Effect of release agent on arc ablation resistance of epoxy resin

Epoxy resin is a kind of outstanding material in electric-power equipment, especially in some ultra-high voltage system. Release agent is the essential interface agent applied in the demolding of epoxy insulator, which may remain on the surface of the insulator, influencing the safety of operation. In this paper, the arc ablation resistance of the epoxy sample with and without release agent was tested to judge the interface properties. The release agent remained on the surface of samples has degraded the performance of the resistance of arc ablation, the failure time become shorter and the ablation area become smaller when the release agent is applied. The infrared spectroscopy analysis and the thermal decomposition property analysis indicated that the release agent applied in epoxy is a kind of siloxane compound, which may bring moisture and electrolytes, generating the leakage current on the surface of the sample. Partial carbonization is initiated by heat produced by leakage current and the arc which make it easier to form a carbonized path connected the electrodes. This study will help to improve the interface process in the manufacture.