Water Absorption Resistance Study of HTV Silicone Rubber-Based Hybrid Composites

Silicone rubber-based insulating polymers are extensively used in high voltage outdoor applications due to their high hydrophobicity and better withstand performance. However, the main problem with polymeric composites is their aging due to external environmental stresses (e.g. direct sunlight, high humidity and temperatures, ultraviolet radiations, etc.) as well as strength of the applied electrical field. In the present work, for examining weight gain, hydrophobicity, and hardness, five different types of HTV silicone rubber-based hybrid composites are prepared. All the samples are reinforced with micro-alumina (20 wt. %) and different concentrations of silica fillers. Material samples are immersed in distilled and boiling water for 24h and 2h, respectively. For analysis, hydrophobicity, weight gain and hardness tests are conducted. The results of the performed tests indicated that the sample filled with 6 wt. % of nano-silica has less percentage gain in weight due to water absorption compared to the other hybrid composites. The sample with the same composition showed high hydrophobicity as well.