纳米二氧化锆增强丁腈橡胶力学性能的分子动力学模拟

采用分子动力学模拟的方法建立了纳米二氧化锆增强丁腈橡胶（NBR）复合材料的分子模型，对比分析了外部填充、原位填充以及原位填充且经过偶联化处理三种形态的二氧化锆对NBR力学性能的增强效果，从原子层面探讨了定子橡胶力学性能的内在增强机制。结果表明，相比于纯NBR，三种形态二氧化锆的引入均显著改善了NBR的力学性能。原位填充纳米二氧化锆的表面羟基与NBR形成氢键型偶极相互作用，表面活性偶联剂双-（3-三乙氧基硅烷丙基）四硫化物的加入进一步提供了与橡胶基质之间的化学桥接，从而大大提升了NBR基质的力学性能。与纯NBR体系相比，原位填充且经过偶联化处理的二氧化锆增强NBR的力学性能表现最佳，复合体系的杨氏模量、体积模量和剪切模量均提升得最多。通过界面结合能、非键合能、均方位移和扩散系数的计算，验证了纳米二氧化锆的添加改善了定子橡胶力学性能的结论。

Molecular dynamics simulation of reinforcement of mechanical properties of nitrile rubber by adding nano-zirconia

The molecular model of nano-zirconia reinforced nitrile rubber （NBR） composite was established by molecular dynamics simulation. The reinforcement effects of three forms of nano-zirconia, namely, external filling, in-situ filling, and in-situ filling and coupling treatment on mechanical pro-perties of NBR were compared and analyzed, internal reinforcement mechanism of the mechanical properties of stator rubber was discussed from atomic level. The results showed that compared with pure NBR, the mechanical properties of NBR were significantly improved by introduction of three forms of nano-zirconia. The surface hydroxyl of in-situ filled nano-zirconia interacted with NBR to form hydrogen bond type dipole interaction. The addition of surfactant coupling agent bis-（3-triethoxysilane propyl） tetrasulfide further provided a chemical bridge with the rubber matrix, thus greatly improving the mechanical properties of NBR matrix. Compared with pure NBR system, the nano-zirconia filled in situ and treated by coupling had the best performance in enhancing the mechanical properties of NBR, and the young’s mo-dulus, volume modulus and shear modulus of the composite system were improved the most. The conclusion that the addition of nano-zirconia improved the mechanical properties of stator rubber was verified by calculating the interface binding energy, non-bond energy, mean square displacement and diffusion coefficients.