高等学校化学学报 ›› 2018, Vol. 39 ›› Issue (12): 2693-2699.doi: 10.7503/cjcu20180626

• 物理化学 • 上一篇    下一篇

高分子熔体的空间密度关联

潘登1,2, 孙昭艳1,2,3()   

  1. 1. 中国科学院长春应用化学研究所, 高分子物理与化学国家重点实验室, 长春 130022
    2. 中国科学院大学, 北京 100039
    3. 伊犁师范学院物理科学与技术学院, 新疆凝聚态相变与微结构实验室, 伊宁 835000
  • 收稿日期:2018-09-10 出版日期:2018-12-03 发布日期:2018-11-05
  • 作者简介:

    联系人简介: 孙昭艳, 女, 博士, 研究员, 博士生导师, 主要从事高分子物理研究. E-mail: zysun@ciac. ac. cn

  • 基金资助:
    国家自然科学基金(批准号: 21833008, 21474111, 21790340)和中国科学院前沿科学重点研究项目(批准号: QYZDY-SSW-SLH027)资助.

Spatial Density Correlation in Polymer Melts

PAN Deng1,2, SUN Zhaoyan1,2,3,*()   

  1. 1. State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry,Chinese Academy of Sciences, Changchun 130022, China
    2. University of Chinese Academy of Sciences, Beijing 100039, China
    3. Xinjiang Laboratory of Phase Transitions and Microstructures in Condensed Matters,College of Physical Science and Technology, Yili Normal University, Yining 835000, China
  • Received:2018-09-10 Online:2018-12-03 Published:2018-11-05
  • Contact: SUN Zhaoyan E-mail:zysun@ciac. ac. cn
  • Supported by:
    † Supported by the National Natural Science Foundation of China(Nos.21833008, 21474111, 21790340) and the Key Research Program of Frontier Sciences, Chinese Academy of Sciences, China(No.QYZDY-SSW-SLH027).

摘要:

利用分子动力学模拟方法, 以不同链结构的高分子熔体为对象, 研究了高分子熔体的空间密度关联. 链节的局域结构性质通过Voronoi分割方法得到. 结果表明, 链端链节的平均局域体积更大, 运动能力也更强; 不同构造及链不同部位链节的局域体积大小具有统一的分布规律, 表明在链节尺度上, 熔体具有相似的无定形结构. 通过局域体积来划分疏堆积和密堆积链节, 2种链节均倾向于形成团簇. 疏堆积链节形成的团簇更大, 并且团簇大小的温度依赖性也更显著. 模拟结果表明疏堆积链节的空间关联更强.

关键词: 空间密度关联, 高分子玻璃前体, 分子动力学模拟

Abstract:

The spatial density correlation in glass-forming polymer melt with different chain architectures was investigated using molecular dynamics simulation. The local environment of each bead was identified. Using the Voronoi construction, the results indicate that the chain ends have more local volume in the average level and the mobility of chain ends is higher. Moreover, the distributions of local volume become narrow when decreasing temperature and the rescaled distributions follow a master curve, implying that the melts have qualitatively similar amorphous structure for different chain architectures. The loosely and densely packed particles were identified according to their local volume. Both loosely and densely packed particles tend to form clusters, and the loosely packed particles was larger than that by densely packed particles. The simulation results demonstrate the spatial correlation of loosely packed particles is stronger, which might help to understand the glass forming behavior of polymer melts.

Key words: Spatial density correlation, Glass-forming polymer melt, Molecular dynamics simulation

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