THERMOSTABLE EPOXY-SILICA COMPOSITES OBTAINED BY A SIMPLIFIED SOL-GEL METHOD
Based on the UP-650T cycloaliphatic oligomer and tetraethoxysilane (TEOS), epoxy-silica composites were synthesized. The content of SiO2 in composites was 0.5-10%. Samples are obtaining by a simplified sol-gel technique without exemplary formation of filler particles. The effect of silica content on the thermomechanical properties of composites and their stability to thermal oxidative degradation were studied. When nanosilica is introduced into the amine-cured polymer matrix, two opposite effects (plasticization and reinforcement) are superimposed. Formation of three-dimensional silica networks leads to reinforcing of composites polymer matrix and reduces elongation of film samples on 1-2 order. Silica filler, synthesized by the sol-gel method, increases the thermal stability of composites: the intensive stage of destruction begins at higher temperatures, the temperature of the 50% weight loss of samples increases by 79 °C. Epoxy-silica composites oxidize at a slower rate.