改性石墨烯增强聚四氟乙烯摩擦学性能的分子模拟研究  

Molecular Dynamics Simulation on the Tribological Properties of Polytetrafluoroethylene Reinforced with Modified Graphene

作　　者：尹宇航 雷浩 宋敬伏[1] 赵盖[1,2] 丁庆军[1] YIN Yuhang;LEI Hao;SONG Jingfu;ZHAO Gai;DING Qingjun(State Key Laboratory of Mechanics and Control of Mechanical Structures,Nanjing University of Aeronautics and Astronautics,Jiangsu Nanjing 210016,China;State Key Laboratory of Solid Lubrication,Lanzhou Institute of Chemical Physics,Chinese Academy of Sciences,Gansu Lanzhou 730000 China)

机构地区：[1]南京航空航天大学机械结构力学与控制国家重点实验室,江苏南京210016 [2]中国科学院兰州化学物理研究所固体润滑国家重点实验室,甘肃兰州730000

出　　处：《摩擦学学报》2022年第3期598-608,共11页Tribology

基　　金：国家自然科学基金项目(52075247,U2037603)资助。

摘　　要：采用分子动力学模拟研究了接枝改性氧化石墨烯对聚四氟乙烯(PTFE)的增强作用与摩擦学性能的影响,首先选用KH550、KH560和KH570三种硅烷偶联剂接枝氧化石墨烯(GO),在填入纯聚四氟乙烯后计算其机械性能与摩擦性能.对比得出KH560的增强效果最好,杨氏模量和剪切模量分别提高了205%和116%,摩擦系数提高了39.6%.然后选用聚酰亚胺(PI)接枝氧化石墨烯,对比了接枝改性与物理共混两种方式对增强效果的影响,结果表明接枝改性的增强效果优于物理共混.最后通过分析界面间相互作用力、结合能、原子相对浓度和原子运动速度等方式揭示了接枝氧化石墨烯对聚四氟乙烯基体的增强机理.Improving the performance of polytetrafluoroethylene(PTFE)becomes a popular research area,which plays an important role on the actual application in the aerospace,machinery,chemical industry field,and so on.The common enhancement methods for polymer are filling fibers,nanosheets and micro-nano particles.However,the reinforced mechanism has not been fully understood,especially under an atomic level due to experimental measurement limitation.In this study,we employed a molecular dynamics(MD)simulation to study the tribological properties of PTFE reinforced by modified graphene with excellent mechanical strength in order to explore the reinforced mechanism from a molecular view.Firstly,graphene oxidation(GO),as a reinforced filler,was grafted by three different silane coupling agents,KH550,KH560 and KH570,to improve the interfacial compatibility with PTFE matrix,respectively.The calculation results indicated that PTFE composites filled by KH560-GO had the highest Young’s modulus and shear modulus,which was increased by 205%and 116%,respectively.Then,the frictional model of PTFE composites sliding against copper based on the contact of ultrasonic motors was built and the tribological properties was evaluated.The simulated results showed that the friction coefficient of PTFE was increased by 39.6%after filling the KH560-GO.The shear deformation was also greatly reduced after filling GO modified by silane coupling agents.Besides,the polyimide(PI)with high rigidity was selected to modify GO to further improve the mechanical strength of PTFE.The ungrafted GO and single PI molecular were also filled in the PTFE matrix to compare the effect of modification.It was obviously found that the PI grafted GO had the higher Young’s modulus and shear modulus than that just filling GO blended with single PI molecular,increased by 71.2%and 56.9%,respectively.Finally,the reinforcement mechanism was systematically analyzed by observing the dynamic evolution of whole shear process and extracting the variation information of the inte

关 键 词：聚四氟乙烯 改性石墨烯 摩擦学 分子模拟 

分 类 号：TB332[一般工业技术—材料科学与工程]