Investigation of acid rain impact on ATH/LMGP added hybrid silicone rubber composites adopting dielectric and thermographic methods

This is the authors' abstract. We don't add key points for this paper.

The present work examines the surface degradation and charge transport mechanism of silicone rubber material with nano-size alumina trihydrate (ATH) and low-melting glass powder (LMGP) fillers, aged in an acid rain solution. The immersion in acid rain forms acid/salt contamination layers on the silicone rubber surfaces. Scanning electron microscope images indicate that the acidic degradation could be minimized by LMGP addition with base silicone rubber. ATH/LMGP filler addition with silicone rubber significantly enhances the contact angle, thermal conductivity and reduces the diffusion coefficient. LMGP filler addition minimizes the formation of Si(–O) 4 , Si(–O) 3 , C–O and C=O components following the acid rain immersion. Equivalent circuit modelling of dielectric parameters explains the formation of a quasi-polaron surface polarization interface along with the Maxwell–Wagner interface in the acid rain-aged silicone rubber composites. A significant increase in real and imaginary permittivity is observed with the acid rain-aged silicone rubber samples. The surface potential decay experiment indicates a reduction in trap depth values in acid rain aged samples due to the fast surface potential decay characteristics. The thermal images and T vs F curves indicate that the ATH/LMGP filler addition reduces the local heat accumulated area (LHA). The huge variation in Haralick parameters has observed between the virgin and aged samples. However, considering multiple aging factors, such as ultra violet radiation, thermal cycling, and electrical discharge could accurately determine the overall degradation state of the insulators.