Performance Evaluation of Thermally-Aged RTV Silicone Rubber/TiO2 Nanocomposites in Mineral Oil for Transformer Bushings

The room temperature vulcanized (RTV) silicone rubber is regarded as a coating material for power transformer bushings. However, the performance of silicone rubber may get severely degraded in the event of leakage of mineral oil from the transformer. Nevertheless, little attention has been paid to exploring the viability of silicone rubber nanocomposites in retarding transformer oil-induced damages. Therefore, this article investigates the effect of mineral oil on silicone rubber material doped with Titania (TiO<inline-formula> <tex-math notation="LaTeX">$_{{2}}{)}$ </tex-math></inline-formula> nanofillers. Silicone rubber nanocomposites with 1, 3, 5, and 7 wt% of nano-TiO2 were synthesized and thermally aged in transformer oil at 80 °C for 18 h. Performance evaluation was done based on the experimental outcomes of 3-D microscopy, Fourier transform infrared spectroscopy (FTIR), contact angle, corona inception voltage (CIV), thermogravimetric analysis (TGA), infrared (IR) thermography, surface potential, and water diffusion tests. Finally, based on the experimental investigations, 5 wt% nanocomposite was found to be superior in performance against transformer oil-induced degradation.