Surface modified polymer insulator with nano-sized cavities

Surface flashover properties of polymer insulator are very closely related to its surface structure and morphology. To enhance the surface flashover voltage of polymer insulator, nano-SiO2/cross-linked polystyrene (CLPS) composites with modified surface structure of nano-sized cavities were developed by means of both free radical crosslinking copolymerization and surface erosion for the first time. The structures of SiO2/CLPS composites were characterized with Fourier transform infrared spectroscopy(FT-IR) and transmission electron microscopy(TEM). The results showed that nano-SiO2 particles with an average size of 20-50 nm were well dispersed in the cross-linked polystyrene matrix with excellent compatibility between the organic and inorganic components. The cavities with the same size as SiO2 particles could be formed in the surface of the polymer, and SiO2 particles in the inner layer would remain intact. The uniform cavities could be responsible for the improvement of surface flashover property of polymer insulator. The surface flashover voltages of the modified surface insulators were increased by 15%-20% by comparison with that of CLPS. It gives a novel way to develop high dielectric polymer insulator.