Resistance of polyimide/silica hybrid films to atomic oxygen attack

Polyimide/silica (PI/SiO2) hybrid films were prepared by the sol–gel process to improve the erosion resistance of polyimide materials in atomic oxygen (AO) environments. The p-aminophenyltrimethoxysilane (APTMOS) was used as a coupling agent to enhance the compatibility between the PI and SiO2. The effects of the APTMOS addition on the morphology and property of the PI/SiO2 hybrids were investigated using UV–Vis spectrophotometer, FTIR spectroscopy and SEM. The thermal properties and AO resistance of the PI/SiO2 hybrids were investigated by TGA and in the AO simulator, respectively. The results showed that the addition of APTMOS remarkably reduced the size of the silica particles, the PI/SiO2 hybrid films became transparent, and the compatibility between the PI and SiO2 and the thermal stability of the hybrids were significantly improved. During AO exposure, a passive inorganic SiO2 layer was formed on the PI/SiO2 hybrid films, causing the hybrid films to possess excellent AO resistance. The optical properties of the PI/SiO2 hybrid films were not altered after AO exposure.