热塑性聚合物热熔接过程界面扩散行为分子动力学模拟

采用分子动力学模拟方法对热塑性聚合物的热熔接过程界面扩散行为进行了研究,建立了具有两个层晶胞的聚甲基丙烯酸甲酯(PMMA)界面模型,采用等温等压(NPT)系综分别对不同温度及压力下界面间分子链扩散行为进行了模拟,计算了PMMA界面体系原子扩散系数、扩散层厚度及界面结合能,分析了温度、压力等因素对界面扩散行为的影响规律....

Molecular dynamic simulation of interface diffusion behavior during melting joining of thermoplastic polymer

Interfacial diffusion behavior during melting joining of thermoplastic polymer was studied using molecular dynamic simulation method.Two-layer cell interface comprising model for polymethyl-methacrylate(PMMA) was constructed.Under different temperatures and pressures,interfacial molecular chains motion was simulated using constant temperature and pressure(i.e.NPT) ensemble,diffusion coefficient of total atom of PMMA interface system,interfacial diffusion depth and binding energy were calculated,and influencing rule of factors such as temperature and pressure to interface diffusion behavior was analyzed.Simulated results show that by heating or pressing atoms diffusion speed was improved,interfacial diffusion depth was increased by higher pressure,more interfacial binding energy was gained by higher pressure.The simulation results agreed well with the macro hot-embossing experiments,and revealed the molecular diffusion behavior between PMMA interfaces during melting joining from molecular size.