Molecular dynamics study on the effect of molecular orientation on polymer welding
Molecular dynamics study on the effect of molecular orientation on polymer welding
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DOI：
10.1016/j.polymer.2012.07.042
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发表时间：
2012-08
期刊：
影响因子：
4.6
通讯作者：
Katsuyuki Yokomizo;Yoshihiro Banno;M. Kotaki
中科院分区：
文献类型：
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作者：
Katsuyuki Yokomizo;Yoshihiro Banno;M. Kotaki
采用粗粒化分子动力学方法模拟了珠弹簧模型中两股平行流动的聚合物流动前沿的相互扩散过程。模拟了流动前沿分子取向对界面结构的影响。结果表明，对于长度大于缠结长度的链，剪切流动抑制了界面厚度随时间的演化。通过对端-端矢量自相关函数的分析，揭示了链的各向异性运动是导致界面厚度增长的主要原因，链取向弛豫是剪切流动影响界面厚度增长的重要机制。通过对扩散过程中末端珠粒和中心珠粒的密度分布进行分析，发现末端珠粒的相互扩散总是比中心珠粒快，并且在定向长链中受到明显抑制。
Coarse-grained molecular dynamics simulation of a bead-spring polymer model was conducted for interdiffusion of two polymer flow fronts flowing parallel to one another as would be found in a weld-line. The effect of molecular orientation of the flow fronts on the interfacial structure was simulated. It was observed that the time evolution of the interfacial thickness was suppressed by shear flow for a chain whose length was longer than entanglement length. According to the analysis of autocorrelation function of end-to-end vector, it was revealed that anisotropic motion of chain was responsible for the growth of interfacial thickness and relaxation of the chain orientation was an important mechanism to explain the effect of shear flow on the growth of interfacial thickness. From the analysis of the segment motion at the interface with taking the density profile of end beads and center beads during the diffusion, it was found that interdiffusion of the end segment was always faster than that of center segments and significantly suppressed in oriented long chain.