Improvement of fluorosilicone resin on the tracking resistance of addition-cure liquid silicone rubber

Abstract

Enhancing the anti-fouling and tracking resistance of silicone rubber is important to expand its application in outdoor high voltage insulation field. In this work, fluorosilicone resin (FSR) was synthesized by the sol-gel reaction of perfluorooctyltriethoxysilane and ethyl silicate. The effect of FSR on the tracking resistance of addition-cure liquid silicone rubber (ALSR) was investigated by inclined-plane test (IPT), plasma irradiation test, static contact angle measurement, attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) and infrared thermal image. The results showed that FSR could effectively improve the tracking resistance of ALSR. When FSR content was 0.5 phr, ALSR/FSR passed the IPT without overcurrent in 6 h under the applied alternating voltage of 4.5 kV and the erosion mass was only 2.14 wt%. In addition, the anti-plasma irradiation of ALSR/FSR was enhanced. FSR could improve the hydrophobicity of ALSR and reduce the accumulation of contamination on the surface. During the IPT, FSR could delay the occurrence of intensive arc discharge and diminish the number of arc discharge. When the dry-band arcing happened, FSR could dissipate the injected charges and suppress the arc discharge. Thus, the tracking resistance of ALSR was enhanced.