Effects of plasma modification on interfacial properties of aramid fiber reinforced epoxy for insulation pull rod

The interface bonding performance between epoxy resin and fiber in the manufacturing process of insulation pull rod is the key to directly ensure the electrical insulation and mechanical properties of insulation pull rod. If the compatibility between the two is poor, it will cause dry spots, air gap and other defects. Because the surface of aramid fiber is smooth and chemically inert, its interfacial adhesion with epoxy resin is limited. Therefore, it is necessary to modify the surface of fiber to improve the compatibility between the fiber and epoxy resin. As an effective physical modification method, dielectric barrier discharge plasma surface treatment has the advantages of high efficiency, flexibility and environmental protection. In this paper, the surface of aramid fiber was modified by argon dielectric barrier discharge plasma. By changing the treatment time and argon flow rate, the compatibility between the fiber and epoxy resin under different treatment conditions was characterized by optical measurement of contact angle. The changes of microstructure and chemical groups on the surface of fiber were observed by SEM and XPS. It was found that the treated aramid fiber surface became rough, which increased the fiber surface area. And a new oxygen-containing polar group was introduced to improve the content of fiber surface active group. The interfacial properties between fiber and epoxy resin were improved.