Preparation and characterization of the nano-doped polyimide film

In this paper, a kind of nano-doped polyimide composite film was made by synthesizing polyimide/inorganic nano-particle matrix resin through sol-gel technique, followed by rotating it on a silex glass plate and heating at high temperature. The effect of the size of the inorganic particle that derived from methyl-triethoxysilane, as a precursor of the inorganic moiety, in-situ in the polyamic acid solution on the corona-resistant property was studied. The miscibility between the organic and inorganic phases and its effect on the corona-resistant property was investigated with aminopropyltriethoxysilane, which serves as a coupling agent, added into the polyimide composite system. The chemical structure and the surface morphology of the film were characterized by FTIR, AFM respectively. The corona-resistant property was tested by rod-plate electrode. It proved that the corona-resistant property was enhanced with the increasing of size of the inorganic particle, and that it got excellent result with the size in the range from 100 to 500 nm. It also turned out that the presence of chemical bonds between two phases due to adding of the coupling agent had, to some extent, effect on the corona-resistant property of the film. In this article, furthermore, the factors and the principle of the effect on the corona-resistant property were discussed. The approaches how to enhance the corona-resistant property were put forward preliminarily.