This paper investigated the mechanism of enhancing the mechanical and tribological properties of nitrile rubber (NBR) via the addition of nano-SiO₂ on the molecular scale. Molecular dynamics (MD) simulations were performed on molecular structure models of pure NBR, NBR/SiO₂, and three-layer friction pairs. The results showed that the hydrogen bonds and interfacial interaction between nano-SiO₂ and NBR molecular chains decreased the fractional free volume of NBR nanocomposites and increased the shear modulus of NBR by 25% compared with that of pure NBR. During the friction process, nano-SiO₂ decreased the radius of gyration of NBR molecular chains and effectively lowered the peak atomic velocity, the peak temperature, and the peak friction stress at the interface between NBR and copper atoms. The average friction stress on NBR/SiO₂ was 34% lower than that on NBR, which meant the tribological properties of NBR were significantly improved by nano-SiO₂. The mechanism of nano-SiO₂-reinforcing NBR on a molecular scale can lay a theoretical foundation for the design of water-lubricated rubber bearings.

本文研究了通过在分子尺度上添加纳米SiO ₂来增强丁腈橡胶（NBR）的机械和摩擦学性能的机理。在纯NBR，NBR / SiO ₂和三层摩擦对的分子结构模型上进行了分子动力学（MD）模拟。结果表明，与纯NBR相比，纳米SiO ₂和NBR分子链之间的氢键和界面相互作用降低了NBR纳米复合材料的自由体积分数，并使NBR的剪切模量提高了25％。在摩擦过程中，纳米SiO ₂减小了NBR分子链的回转半径，并有效降低了NBR与铜原子之间界面的峰值原子速度，峰值温度和峰值摩擦应力。NBR / SiO ₂的平均摩擦应力比NBR的平均摩擦应力低34％，这意味着纳米SiO _2可以显着改善NBR的摩擦学性能。分子尺度上的纳米SiO ₂增强丁腈橡胶的机理可以为水润滑橡胶轴承的设计奠定理论基础。