摘要提高高分子聚合物导热性能的机理及实现途径的研究，对于既能有效导热、又能抗 腐蚀的特种高分子聚合物（如塑料）的研制，具有重要的理论意义与工程应用价值。分 子动力学模拟（Molecular Dynamics Simulation, 简称 MD 模拟）是物理化学过程机 理研究的重要工具，可观测到实验难以测得的微观结构及特征。因此，开展高分子聚合 物物理及传热性能的 MD 模拟研究，可更好地阐述高分子聚合物受应力形变和传热的机理， 为其变化过程的预测提供依据，对高分子聚合物物理性能的提高起到指导作用。79973

首先，本文利用化学反应动力学 ReaxFF 势进行全原子（all-atomic）模拟拟合获得 了高分子聚合物聚乙烯和聚丙烯的 Coarse-Grained 势场参数，并用 CG 势场模拟获得其 键长键角分布验证 CG 势参数，结果表明 CG 势场参数是准确的。

其次，开展了 300K 温度下聚乙烯高分子聚合物的 MD 模拟研究，研究了聚乙烯模块 的机械性能，探讨了 CG 势参数对材料物理性能的影响：基于所获得的 CG 力场，模拟计 算出聚乙烯模块拉伸时应力应变曲线，得到聚乙烯杨氏模量的值为 0。01GPa 左右，与实 际值相符；CG 势参数中 Lennard-Jones 势 ε 值为影响高分子聚合物模块物理性能的重要 参数，ε 值越大碳链间的作用力越大，计算获得的杨氏模量值也越大，相变温度也随之 提高。

最后，我们采用 Müller-Plathe 方法研究了无序聚乙烯模块的传热性能，得到其导 热系数为 0。1396 W/(m·K)，与实际物性参数值（0。1~0。5W/(m·K)）近似。我们还进一 步研究了拉伸应变对聚乙烯传热性能的影响，研究表明材料热导率随材料应变的增加而 增大，在应变为 8 时，其热导率增大到约 6。6 倍，得到了显著的提高。

毕业论文关键词 高分子聚合物 分子动力学模拟 导热性能 机械性能 Coarse-Grained 力场

毕 业 设 计 说 明 书 外 文 摘 要

Title Molecular simulation studies of thermal conductivity of polymer materials

Abstract Improving the mechanism research of thermal conductivity of polymer research and implementation approaches have important theoretical significance and application value in development of specialty polymers which not only have the effective thermal conductivity, but also have corrosion resistance(such as plastic) 。

Molecular dynamics simulation (referred to as the MD simulation) is an important tool to study the mechanism of physical and chemical processes and can observe microstructural features and difficult experiment measured。Therefore, MD simulation study conducted polymer physical properties and heat transfer performance can be better in explaining the nature of polymer deformation and heat stress, and provides the basis for forecasting the process of change, and plays a guiding role in improving the physical properties of polymers。

Firstly, using of molecular dynamics simulation method, comparated with chemical reaction kinetics ReaxFF all-atomic simulation , this paper establishes a coarse-grained model potential field parameters and polymers polyethylene and polypropylene, and analyze their bond lengths and angular distribution, then verives CG potential parameters。

Secondly, it carried out MD simulation of polyethylene polymer at a temperature of 300K, and studied the mechanical properties and thermal properties of polyethylene module, it discussed the influence of CG parameter for physical properties of materials。 Based on the obtained CG Field , when polyethylene module stretching were simulated , throngh the stress-strain curve ,we obtained Young's modulus polyethylene is about 0。01 GPa, consistent with the actual value; CG potential parameters of Lennard-Jones potential ε is the main parameters