Yang Jin, Weng Can, Lai Jun, Ding Tao, Wang Hao
College of Mechanical and Electrical Engineering, Central South University, Changsha 410083, China.
State Key Laboratory of High Performance Complex Manufacturing, Central South University, Changsha 410083, China.
Polymers (Basel). 2019 Sep 27;11(10):1573. doi: 10.3390/polym11101573.
In micro-injection molding, the interaction between the polymer and the mold insert has an important effect on demolding quality of nanostructure. An all-atom molecular dynamics simulation method was performed to study the effect of nanostructure shape, interfacial adhesion energy, and mold insert material on demolding quality of nanostructures. The deformation behaviors of nanostructures were analyzed by calculating the non-bonded interaction energies, the density distributions, the radii of gyration, the potential energies, and the snapshots of the demolding stage. The nanostructure shape had a direct impact on demolding quality. When the contact areas were the same, the nanostructure shape did not affect the non-bonded interaction energy at PP-Ni interface. During the demolding process, the radii of gyration of molecular chains were greatly increased, and the overall density was decreased significantly. After assuming that the mold insert surface was coated with an anti-stick coating, the surface burrs, the necking, and the stretching of nanostructures were significantly reduced after demolding. The deformation of nanostructures in the Ni and Cu mold inserts were more serious than that of the AlO and Si mold inserts. In general, this study would provide theoretical guidance for the design of nanostructure shape and the selection of mold insert material.
在微注塑成型中，聚合物与模具镶件之间的相互作用对纳米结构的脱模质量有重要影响。采用全原子分子动力学模拟方法研究了纳米结构形状、界面粘附能和模具镶件材料对纳米结构脱模质量的影响。通过计算非键相互作用能、密度分布、回转半径、势能以及脱模阶段的快照来分析纳米结构的变形行为。纳米结构形状对脱模质量有直接影响。当接触面积相同时，纳米结构形状对PP-Ni界面处的非键相互作用能没有影响。在脱模过程中，分子链的回转半径大幅增加，整体密度显著降低。假设模具镶件表面涂覆有防粘涂层后，脱模后纳米结构的表面毛刺、颈缩和拉伸现象明显减少。纳米结构在镍和铜模具镶件中的变形比氧化铝和硅模具镶件中的更严重。总体而言，本研究将为纳米结构形状设计和模具镶件材料选择提供理论指导。
