Thermal‐oxidative aging behavior of graphene and graphene oxide‐filled nitrile butadiene rubber: A molecular simulation approach

Abstract

Nitrile rubber (NBR) is commonly used as a stator rubber for screw pumps because of its excellent mechanical properties. However, under high‐temperature conditions, using NBR for long‐term operations is difficult, since it is highly susceptible to a thermal‐oxidative aging phenomenon that leads to its failure. In this study, the thermal‐oxidative aging behavior of graphene and graphene oxide (GO) in an NBR composite system was investigated using simulated molecular dynamics at 298 K and 348 K. The results showed that Young's moduli of graphene/NBR and GO/NBR composite systems were enhanced by about 33% and 44%, respectively, when the temperature was increased. That is, adding graphene and GO improved the resistance of NBR composites to elastic, bulk, and shear deformation, playing an important role in slowing down the thermal and oxygen aging of rubber. Furthermore, the binding energy, mean square displacement, and free volume fraction of the NBR composite systems were analyzed. The abundant oxygen‐containing functional groups in GO increased the intermolecular interaction force between GO and NBR and effectively inhibited the migration of antioxidants 4020. Therefore, GO retards the thermal and oxygen aging of NBR composite systems more effectively.

Accelerated aging behavior and degradation mechanism of nitrile rubber in thermal air and hydraulic oil environments

“…Nitrile rubber (NBR) is widely applied in the aviation industry as a dynamic or static sealant owing to its excellent resistance against oils and solvents, wear resistance, excellent processability, and good mechanical properties. [1][2][3][4][5][6][7] However, butadiene units, which possess massive unsaturated double bonds, accelerate the aging of NBR, especially at high temperatures or under ultraviolet light, mechanical loading, and an ozone atmosphere, [4,[8][9][10][11][12] all of which deteriorate its performance. It would be possible to predict the lifetime of NBR and make full use of its performance upon understanding its aging behavior, as well as degradation mechanism.…”