Resistance to Tracking and Erosion of Silicone Rubber Material under Various Types of Precipitation

Abstract

Environment stress and contaminants have become more and more severe due to the development of industry. Outdoor polymer insulating materials in use may suffer from rainwater containing various chemical contaminants so that their resistance to tracking degrades. In this paper, the tracking resistance of high-temperature vulcanized silicone rubber (HTVSR) under various types of precipitation is evaluated by the incline-plane method, using artificial rainwater as a contaminant. The influences of ion concentration, acidity, and conductivity of rainwater on the energized silicone rubber material are studied. Experimental results reported here show that the degradation of the energized material increases with the ion concentration of the rainwater; the discharge current and the erosion of material increase. The conductive ions in rainwater could induce more tracking and discharge on the energized material surface, and acidic rainwater could accelerate the electrolyte process in the materials and dissolve the inorganic filler in silicone rubber. Although silicone rubber degrades under our process of accelerated aging using artificial rainwater, the ion concentration, acidity and conductivity of actual precipitation is insufficient to exert a significant degradation effect on silicone rubber. Silicone rubber can resist the erosion of even the most corrosive rainwater and does not fail.