Effect of PDMS Concentration on the Flashover Voltage Improvement of Epoxy Resin by Plasma Modification

With the increase of voltage level in power systems, epoxy resin, as a commonly used insulating material, is prone to surface flashover under strong electric field. Research has shown that the use of low-temperature plasma to deposit silicon-containing films on the material surface could effectively improve the flashover voltage. In this paper, through treating the epoxy resin (EP) surface with Ar/Polydimethylsiloxane (PDMS)/Surface Dielectric Barrier Discharge (SDBD), the influence of PDMS addition (5, 15, 25 mL/min) on the surface properties of EP was studied. The results showed that with the increase of PDMS concentration, the morphology of the deposited silicon-containing film on EP surface changed from discrete particles to agglomerated coral-like structures, and then to stacked particles. Surface water contact angle and electrical insulating properties both showed a trend of increasing first and then decreasing, and the best surface performance appeared at PDMS addition of 15 mL/min, where the flashover voltage and water contact angle were increased by up to 75.2% and 61.5%, respectively. The improvement of surface properties is associated with the deposited silicon-containing film, with the changing of physical morphology and chemical compositions.