Study on Mechanical and Corona-resistance Property of Polyimide/silica Hybrid Films

Polyimide/Silica (PI/SiO2) hybrid films were prepared through Sol-Gel route using tetraethoxysilane (TEOS) as inorganic precursors. The fracture morphologies of hybrid films were characterized by Scanning Electron Microscope (SEM). The result showed that the silica particles were dispersed finely in PI matrix, and the dispersity of silica particles didn't change with silica content. The sizes of inorganic particles changed little with silica content and they were all less than 100nm when the silica content was less than 15wt%. Moreover, the interface between inorganic and organic phases was clear. The sizes of silica particles reached hundreds nanometers, and the interface between two phases became obscure at silica content of 30wt%. The mechanical properties measurement showed that the tensile strength and elongation at break of hybrid films were influenced by silica content. The two parameters got to maximum at silica content of 3wt%. The corona-resistance measurement showed that the corona-resistance property of hybrid films was improved by introducing silica. And the corona-resistance time was 180h at silica content of 30wt%.