Enhancement of electrical conductivity of epoxy using graphene and determination of their thermo-mechanical properties

A three-roll mill processing technique was used to disperse graphene nanoplatelets into epon 828 epoxy system. As a first step of this research, processing of graphene/epoxy nanocomposites was explored with different weight percent of graphene. After establishing an optimal and repeatable process to achieve good electrical properties, the materials were tested for thermal conductivity and mechanical properties. The xGnP-25 graphene nanoplatelet supplied by XG Science Inc. was used, the graphene average diameter was 25 microns and thickness was 6-10 nanometers. Mechanical mixing, sonication and three-roll mill dispersion techniques were investigated to disperse graphene in epon 828 epoxy. The study showed that three-roll dispersion is effective, repeatable and potentially scalable to disperse graphene in to epoxy to increase the electrical conductivity. The weight percentage of graphene used ranged from 0.5 to 5.0. Percolation threshold of graphene was found 1.0 wt. %. Through-the-thickness (T-T-T) or volume electrical conductivity increased by nine log cycles, thermal conductivity doubled and fracture toughness increased by one-third for 1.0 wt. % addition of graphene to epon 828. However, the mechanical properties remained almost unchanged.