SOL-GEL POLYIMIDE-SILICA COMPOSITE FILMS - CORRELATIONS BETWEEN THE MICROSTRUCTURE AND THE SYNTHESIS PARAMETERS

Polyimide-silica composite films were obtained using the sol-gel proce ss by polycondensation of tetramethoxysilane in a polyamic acid soluti on. Various proportions of silica were introduced. The influence of th e synthesis parameters (water and precursor concentrations) on the fin al structure was studied using various techniques. The hydrolysis-cond ensation reactions in the polyamic acid matrix were followed by Si-29 NMR. The films were characterized by infrared spectrometry, thermograv imetric analysis, and scanning electron microscopy. These characteriza tions showed the influence of the silica and water content on the cond ensation kinetics, allowing the size of the si[ica clusters to be tail ored.