Dependence of the electrical conductivity of graphene reinforced epoxy resin on the stress level

This paper focuses on electrical conductivity of epoxy based nanocomposites containing graphene particles. We show that adding 0.5 wt% of nanoparticles decreases electrical resistivity of the material more than two orders of magnitude. This effect is modeled with good accuracy using ordinary micromechanical homogenization schemes. Combination of mechanical and electrical tests shows that electrical conductivity of the epoxy-graphene composite depends on the level of tensile stress in the material. To explain this effect we assumed formation of microcracks from the very beginning of the loading process due to very high stress concentration at the particles.