Effect of mixing sequences of γ-piperazine propylmethyl dimethoxysilane on the tracking and erosion resistance of silicone rubber

gamma-Piperazin propylmethyl dimethoxysilane (HD-110) was introduced into silicone rubber containing platinum catalyst to enhance the tracking and erosion resistance by two mixing sequences:adding HD-110 in the preparation of silicone rubber masterbatch (SR-1) or silicone compound (SR-2). The effects of HD-110 and its mixing sequence on the thermal stability, tracking and erosion resistance, and mechanical properties of silicone rubber were investigated by rubber process analyzer (RPA), transmission electron microscopy (TEM), extraction resistance test, thermogravimetric analysis (TGA) and inclined plane (IP) test. It was indicated that HD-110 could significantly improve the thermal stability and tracking and erosion resistance of silicone rubber. Especially, SR-1 could pass the IP test at 4.5 kV with a eroded mass ratio of 0.35 wt%, which was much less than the 5.34 wt% of SR-2. SR-1 also had better mechanical properties. RPA, TEM and extraction resistance test revealed that HD-110 in SR-1 could easily condense with the Si-OH groups of silica to make HD-110 stable in the silicone rubber matrix and improve the interfacial interaction between silica and silicone rubber. Therefore, under the continuous elution of conductive solution and the heat stress generated by dry-band arcing, HD-110 was stable enough to enhance the tracking and erosion resistance of silicone rubber.