碳纳米管直径对丁腈橡胶复合材料性能影响的分子模拟

利用分子动力学模拟研究碳纳米管(CNTs)直径改变时对丁腈橡胶(NBR)基体力学及摩擦学性能的影响。采用恒应变法考察不同复合材料模型的力学性能，结果表明复合材料力学性能随着NBR基体中CNTs直径增大呈现先增加后减小的趋势。剪切模拟结果表明，剪切后复合材料基体中分子链发生了不同程度的断裂，出现了聚合物分子链向摩擦界面聚集的现象，其中较大直径CNTs增强NBR复合材料中分子链相对完整连续，摩擦学性能改善效果更好。较大直径CNTs对NBR基体具有显著的增强效果，限制了NBR分子链的活动能力，更多的分子链聚集在CNTs周围，复合材料体系致密性及稳定性提高，从而改善了CNTs/NBR复合材料力学及摩擦学性能。其中直径(6,6)CNTs增强NBR复合材料具有更高的剪切模量，力学性能优异，表现出了更好的摩擦磨损性能。

Molecular Simulation of the Effect of Carbon Nanotube Diameter on the Properties of Nitrile-Butadiene Rubber Composites

The effect of the diameter of carbon nanotubes(CNTs)on the mechanical and tribological properties of nitrile-butadiene rubber(NBR)matrix was studied by molecular dynamics simulation.The mechanical properties of different composite models were investigated by constant strain method.The results show that the mechanical properties of the composites increase first and then decrease with the increase of the diameter of CNTs in NBR matrix.The shear simulation results show that the molecular chains in the matrix of the composites are broken to varying degrees after shearing,and the polymer molecular chains are aggregated to the friction interface.The molecular chains in the larger diameter CNTs reinforced NBR composites are relatively complete and continuous,resulting in better improvement of tribological properties.The larger diameter CNTs have a significant reinforcing effect on the NBR matrix,which limits the mobility of the NBR molecular chain.More molecular chains gather around CNTs,and the density and stability of the composite system are improved,thereby improving the mechanical and tribological properties of the CNTs/NBR composites.The diameter(6,6)CNTs reinforced NBR composites have higher shear modulus,excellent mechanical properties,and better friction and wear properties.