The Effect of Powdered Layer on the Physicochemical Properties of Silicone Rubber Surface

Abstract

In this paper, the pulverization phenomenon of composite insulator shed from three different environmental conditions was studied. Several methods were used to test the effect of powdered layer on the physical and chemical properties of silicone rubber surface. Scanning electron microscopy (SEM) was used to observe the surface morphology of the materials. The hydrophobicity of insulator shed is characterized by static contact angle. The surface profile parameters of composite insulator are obtained by detecting the surface of composite insulator with a stylus roughness meter. EDS and FTIR were used to study the elemental composition and chemical groups. The dielectric parameters at different frequencies were obtained by broadband dielectric spectrum scanner. It was observed that the hydrophobicity, roughness and dielectric properties of the composite insulator sample become worse after removing the powdered layer, the chemical composition of the surface can be restored to the fresh state of the silicone rubber. However, the influence trend of powdering on the surface hydrophobicity of composite insulator is not uniform. For composite insulator with serious pulverization, the hydrophobicity will not be improved after removing the powdered layer. The surface roughness of composite insulator will increase greatly due to pulverization. The powdered layer on the surface of composite insulator is mainly composed of small molecules formed by degradation of silicone rubber main chain and fillers separated from the material. The dielectric properties will decrease slightly after de-powdering.