Thermal‐oxidative aging and tribological properties of carbon nanotube/nitrile butadiene rubber composites with varying acrylonitrile content: Molecular dynamics simulations

Abstract

AbstractNitrile butadiene rubber (NBR), a common material used in the stator rubber of screw pumps, usually undergoes severe thermal‐oxidative aging and wear at various temperatures and pressures. In this study, 1,2‐dihydro‐2,2,4‐trimethylquinoline (antioxidant RD) and carbon nanotubes (CNTs) were introduced into NBR to improve its thermal‐oxidative aging performance and reduce its wear. The thermal‐oxidative aging and mechanical and tribological properties of NBR composites with acrylonitrile (ACN) contents of 28%, 33%, and 41% were investigated via molecular dynamics simulations, and the interaction mechanisms of four composites: RD/N28, CNT/RD/N28, CNT/RD/N33, and CNT/RD/N41, were investigated at the atomic level. A three‐layer model (Fe–Composites–Fe) was developed to simulate the wear process of the composites. CNT/RD/N41 exhibited better thermal‐oxidative aging and tribological properties than those exhibited by CNT/RD/N28 and CNT/RD/N33. This was attributed to an increase in the polar–polar interactions of the nitrile (CN) groups with an increasing ACN content. During friction, a larger frictional force existed between the CNT/RD/N41 molecules, which effectively maintained the stability of the matrix. This study provides a scientific reference for the preparation of high‐performance NBR at the microscopic scale, which may extend the service life of screw pumps.