The Improvement in Electrical Properties of RTV Silicone Rubber by the Introduction of TiO₂ Nanocomposite

The room temperature vulcanized silicone rubber coating (RTV) is one of the most extensively used materials to improve the performance of composite insulator due to its preferable dielectric properties. However, the complex operating environment may lead to the degradation of RTV coating. In this paper, the effect of doping ratio of TiO2 nanoparticles on the electrical properties of RTV coatings was investigated. The TiO2 nanoparticles were modified by $\gamma$-Methacryloxypropyltrim-ethoxylsilane (KH570) and then added to the RTV composites with different doping ratios. The morphology, chemical structure and dispersity of the modified TiO2 were measured with SEM and Fourier FTIR methods. In addition, the characteristic of surface potential attenuation and flashover voltage of the TiO2/RTV composite materials were studied systematically. The results showed that TiO2 nanoparticles were uniformly dispersed in RTV coating and the -CH2-, Si-O-C and other functional groups were grafted on the TiO2 successfully. Besides, the number of surface deep traps increased due to the TiO2, nanoparticles which increased the flashover voltage of composite polymers. Based on the experiment, it was verifed that the addition of 3wt% TiO2/RTV composite could be an attractive approach to improve the electrical properties.