Microstructure,interfacial interaction,and properties of polyimide/poly(vinylsilsesquioxane)/titania ternary hybrid nanocomposites

Ternary hybrid nanocomposites of polyimide (PI), poly(vinylsilsesquioxane) (PVSSQ), and titania (PI/PVSSQ/Ti) were prepared by thermal imidization from 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA)-4,4'-oxydianiline (ODA) polyamic acid (BPDA–ODA PAA) and a sol-gel process from vinyltriethoxysilane(VSSQ) and titanium isopropoxide(Ti(OPr)₄). The microstructure, interfacial interaction, and optical and thermo-mechanical properties of the hybrid films have been investigated. The phase morphology and the properties are influenced by the composition of PVSSQ and titania. For the PI/VSSQ/titania ternary hybrid systems, the particle size is significantly decreased and the inorganic particles are extremely finely distributed in the nanometer scale, suggesting that the interaction between the particles and the matrix increases. It is concluded that the addition of titania plays a compatibilizing role for the PI/PVSSQ binary hybrids, resulting in the enhancement of optical transparencies and thermo-mechanical properties of the binary hybrids.