Effect of Different Carbon Materials on the Conductivity of Epoxy Resin Conductive Coatings

In this work, the conductive coating was prepared by electrostatic spraying with graphene and Multi-walled carbon nanotube (MWCNTs) as conductive medium and epoxy resin powder as film-forming material, in order to solve the pro·blem of high content and uneven dispersity of conductive particles in conductive coatings prepared by brushing method. The resistance of the coating was measured by four probe method, the dispersity of conductive particles in the coating was analyzed by scanning electron microscope (SEM), and the conductive mechanism of the coating was analyzed by percolation theory model. The results show that the conductive particles can be dispersed evenly in the whole coating by electrostatic force. Meanwhile, the electrostatic force can also stretch the conductive particles in the coating along the direction of the thickness of that. The flake graphene is vertically arranged in the coating, and the curled MWCNTs forms the conductive network of "island-bridge" structure. The conductive particles laped each other to form a conductive path, which greatly reduced the content of conductive particles. The seepage threshold of graphene conductive coating was only 1.5 wt.%, which lower than that of the MWCNTs conductive coating, which is 3 wt.%. The resistance of epoxy coating containing with 0.5 wt.% graphene is 3397 Ω·m, and that of epoxy coating containing with 0.5 wt.% MWCNTs is 1049 Ω·m.