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| Volume 6, Issue 02 - 2010 |
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| 4 |
RELAXATION PHENOMENA IN CHITOSAN-CARBON NANOTUBE
BIONANOCOMPOSITES |
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| Pages 61-67 |
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| C. PEREZ1, E. PROKHOROV1*, G. LUNA-BARCENAS1, J. B. GONZALEZ-CAMPOS2, I.C. SANCHEZ3, J. GONZALEZ-HERNANDEZ4, M. E. MENDOZA DUARTE4, F. VILLASENOR-ORTEGA5 |
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1 Cinvestav del IPN, Unidad Queretaro, Juriquilla, 76230, Mexico
2 Universidad Michoacana de San Nicolas de Hidalgo, Morelia, Mich, 58060, Mexico
3 Department of Chemical Engineering, The University of Texas at Austin, Austin, TX 78712, USA
4 CIMAV, Chihuahua, Chih. Mexico
5 Instituto Tecnologico de Celaya, GTO, Mexico |
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| Received 12 April 2010; accepted 31 May 2010 |
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| For the first time, thermal relaxation properties of chitosan films with carboxy-functionalized multiwall carbon nanotubes MWCNTs (0.5, 1, 3, 5 and 10 wt. %) composites have been investigated. Depending upon MWCNT concentration three relaxation processes can be observed as a function of temperature and water content using dynamical mechanical analysis and dielectric spectroscopy in the temperature range of 25-330°C. Low temperature relaxation process, in the range 25-70 0C, can be related to the á-process associated with the glass-rubber transition and can be described by the Vogel-Fulcher-Tammann dependence of the relaxation time versus reciprocal temperature. The glass transition temperature is strongly affected by water content such that it vanishes in a dry material. The second relaxation was observed in the temperature range 70-190 0C and it is identified as the ó-relaxation which it is often associated with the hopping motion of ions in the disordered structure of the biomaterial. This relaxation exhibits a normal Arrhenius-type temperature dependence with activation energy of 81-86 kJ/mol and it is independent of water content. In the temperature region of 200-3000C we have observed a relaxation process that is associated to film degradation.
Keywords: N/A |
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