The role of Nano-sized Alumina tri-hydrate and Fumed Silica on the Erosion of Silicone Rubber under DC Voltage

This paper aims to investigate the effect of nano-sized alumina tri-hydrate on the DC erosion resistance of silicone rubber, using the inclined plane tracking and erosion test. Silicone rubber composite containing nano-sized alumina tri-hydrate is comparatively analyzed with reference to silicone rubber filled with fumed silica at loading level of 5 wt%. Moreover, commercial silicone rubber composites that contain micro-sized alumina tri-hydrate at high loading levels are used for reference. Thermal characterization of silicone rubber composites is presented using simultaneous thermogravimetric and differential thermal analyses. The results obtained indicate a correlation between the erosion resistance determined using the inclined plane tracking and erosion test under DC voltages and the level of interaction between the filler and the silicone rubber tethering the siloxane chains, thereby suppressing the depolymerization and promoting crosslinking of silicone rubber. It also appears that the loading level of nano-sized alumina tri-hydrate is an essential factor that needs to be considered in order to obtain an evident erosion suppression effect for the water of hydration.