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INTRODUCTION Bustero Martínez de Zuazo, Izaskun; García Gallastegi, Ainara; Belsue Etxeberria, Mikel; Muñoz Gómez, Roberto. SYNTHESIS AND MANIPULATION OF CARBON NANOTUBES Carbon nanotubes can be used as sensors, hydrogen storage, membranes based on nanotubes, filters and reinforcement of polymeric composites. Multi wall carbon nanotubes (MWNT) have been synthesized by chemical vapor deposition (CVD). The MWNT were produced in a tubular reactor using methane as precursor and a metallic supported catalyst. The process generates MWNT material depending on the working conditions: catalyst material, catalyst layer thickness, deposition temperature and pressure . Hydrocarbon source Ar source Gases outlet (H 2 + CH 4 without react) Quartz reactor Tubular furnace vertical. Hydrocarbon source Ar source Catalyst Separator Gases outlet (H 2 + CH 4 without react) Quartz reactor Tubular furnace vertical. Termperature control WORKING CONDITIONS Tª 710ºC Gas flow 5.5L/H Time 5 hours Catalyst 1.2 g SCHEME OF THE SYNTHESIS PROCESS CHARACTERIZATION The carbon deposit was characterized by thermal gravimetric analysis (TGA). The TGA experiment was performed in air at a heating rate of 10ºC min -1 for the pristine sample. Several forms of carbon besides nanotubes are present. The results show the presence of amorphous carbon, graphite species, and carbon and metal nanoparticles as by- products formed during the process. MANIPULATION Thermal Gravimetric Analysis Atomic Force Microscopy INASMET is working in the upscaling of the synthesis of carbon nanotubes using fluidized bed in order to get specific MWNTs in high amount for industrial applications. On the other hand, INASMET will improve the working conditions to produce MWNTs with an homogeneous diameter and length distribution and also to controlthe amount of defect groups therein. Several functionalization groups will be tested for various applications. Particularly, INASMET is researching the functionalization of carbon nanotube for its union with polylactic acid in applications of bone implants FUTURE WORK Amorphous and crystalline carbon impurities and metal particles are removed from MWNT using techniques combined for purification: oxidizing gas and acid treatment with further filtration. Depending on the post-synthesis treatment there are a variable number of defects in the structures. The method for purification used by INASMET has been the gas oxidation at temperature 475ºC during 4 hours. This method avoids to damage the nanotubes structure. A good dispersion of synthesized carbon nanotubes is required for most of the applications and specially for a suitable characterization. A systematic study has been performed in order to find an appropriate medium for solubilization/dispersion of pristine carbon nanotubes: organic solvent dispersions using for example N-methylpirrolidone (NMP), N,N- dimethylphormamide (DMF), etc. The MWNTs dispersed in NMP are more stable than in DMF. Beside, the MWNTs concentration dispersed in NMP was around 2-3 mg/cm 3 . These values are higher than those that can be found in the literature. The figure corresponds to the AFM image of carbon nanotubes after purification and dispersion in NMP. PURIFICATION DISPERSION The samples were characterized using Digital Instruments Multimode Atomic Force Microscope. An statistical analysis of the MWNTs synthesized shows a diameter distribution ranged from 50 to100nm and length from 1 to 6 mm. The following image corresponds to the sample of nanotubes before purification onto amine-functionalized substrate. The illustration shows the presence of impurities around the nanotubes. AFM Tapping Mode(TM) image of Carbon Nanotubes, before purification using RTESP (Rotated Tapping Mode Etched Silicon Probes) at 300 kHz frequency. AFM Tapping Mode(TM) image of carbon nanotubes, after purification using RTESP (Rotated Tapping Mode Etched Silicon Probes) at 300 kHz frequency. Lost weight vs temperature 0 10 20 30 40 50 60 70 80 90 200 400 600 800 1000 1200 Tª (ºC) Lost weight (%) TGA curves of the MWNTs synthesized over Ni/Al 2 O 3 catalyst Variation of the lost weight of MWNTs with the temperature

SYNTHESIS AND MANIPULATION OF CARBON NANOTUBES Poster/Bustero.pdfSYNTHESIS AND MANIPULATION OF CARBON NANOTUBES Carbon nanotubes can be used as sensors, hydrogen storage, membranes

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Page 1: SYNTHESIS AND MANIPULATION OF CARBON NANOTUBES Poster/Bustero.pdfSYNTHESIS AND MANIPULATION OF CARBON NANOTUBES Carbon nanotubes can be used as sensors, hydrogen storage, membranes

INTRODUCTION

Bustero Martínez de Zuazo, Izaskun; García Gallastegi, Ainara; Belsue Etxeberria, Mikel; Muñoz Gómez, Roberto.

SYNTHESIS AND MANIPULATION OF CARBON NANOTUBES

Carbon nanotubes can be used as sensors, hydrogen storage, membranes based on nanotubes, filters and reinforcement of polymeric composites.Multi wall carbon nanotubes (MWNT) have been synthesized by chemical vapor deposition (CVD). The MWNT were produced in a tubular reactor using methane as precursor and a metallic supported catalyst. The process generates MWNT material depending on the working conditions: catalyst material, catalyst layer thickness, deposition temperature and pressure .

Hydrocarbon source Ar source

Catalyst

Separator

Gases outlet (H2+ CH4 without react)

Quartzreactor

Tubular furnacevertical.

Termperature control

Hydrocarbon source Ar source

Catalyst

Separator

Gases outlet (H2+ CH4 without react)

Quartzreactor

Tubular furnacevertical.

Termperature control

WORKING CONDITIONS

Tª 710ºCGas flow 5.5L/HTime 5 hoursCatalyst 1.2 g

SCHEME OF THE SYNTHESIS PROCESS

CHARACTERIZATION

The carbon deposit wascharacterized by thermal gravimetric analysis (TGA). The TGA experiment wasperformed in air at a heating rate of 10ºC min-1

for the pristine sample. Several forms of carbon besides nanotubes are present. The results show the presence of amorphouscarbon, graphite species, and carbon and metalnanoparticles as by-products formed during theprocess.

MANIPULATION

Thermal Gravimetric Analysis Atomic Force Microscopy

INASMET is working in the upscaling of the synthesis of carbon nanotubes using fluidized bed in order to get specific MWNTs in high amount for industrial applications.

On the other hand, INASMET will improve the working conditions to produce MWNTs with an homogeneous diameter and length distribution and also to controlthe amount of defect groups therein.

Several functionalization groups will be tested for various applications. Particularly, INASMET is researching the functionalization of carbon nanotube for its union with polylactic acid in applications of bone implants

FUTURE WORKFUTURE WORK

Amorphous and crystalline carbon impurities and metal particles are removed from MWNT using techniques combined for purification: oxidizing gas and acid treatment with further filtration.

Depending on the post-synthesis treatment there are a variable number of defects in thestructures. The method for purification used by INASMET has been the gas oxidation attemperature 475ºC during 4 hours. This method avoids to damage the nanotubes structure.

A good dispersion of synthesized carbon nanotubes is required for most of the applications and specially for a suitable characterization. A systematic study has been performed in order to find an appropriate medium for solubilization/dispersion of pristine carbon nanotubes: organic solvent dispersions using for example N-methylpirrolidone (NMP), N,N-dimethylphormamide (DMF), etc. The MWNTs dispersed in NMP are more stable than in DMF. Beside, the MWNTs concentration dispersed in NMP was around 2-3 mg/cm3. These values are higher than those that can be found in the literature. The figure corresponds to the AFM image of carbon nanotubes after purification and dispersion in NMP.

PU

RIF

ICA

TIO

ND

ISP

ER

SIO

N

The samples were characterized using Digital Instruments Multimode Atomic Force Microscope. An statistical analysis of the MWNTs synthesized shows a diameter distribution ranged from 50 to100nm and length from 1 to 6 µm.

The following image corresponds to the sample of nanotubes before purification onto amine-functionalized substrate. The illustration shows the presence ofimpurities around the nanotubes.

AFM Tapping Mode(TM) image of Carbon Nanotubes, before purification using RTESP (Rotated Tapping Mode Etched Silicon

Probes) at 300 kHz frequency.

AFM Tapping Mode(TM) image of carbon nanotubes, after purification using RTESP (Rotated Tapping Mode Etched Silicon Probes) at 300

kHz frequency.

Lost weight vs temperature

0

10

20

30

40

50

60

70

80

90

200 400 600 800 1000 1200

Tª (ºC)

Lo

st w

eig

ht

(%)

TGA curves of the MWNTs synthesized over Ni/Al2O3 catalyst

Variation of the lost weight of MWNTswith the temperature