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采用分子动力学方法模拟了变截面微纳米通道内聚乙烯分子的注射过程,分析了微纳米通道截面结构及外加作用力对注射过程中聚乙烯分子流变和结构特性的影响.研究结果表明:注射流动过程中,通道壁面附近存在粒子吸附层,且吸附层厚度随通道锥面倾角增大而增大;聚乙烯分子链的注射距离随锥面倾角增大而减小、随外加作用力增大而增大;在锥面倾角为α=45°的通道中聚乙烯分子均匀填充整个通道,且沿流动方向上出现单轴拉伸现象,在较大作用力情况下,该拉伸更为显著,使得注射过程更容易完成.
Molecular dynamics simulation was used to simulate the injection process of polyethylene molecules in the micro-nanochannels. The effects of cross-sectional structure and applied force on the molecular rheology and structural properties of polyethylene during injection were analyzed. The results show that: In the process of injection, the particle adsorption layer exists near the wall of the channel and the thickness of the adsorption layer increases with the increase of the dip angle of the channel. The injection distance of the polyethylene molecular chain decreases with the increase of the cone angle. With the increase of the applied force Large and larger; in the channel with a cone angle of α = 45 °, the polyethylene molecules uniformly fill the entire channel and uniaxial stretching phenomenon occurs along the flow direction, and in the case of larger force, the stretching is more Significantly, making the injection process easier to accomplish.