Graphene–Epoxy Composites with High Dielectric Constant Prepared by Cryomilling

Abstract

The microstructure and dielectric properties of the graphene–epoxy composites prepared by cryomilling at liquid nitrogen temperature were studied by SEM and RF impedance material analyzer. The result indicated that both the dielectric constant and conductivity of the composites increased with the increase of the graphene content. The value of the dielectric constant of the composite with about 8 wt % of graphene was as high as 200. Moreover, the frequency dispersion behaviors of the conductivity within a certain frequency range accorded with the Jonscher's power law demonstrating that the conductive mechanism is hopping conduction. The negative reactance decreased with the increase of the testing frequency which indicated a capacitive character