The epoxy-based nanocomposites are emerging with the development of nanotechnology and have drawn more attention. It has been proved that the introduction of graphene oxide (GO), even with low content, could improve the space charge distribrition and dielectric properties of polymeric materials. In this paper, nano-graphene oxide particles are applied to modify the epoxy resin, and the surface charge characteristics of the composites under various temperature are investigated.

Epoxy/GO nanocomposites (EP/GO) with various contents were prepared through two-phase extraction method. Surface potential decay (SPD) behaviors at different tempertures were investigated. Based on the obtained data, trap energy level distribution of the neat epoxy resin and EP/GO composite is calculated and compared.

Obtained results show that the introduction of GO could increases the shallower trap density as well as decreases the deeper trap density at the same temperature. With the increase of temperature, the deep trap density is decreased while the shallow trap density is enhanced. This is because the elevated temperature increases the energy of the charges, so that the charges in the deeper traps could participate in the dissipation of the surface potential.

The introduction of GO results in the increase of shallower trap density, and which may accelerate surface charge dissipation and attribute to the reduction of temperature coefficient of conductivity of EP/GO composites.