Synthesis and characterization of corona-resistant nanocluster-trapped polyimide/silica composites

A new class of corona-resistant films made of nanocluster-trapped polyimide/silica composites that were synthesized by the sol-gel reaction was obtained by the hydrolysis and poly-condensation of tetraethoxysilane (TEOS) or methyl-triethoxysilane (MTEOS) in the solution of polyamic acid(PAA) dissolved in N,N-dimethy-lacetamide (DMAc), followed by heating. The chemical structure and the surface morphology of the composites films were characterized by Atomic Force Microscope (AFM)- and Fourier Transform Infrared Spectroscope (FTIR). The corona-resistant capacity of the composites films was tested under high voltage using rod-plate electrode. The compatibility between the organic phase polyimide (PI) and inorganic phase silica (SiO₂) had great effects on the properties of PI/SiO₂ films, especially on their corona-resistant capacity. And this capacity of the Nanocluster-trapped PI/SiO₂ films increased with increased content of silica.