Preparation and Properties of Organosoluble Polyimide/Silica Hybrid Materials by Sol-Gel Process

摘要

Organosoluble polyimide/silica hybrid materials were prepared using the sol-gel process. The organosoluble polyimide was based on pyromellitic anhydride (PMDA) and 4,4'-diamino-3,3'-dimethyldiphenylmethane (MMDA). The silica particle size in the hybrid is increased from 100-200 nm for the hybrid containing 5 wt % silica to 1-2 #mu#m for the hybrid containing 20 wt % silica. The strength and the toughness of the hybrids are improved simultaneously when the silica content is below 10 wt %. As the silica content is increased, the glass transition temperaure (T_g) of the hybrids is increased slightly. The thermal stabiltiy of the hybrids is improved obvisouly and their coefficients of thermal expansioin are reduced. The hybrids are soluble in strong polar aprotic organic solvents when the silica content is below 5 wt %.