The size effect of unmodified and graphene nanoparticle modified epoxy matrix is experimentally investigated. A significant size effect due to a statistical defect distribution is identified for the neat matrix. The graphene modified matrix shows almost no size effect. Failure initiates at the nanoparticles, counteracting any size effect due to a statistical defect distribution. In a bulk volume, energy dissipation mechanisms play a more important role, therefore higher values for tensile strength, compared to the neat matrix, are obtained with a nanoparticle modification.
