The Hybrid Films of Polyimide and Mercapto Functionalized Ladder-like Polysilsesquioxane: Preparation, Microstructure and Properties

Mercapto functionalized ladder-like polysilsesquioxane (LPMPSQ) has been synthesized by a conventional technique and the existence of ladder-like structure has been confirmed by Fourier transform infrared, X-ray diffraction and nuclear magnetic resonance. Then high performance polyimide (PI)/LPMPSQ hybrid films were prepared by incorporating the synthesized LPMPSQ into PI matrix. Both the aggregation and migration of LPMPSQ and the interfacial interaction between the two phases were investigated with scanning electron microscopy and X-ray photoelectron spectroscopy. The water absorption capacity and mechanical properties of the hybrid films were studied. The results indicate that aggregation and migration of LPMPSQ mainly occurred at the stage of solvent evaporation, and the interfacial interaction between PI and LPMPSQ was formed during thermal treatment. Since the interaction did not prevent the surface enrichment of LPMPSQ, PI/LPMPSQ hybrid film possessed rich silicon content on the surface, while maintaining excellent mechanical properties of PI.