• Invented during the 80’s by Japanese scientists
• Huge amount of research in Asia (mainly China
now) and Europe
• But suffers major drawbacks
27
Buckeye VFC
swollen in 8 % NaOH – water -5°C
Borregaard VHF
swollen in 8% NaOH – water -5°C
Bad, even very bad solvent
In 8% NaOH-water at -5°C under agitation, cellulose dissolves,
but not very well, with many undissolved parts remaining.
Solutions are gelling
28
Need to increase solubility and decrease gelation
• Need complex pre-treatments
of cellulose pulps
• Need adding additives like ZnO
of urea
Un-treated solution
• Not yet ready, if ever
0.01
0.1
1
10
0 300 600 900time, min
G', G'', Pa
G', 20°C
G'', 20°C
G'', 25°C
G'', 25°C
tgel tgel
5% cellulose in 9%NaOH/water
29
Cellulose solvents:
Dissolution:
[7% -10%] NaOH
Intensive mixing for 2 hours at [-6°C - +1°C]
- NaOH-water
- Imidazolium-based Ionic Liquids:
, melting point: ~60°-70°C , room temperature liquid
Dissolution: heating and stirring for several hours
- Cellulose • Microcrystalline cellulose = “cellulose”, DP 170
• “other” native celluloses: DP 300, 500, 1000
• bacterial cellulose, DP 4420
30
Ionic liquids
Ionic liquids (IL): new green cellulose solvents
- non-toxic (is it sure ?) and non-volatile
- high termal stability
- possible to dissolve high cellulose concentrations without
pre-activation
- can be tuned due to modifications in anions or cations
- expensive, but possible to recycle
31
Ionic liquids
Imidazolium-based Ionic Liquids:
, melting point: ~60°-70°C , room temperature liquid
No commercial product yet
32
A: Introduction: cellulose fibres
B: Present fibres: properties and difficulties
C: Fibres coming from new solvents
D: Conclusions
33
What is the future of cellulose fibres ?
• It must be proved that they offer a REAL advantage
over other fibres in terms of environment footprint.
• New, water-based solvents must be designed.
• Recent advances about hydrophobicity of cellulose
offer reasons to hope that new solvents can be
designed.
34
CEMEF
www.cemef.mines-paristech.fr
www.epnoe.eu
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