Synthesis and characterization of polyimide silica hybrid composites

A new class of polyimide/silica composites with chemical bonds between the polyimide and silica network has been synthesized by the sol-gel reaction and characterized. The hybrid composite films were obtained by the hydrolysis and polycondensation of (3-aminopropyl)triethoxysilane (APTES) and tetraethoxysilane (TEOS) in N,N-dimethylacetamide solution (DMAc), followed by heating at 100, 200, and 300 degrees C. The presence of chemical bonds between polyimide (PI) and silica has great effect on the properties of polyimide films, especially on their mechanical properties. The modulus and ultimate strength of the hybrid composite films increased and elongation at break decreased with increased silica content. These hybrid films showed no apparent decrease in thermal decomposition temperature.