标题： 环氧树脂组成对交联热固性材料热性能和网络结构的影响：分子动力学研究 显示英文标题

标题： Effects of Epoxy Composition on the Thermal and Network Properties of Crosslinked Thermosets: A Molecular-Dynamics Study

摘要： 在本研究中，我们使用分子动力学模拟研究了树脂组成对交联环氧网络的热性和结构性能的影响。 所研究的体系基于双酚A二缩水甘油醚（DGEBA）和丁基化环氧树脂（BER）的混合物，以二乙基甲苯二胺（DETDA）作为固化剂。 使用多步骤交联算法生成高度交联的网络。 我们系统地探讨了添加BER如何影响最终热固性材料的网络拓扑结构和热物理行为。 我们的结果表明，增加BER含量会导致网络逐渐松散，这由更长的氮原子间路径长度和更大的Voronoi原子体积所证明。 这种结构松散导致热膨胀系数（CTE）更高、原子移动性更强以及玻璃化转变温度降低。 为了量化局部立体效应和拓扑效应，我们引入了一个约束指数，该指数能够捕捉原子层面的拥挤程度和连接性。 该指数与观察到的玻璃化转变温度趋势有很强的相关性，表明其作为聚合物网络行为预测描述符的潜力。 我们的研究结果提供了关于环氧树脂组成如何调节网络结构和热机械性能的分子级见解。 显示英文摘要

摘要： In this study, we investigate the influence of resin composition on the thermal and structural properties of crosslinked epoxy networks using molecular-dynamics simulations. The systems studied are based on mixtures of diglycidyl ether of bisphenol A (DGEBA) and butylated epoxy resin (BER), cured with diethyltoluenediamine (DETDA). A multi-step crosslinking algorithm was used to generate highly crosslinked networks. We systematically explored how the addition of BER affects the network topology and thermophysical behavior of the resulting thermosets. Our results show that increasing BER content leads to a progressive loosening of the network, evidenced by longer inter-nitrogen path lengths and larger Voronoi atomic volumes. This structural loosening results in a higher coefficient of thermal expansion (CTE) and higher atomic mobility as well as a reduction in the glass-transition temperature. To quantify local steric and topological effects, we introduce a confinement index that captures atomic-level crowding and connectivity. The index shows a strong correlation with the observed trend in glass-transition temperature, suggesting its potential as a predictive descriptor for polymer network behavior. Our findings provide molecular-level insights into how epoxy resin composition modulates network structure and thermomechanical properties.