Surface modification of MWCNT to improve the mechanical and thermal properties of natural rubber nanocomposites

In this study, we focused on the synergistic effect between carbon black (CB) and multiwall carbon nanotube (MWCNT) hybrid fillers. In particular, the surface modification of pristine MWCNT (P‐MWCNT) via an acid (oxidation) treatment was used to improve their dispersion, as well as the mechanical and thermal properties of their corresponding natural rubber (NR)‐based nanocomposites. Fourier‐transform infrared spectroscopy (FTIR), X‐ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) were carried out to determine the presence of functional groups on the oxidized MWCNT (O‐MWCNT). After vulcanization, dynamic mechanical analysis (DMA), tensile properties, hardness, thermal conductivity, swelling behaviour in toluene and SEM characterizations were performed on both NR/CB/P‐MWCNT‐ and NR/CB/O‐MWCNT‐based nanocomposites. The results showed the positive effect of MWCNT surface oxidation on the fillers' dispersion and nanocomposites' properties.