Surface charge characteristics of direct-fluorinated epoxy /TiO2 nanocompsite

Epoxy resin is widely used in electronic and electrical devices because of its excellent insulation properties. The surface charge accumulating on epoxy resin may cause electric field distortion which would lead to surface flashover. That TiO 2 nano particles were doped in the epoxy resin can enhance the mechanical properties and the resistance to tracking failure. However the mechanism of surface charge is seldom discussed. Meanwhile, fluorination will not destroy the original characteristic of organic polymer and improve the defects of polymer. In this paper, TiO 2 nano particles were dispersed in samples with weight ratios of 2, 4, 6, 8 wt%. The undoped samples were employed as a comparison. After different fluorination time of 0, 30, 60, 90 and 120 min respectively, surface charge accumulation and decay behavior were measured by an electrostatic voltmeter. The results proved that the addition of nano particles slowed down decay process of surface charge. The lowest decay rate appears at 6 wt%. However, fluorination can accelerate decay process. Taking all these into consideration, comprehensive insulation properties can be improved.