Temperature Dependent Surface Charge and DC Flashover Voltage of Fluorinated Polypropylene Film

The characteristics of surface charge and DC flashover voltage of fluorinated polypropylene (PP) film at different temperatures were investigated in work. Corona charging and surface potential decay (SPD) experiment were conducted at temperatures varying from 20 to 80 °C, with the relative humidity of ∼25%. The DC flashover voltage was measured using a pair of finger electrode. The characteristics of trap distribution at different temperatures were calculated and analyzed. Fluorination can effectively inhibit the injection and accumulation of surface charge at temperatures varying from 20 to 80 °C. Both the shallow trap level (STL) and the deep trap level (DTL) of fluorinated PP film become shallow. The elevated temperature increases the de-trapping probability of surface charges, leading to the decrease of DC flashover voltage. The results indicate that fluorination caused the variation of surface state of PP film, and inhibits surface charge injection and accumulation at different temperature. The decreased surface charge inhibits the distortion of electric filed and then increase the flashover voltage even at elevated temperatures.