Due to the smooth surface and chemical inertia of aramid fiber, its interfacial bonding performance with epoxy resin is limited, which will cause internal defects of insulating pull rod such as dry spot and air gap. When the insulated pull rod is put into operation, the internal defects are easy to cause partial discharge or even breakdown under strong electric field. Therefore, the interfacial compatibility between aramid fiber and epoxy resin was studied by plasma modification method in order to improve the performance of insulating rod.

The aramid fiber was modified by plasma produced by argon dielectric barrier discharge. The treatment time and argon flow rate were changed respectively. The contact angle was measured by optical measurement to characterize the compatibility between fiber and epoxy resin. The microstructure of the fiber surface was observed by scanning electron microscope.

The results show that the surface of aramid fiber without plasma treatment is smooth, and the surface of treated aramid fiber is rough, uneven and has small fragments. When the treatment time is 120s and the argon flow rate is 2L/min, the effect is the best and the decrease range of contact angle is the largest.

Plasma treatment of aramid fiber will form pits and roughen the fiber surface, so as to increase the fiber surface area, improve the compatibility between fiber and epoxy resin, and improve the interfacial properties between fiber and epoxy resin.