The polyimide/TiO2 nanocomposite thin films have been successfully synthesized. The surfaces of TiO2 particles were chemically modified with a γ-glycidyloxypropyltrimethoxysilane (GPTS) functional group to enhance the compatibility with polymeric matrix and to avoid the aggregation of particles. The dispersion of surface modified TiO2 in polyimide film was greatly improved and it was confirmed by the scanning electron microscope (SEM) analysis showing that well dispersed nanosized TiO2 particles. Compare to thepolyimide/unmodified TiO2 (T5) nanocomposite film, the size of the TiO2 particles in the polyimide/surface modified TiO2 (T5-GPTS) film was substantially reduced due to the increased solubility of surface modified TiO2 (T5-GPTS). The mechanical properties, thermal stabilities and dielectric properties of polyimide/surface modified TiO2 (T5-GPTS) nanocomposite films were also systematically investigated.

Keywords: Polyimide, TiO2, Nanocomposite, Surface modification.