Comparison of four commonly used high temperature vulcanized silicone rubber formulas for outdoor insulator and their regional adaptability

Abstract

ABSTRACTHigh temperature vulcanized silicone rubber (HTVSR) insulators are widely used in transmission lines. In this article, four formulas [fumed silica and precipitated silica as reinforcing agent, alumina trihydrate (ATH) and alumina as flame retardant, and Fe2O3 and Fe3O4 as colorant] widely used in the production of HTVSR insulators were investigated by performing a series of laboratory experiments. The surface morphologies of silicone rubber, mechanical characterization (hardness, tensile property, and tear strength), electrical properties (volume resistivity, dielectric property, and breakdown strength), hydrophobicity and its transfer property, and thermal property of these four formulas were analyzed. According to the test results, the formula composed of fumed silica, Fe2O3 colorant, and alumina trihydrate (ATH) were excellent in mechanical properties because of more secondary structures, more bound rubber, and uniform dispersion. Therefore, it can be used in strong wind and bird pecking regions. Due to the absence of crystal water, the formula composed of fumed silica, Fe2O3 colorant, and alumina was observed to be excellent in thermal stability and electrical properties, making it suitable for the regions with high temperature and humidity. The formula composed of precipitated silica, Fe3O4 colorant, and ATH was found to be excellent in hydrophobicity transfer characteristics because of more raw rubber and satisfactory performance could be expected when it was applied in polluted regions. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47477.