Investigation Properties of Silicone Elastomer Insulation with Difference Composition Nanofiller SiO2+ATH Under Artificial Tropical Climate Aging

Outdoor polymer insulators are often subject to various stresses such as severe environments and corona discharges that can alter the chemical structure of basic polymer and degrade surface properties. Considering the most significant influences from the tropical environment, significant changes in the dielectric and mechanical properties can be observed indicating bulk defects of the materials. This paper investigates the level of composition of $\mathrm {SiO_{2}}$ nanofillers and alumina trihydrate (ATH) nanofiller on silicone elastomers to improve their properties as outdoor high-voltage insulators. We have created test material from the resin of silicone rubber RTV683 with a mixture of nano silica powder (20 nm) and nano ATH powder (20-30 nm). The stoichiometric ratio of resin, filler, and hardener compositions varied (80-95: 5-20: 3-7.5). To determine its performance, the specimens were aged in the test chamber with given ambient conditions (relative humidity from 70±5 to 90±5%, temperature from 50 to 70°C, high-voltage stress of 20 kV and UV radiation) simultaneously during 720 hours (30 days). The experiment results showed that the absorption of moisture in the silicone elastomer of different filler content varied from 0.06% to 0.36%, Samples with higher filler content showed higher moisture absorption. The dielectric properties (relative permittivity is 3-4) and the hydrophobicity of the silicon elastomeric surface did not decrease under the pressure of the artificial tropical climate, even the contact angle of the water droplets increased (>90° the mechanical properties (tensile strength) were 1.22-2.54 N/mm$^{2}$). The phenomenon of scattering of nanofiller particles on the sample surface was analyzed by SEM, EDX and FTIR.