Synergistic effect between graphene nanoplatelets and carbon black to improve the thermal and mechanical properties of natural rubber nanocomposites

In this study, we focused on the synergistic effect between carbon black (CB) and graphene nanoplatelets (GNPs) of various aspect ratios and specific surface areas as hybrid fillers in natural rubber (NR) nanocomposites. Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and scanning electron microscopy (SEM) were carried out to characterize the GNPs properties, while dynamic mechanical analysis (DMA), tensile properties, hardness, thermal conductivity, swelling behavior in toluene and SEM were performed on the NR nanocomposites. The results showed the positive effect of GNPs on the thermal and mechanical properties, which was attributed to the high surface area and aspect ratio of the GNPs playing a vital role in producing a conductive GNPs/CB hybrid fillers’ network. Among the three GNPs investigated, the sample having the highest lateral dimension (25 µm) led to a denser and more thermally conductive network. On the other hand, the GNPs/CB hybrid fillers’ synergy increased with increasing concentration inside the NR nanocomposites up to 5 phr due to their good dispersion as confirmed via SEM.