Evaluation of surface degradation of silicone rubber under natural tropical aging using thermogravimetric and thermomechanical analysis

Silicone rubber is a new insulating material for HV outdoor insulators. In order to know the long term of its performance we investigated the aging of the material under a natural tropical environment. This paper reports the investigation results on surface degradation of silicone rubber with different filler content which were installed in the open air in Bandung city, Indonesia, for 120 weeks by using thermogravimetric analysis (TGA) and thermomechanical analysis (TMA). The test results showed that adding a higher filler content improved the surface of RTV and HTV silicone rubber. The RTV with 29,2% filler content showed less surface degradation than RTV with 18% filler content; RTV with 22,9% filler content, and HTV with 72% filler content also showed less surface degradation than HTV with 48% filler content and also less surface degradation than HTV with 60% filler content. SEM photographs confirmed the results that both RTV with 29,2% filler content and HTV with 72% filler content had a little difference from those virgin samples