Thermo-Mechanical Performance of Epoxy Hybrid System Based on CNTs and GNs

This work investigated the synergistic effect of combining multi-wall carbon nanotubes (CNTs) and graphene nanosheets (GNs) in epoxy composites prepared with two fixed filler amounts of 0.1 wt% and 0.5 wt%. These quantities are, respectively, below and above the electrical percolation threshold (EPT) of single filler systems, with varying five CNTs:GNs mix ratios. The hybrid composites showed exceptional electrical performance. The observed synergistic effect can be attributed to the establishment of strong π–π bond interactions between the multi-wall carbon nanotubes and the graphene layers dispersed in the epoxy resin and intense interfacial bonds with the polymeric matrix. This synergy was achieved with the addition of the smallest amount of GNs at 0.1 wt% of the nanofiller mix, leading to a significant increase in electrical conductivity and a reduction in EPT [1]. Mechanical performance evaluations were conducted in dynamic and static regimes, along with thermal analysis to also assess the thermal stability. The remarkable mechanical and thermal findings confirm the significant synergistic effect at a low hybrid nanofiller content of 0.1 wt%, correlating well with the electrical data. In fact, the CNTs acted as bridges between adjacent GNs, enhancing the load transfer and electrical properties. Particularly, the formulated hybrid samples demonstrated a glass transition temperature of 255 °C and high storage modulus values at elevated temperatures.