Exploring the dielectric properties of HTV silicone rubber based hybrid composites in a multi-stress aging environment

Abstract

High temperature vulcanized (HTV) silicone rubber experiences deterioration in electrical performance when subjected to prolonged environmental stresses, limiting its effectiveness in insulation applications. This study investigates the electrical properties of HTV silicone rubber hybrid composites reinforced with nano-silica (2–10%) and micro-ATH (20%) under multi-stress aging for 9000 hours. The results show that hybrid composites exhibit improved electrical performance compared to neat silicone rubber. Notably, the SAT-6 composite displayed the highest DC resistivity (532.57 × 10¹³ Ω m) at 60 °C before aging, with only an 18.5% reduction after aging. SAT-2 demonstrated the smallest increase in the dielectric constant and tan δ, indicating better aging resistance. In contrast, SAT-10 showed the lowest resistivity and the highest increase in dielectric losses due to filler agglomeration and poor dispersion. Overall, leakage current increased after aging, but SAT-6 maintained the lowest value among all aged samples, while SAT-0 showed the highest. These results confirm that the optimal filler loading significantly enhances aging resistance, with up to 6.57% minimal loss in resistivity for SAT-6 at room temperature. These findings show the strong potential of HTV silicone rubber hybrid composites for industrial application in outdoor high-voltage insulation, where improved dielectric stability and long-term durability are critical, enabling reduced maintenance and enhanced reliability in power infrastructure.