Preparation and Characterization of Silica/Polyamide-imide Nanocomposite Thin Films

The functional silica/polyamide-imide composite films were prepared via simple ultrasonic blending, after the silica nanoparticles were modified by cationic surfactant-cetyltrimethyl ammonium bromide (CTAB). The composite films were characterized by scanning electron microscope (SEM), thermo gravimetric analysis (TGA) and thermomechanical analysis (TMA). CTAB-modified silica nanoparticles were well dispersed in the polyamide-imide matrix, and the amount of silica nanoparticles to PAI was investigated to be from 2 to 10 wt%. Especially, the coefficients of thermal expansion (CET) continuously decreased with the amount of silica particles increasing. The high thermal stability and low coefficient of thermal expansion showed that the nanocomposite films can be widely used in the enamel wire industry.