Acid Aging Induced Room‐Temperature Vulcanized Silicone Rubber Flashover Mechanism and Enhancement via Nano‐ TiO ₂ Modific

ABSTRACT

Room‐temperature vulcanized (RTV) silicone rubber is widely used as external insulation, but long‐term exposure to acidic media degrades its insulating performance and reduces flashover voltage. This study examines RTV's chemical structure, surface properties, and flashover behavior after 30 days of immersion in a pH = 1 HCl solution, and evaluates nano‐TiO ₂ modification to improve acid resistance. Acid aging mainly hydrolyzes SiOSi and SiC bonds, producing SiOH groups that increase surface conductivity by reducing trap depth. After 30 days, the water contact angle drops by 42.4°, and the DC surface flashover voltage declines by 41.75% (dry) and 64.11% (wet–polluted). The degradation mechanism is that H ⁺ in the acidic solution attacks the polymer chains, promoting hydrolysis, increasing the proportion of shallow traps, disrupting the cross‐linked network, increasing surface conductivity, and aggravating electric‐field distortion at the air–silicone interface. TiO ₂ ‐modified RTV shows a contact‐angle loss of only 26.7° and flashover voltages 47.01% (dry) and 75.21% (wet–polluted) higher than unmodified RTV. The O atoms in TiO ₂ interact with Si in the RTV backbone, reorienting CH ₃ side chains and hindering H ⁺ diffusion, thereby slowing hydrolysis. This study provides experimental evidence and mechanistic support for RTV modification in acidic environments.