Surface Charge Decay of Epoxy Resin Treated by AP-DBD Deposition and Direct Fluorination

Both atmospheric pressure dielectric barrier discharge (AP-DBD) deposition and direct fluorination are effective methods to modify the surface electrical properties of polymer insulation. To investigate the surface charge decay properties of Al2O3-filled epoxy resin (ER) prepared by AP-DBD and direct fluorination treatments, before and after drying, samples were studied under various treatment parameters. The experimental results show that charge decay rates for AP-DBD and fluorinated samples are more than 90% after 5 days in ambient air. The corresponding bulk and surface resistivity is reduced when the charge decay rate increases. After a longer time, the surface charge on the fluorinated samples decays faster than those on the AP-DBD samples before drying. The hydrophilicity of the fluorinated samples significantly affects the surface charge decay after drying. After 100 days of storage, the decay rates for the fluorinated samples decrease with increased storage time (less than 9% after 100 days) while for AP-DBD treated samples the decay rates exceed 24%. The surface resistivity of the AP-DBD samples is always lower than that of the fluorinated ones. Therefore, for a long storage time, AP-DBD treatment may provide a better solution to the surface charge decay of ER than direct fluorination treatment, after drying.