High-performance styrene-butadiene rubber nanocomposites based on carbon nanotube/nanodiamond hybrid with synergistic thermal conduction characteristics and electrically insulating properties

Reinforcement of rubbery materials with carbon nanotube (CNT) has gained much attention over the last few decades due to the inherent ability of CNT to improve the physical and mechanical properties of polymer composites. However, CNT renders electrical conductivity to the rubber composites, which could be problematic for a number of applications. In an attempt to overcome such issues, we controlled the insulating properties of styrene-butadiene rubber (SBR) nanocomposites by hybridization of CNT with nanodiamond (ND) particles without scarifying desirable features of the nanoparticles. In this respect, the effects of carbon nanotube (CNT) and nanodiamond (ND), either individually or in hybrid form, on mechanical, physical, morphological and thermal properties of styrene-butadiene rubber (SBR) nanocomposites were well characterized in the present research using bound rubber, tensile, dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), electrical, and thermal conductivity characterizations. The SBR nanocomposites holding nanoparticle concentrations ranging from 1 to 5 phr were fabricated at various CNT/ND compositions. The results indicated that the hybridization of nanoparticles improved the dispersion state of individual nanoparticles in SBR, successfully controlled the insulating behavior of the SBR nanocomposite and enhanced the thermal conductivity of SBR in synergistic manner; while the mechanical improvement retained as CNT filled SBR. The SBR nanocomposites holding 5 phr hybrid-nanoparticles with appropriate nanoparticles composition possessed thermal conductivity more than two-fold of unfilled SBR and 20% more than nanocomposite with 5 phr loading of single CNT.