Polyimide-silica composite materials: How does silica influence their microstructure and gas permeation properties?
Composite polyimide-silica materials have been synthesized via the sol-gel process and their gas transport properties studied. Structural characterizations have been performed showing that materials prepared with large concentration of silicon alkoxyde are composites made of silica particles embedded in the polyimide matrix while low-silicon alkoxyde concentration induces homogeneous materials. X-ray diffraction shows that the presence of silicon species induces modifications in the microstructure of the polyimide chains. These modifications have been confirmed by a shift of the glass transition temperature and density variations. Influence of the temperature and silicon species on the gas transport have been studied using various gases (nitrogen, oxygen, carbon dioxide, and methane) showing that gas permeation coefficients increase with the silicon species proportion. CO{sub 2} sorption measurements have been performed at various temperatures and the results have been analyzed in terms of the dual sorption theory. Activation energies have been calculated for the permeation and sorption mechanisms. The results show that silicon species contributes to the overall permeability.
- Research Organization:
- CNRS-ENSCM-UM2, Montpellier (FR)
- OSTI ID:
- 20001166
- Journal Information:
- Chemistry of Materials, Vol. 11, Issue 9; Other Information: PBD: Sep 1999; ISSN 0897-4756
- Country of Publication:
- United States
- Language:
- English
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