Friction properties of graphene reinforced nitrile rubber composites after thermal oxidation aging: Experiment and molecular dynamics simulation

We established friction models for pure NBR, GNS/NBR, and GO/NBR composites through molecular dynamics (MD) simulation. Our study focused on the impact of GNS and GO on the friction properties of nitrile rubber (NBR) composite materials after undergoing thermal oxygen aging. Based on the simulation results, it can be observed that the GNS/NBR and GO/NBR composites' coefficient of friction (COF) decreases by 20.8% and 24.8%, respectively, at 348 K. Additionally, the abrasion rate is reduced by 17.4% and 25.7%, respectively, for the same composites. Adding GNS and GO can effectively improve the friction performance of the NBR composite system, and compared with GNS, GO shows a better enhancement effect. Pure NBR and GO/NBR composite materials were prepared by mechanical blending method, and the friction properties of GO-enhanced NBR composite materials were studied. The experimental results show that the GO/NBR composite material can maintain a low friction and wear coefficient after thermal and oxygen aging. It shows that adding GO can effectively improve the friction properties of NBR composite systems and slow down the weakening effect of aging on the friction properties of NBR composite materials. This is because the GO surface contains wealthy functional groups such as epoxy groups, which enhances the binding strength between the GO and NBR interface so that the GO/NBR composite material exhibits better friction properties and thermal oxygen aging resistance. In addition, the wear surface was characterized by scanning electron microscopy (SEM), revealing the damage mechanism of friction and wear of NBR composite materials.