Molecular dynamics investigation on the thermal-oxidative aging and mechanical properties of nitrile butadiene rubber composites with molybdenum disulfide

Rubber has a wide range of application prospects as an important material in the field of oil extraction and sealing rings. The effect of molybdenum disulfide (2H-MoS₂) on the properties of the composites of antioxidant 4020 and nitrile butadiene rubber (NBR) was investigated. Two sets of composites, 4020/NBR and MoS₂/4020/NBR, were modeled using molecular dynamics simulations. The mechanical, thermal-oxidative aging and tribological properties of 2H-MoS₂ on NBR composites were investigated at 298 and 398 K, respectively, and the adsorption ability and reinforcement effect of 2H-MoS₂ on NBR were analyzed from an atomic perspective. The mechanical studies showed that Young’s modulus of MoS₂/4020/NBR composites was improved by about 28% and 23% compared with 4020/NBR composites at 298 and 398 K temperatures, respectively. Therefore, the mechanical properties of NBR composites were significantly improved by the addition of MoS₂. Similarly, the properties such as solubility parameters, mean square displacement, and binding energy of MoS₂/4020/NBR composites were improved, and the stability and thermal and oxygen aging properties of NBR composites were effectively improved after the addition of MoS₂. Tribological studies also showed that the friction coefficients of MoS₂/4020/NBR composites were reduced by about 30% and 25%, and the wear rates were reduced by 5% and 7% at 298 and 398 K, respectively, compared with those of 4020/NBR composites. Therefore, MoS₂ successfully enhances the tribological characteristics of NBR composites.