Investigation of electrical-mechanical performance of epoxy-based nanocomposites filled with hybrid electrically conductive fillers

This study aimed at investigating the influence of utilizing electrically conductive nanofillers such as graphene nanoplatelets (GNP) and carbon nanotubes (CNT) as secondary fillers on the electrical-mechanical behavior of epoxy/synthetic graphite (epoxy/SG) composites where SG was a microfiller. The composites were prepared by an internal mixer and compression molding and the electrical-mechanical behavior of the composites was characterized by the measurements of the in-plane and through-plane electrical conductivity as well as the flexural strength and modulus. The microstructure of the composites was examined by scanning electron microscopy (SEM). The results showed that the addition of GNP to epoxy/SG composites in the expense of SG had a negative impact on the electrical conductivity as the GNP content increased up to 10 wt%. Composites containing M-grade GNP with a particle size of 15 μm showed higher in-plane and through-plane conductivity values compared to that having the C-grade GNP with particle size less than 2 μm. The incorporation of CNT to the epoxy/SG/GNP composites had a pronounced improvement to the electrical and flexural properties. The maximum values of in-plane and through-plane conductivity reported were almost equal of about 41 S cm^-1 for composites containing a GNP:CNT weight ratio of 4:6. The effect of fillers morphologies and distribution on the behavior of the composites was also investigated.