干摩擦和水润滑条件下丁腈橡胶摩擦学性能的分子动力学研究

Molecular dynamics study of tribological properties ofnitrile butadiene rubber under dry friction and water lubrication

目的 探究丁腈橡胶(NBR)在干摩擦和水润滑条件下的微观润滑机理。方法 通过分子动力学(MD)模拟NBR在干摩擦和水润滑条件下的摩擦学性能。结果 水润滑条件下,NBR的摩擦系数和磨损率比干摩擦条件分别降低了75%和90%。这主要源于水分子在摩擦界面的作用,它不仅降低了界面温度(从331 K降至301 K),而且提高了原子浓度和速度(分别增加约49%和6倍)。此外,径向分布函数(RDF)、均方位移(MSD)和动能的模拟分析表明,水分子的加入削弱了对偶与NBR分子链之间的相互作用力,进而形成稳定的润滑膜。结论 润滑膜的形成是改善NBR摩擦学性能的根本原因。该研究从原子层面深入理解了润滑机理。

Purposes—To investigate the micro-lubrication mechanism of nitrile butadiene rubber(NBR)under dry friction and water lubrication.Methods—The tribological properties of NBR under dry friction and water lubrication are simulated by molecular dynamics(MD).Results—Compared with dry friction,the friction coefficient and wear rate of NBR under water lubrication are reduced by 75%and 90%respectively.This is mainly due to the action of water molecules at the friction interface,which not only reduces the interface temperature(from 331 K to 301 K),but also increases the atomic concentration and velocity(by about 49%and 6 times,respectively).In addition,through the simulation analysis of radial distribution function(RDF),mean square displacement(MSD)and kinetic energy,it is found that the interaction between the countpart and NBR molecular chains is weakened by the addition of water molecules,and a stable lubricating film is formed.Conclusions—The formation of lubricating film is the fundamental reason for improving the tribological properties of NBR.This research provides an in-depth understanding of the lubrication mechanism at the atomic level.