Comparative study on thermal-oxygen aging and tribological properties of carbon nanotubes and graphene sheet reinforced hydrogenated nitrile rubber composite materials

A comprehensive and comparative study of the thermal-oxygen aging and tribological properties of antioxidant 6PPD synergized with carbon nanotubes (CNTs) and graphene (GE)-reinforced hydrogenated nitrile rubber (HNBR) composites was performed using molecular simulations and experiments. The results indicated that GE exhibits superior capabilities in inhibiting the volatilization and migration of the antioxidant 6PPD compared to CNTs and enhancing the thermal and oxygen aging resistance of HNBR. The surface morphology of the HNBR composites was characterized using scanning electron microscopy (SEM) and X-ray spectroscopy (XPS), which revealed the different enhancement mechanisms of CNTs and GE. The mechanical and tribological properties of the HNBR composites were experimentally investigated before and after the thermal-oxygen aging. The results revealed that the tensile and tear strengths of the 6PPD/HNBR composites with added GE increased by approximately 4% compared to those of the 6PPD/HNBR composites with added CNTs. The coefficient of friction decreased by approximately 7%. Finally, the wear surface morphologies of the HNBR composites were characterized using SEM and energy dispersive spectrometer (EDS). These results further indicate that the larger specific surface area of GE can be better combined with HNBR, improving its overall thermal-oxygen aging and tribological properties.