Enhancement of surface electrical performances of epoxy film by blending with fluorinated and crosslinking monomer

Abstract

• Fluorinated monomers were synthesized through a facile method to prepare fluorinated epoxy films. • Effects of introducing –CF 3 groups on physicochemical characters of the films are studied. • Electrical strength of the fluorinated film was evidently enhanced. In order to introduce fluorine-containing functional groups into epoxy resins to stably enhance the surface electrical properties of thin films, the trifluoromethyl group containing diglycidyl ethers bisphenol A (F-DGEBA) monomer was prepared by a simple and environmentally friendly method. Further, the film was obtained by blending the prepared monomers with DGEBA in different proportions and curing at high temperature with methyl tetrahydrophthalic anhydride (MTHPA). The prepared films not only have improved hydrophobic properties, but also exhibit better surface electrical properties. With the increase of the content of F-DGEBA, the epoxy resin films have higher surface insulation strength and better potential decay performance, which is due to the existence of –CF 3 groups changing the distribution of deep and shallow traps. Compared with the non-fluorinated film, the flashover voltage of the fluorinated film with the best electrical properties is increased by 32.2%, and the potential decay rate is also much faster.