DGEBA/DCPDE双交联环氧树脂热机械性能的分子动力学模拟

Molecular Dynamics Simulation of Thermomechanical Properties of DGEBA/DCPDE Double-Crosslinked Epoxy Resin

研究材料宏观性能与微观结构的关系对于设计高性能环氧树脂绝缘材料具有重要意义。为此基于共混改性方法提高聚合物材料性能的基础,提出了双交联网络分子模型构建方法,以期望获得综合性能较好的环氧树脂绝缘材料。采用分子动力学(MD)模拟结合实验验证的方法,验证了双交联模型的准确性,研究了DGEBA/DCPDE双交联环氧树脂摩尔配比对其热机械性能的影响以及其微观结构与宏观性能的关联关系。结果表明:当DGEBA与DCPDE的摩尔配比为7:3时,双交联环氧树脂的整体性能较好;DCPDE/MA体系的引入,使得体系的自由体积占比(FFV)和均方位移(MSD)减小,分子链段运动能力减弱,弹性模量升高;FFV、MSD、非键能和二面角扭转能随温度的变化可用于预测交联体系的玻璃化转化温度(Tg)。

It is of great significance to explore the relationship between the macro-performance and micro-structure of materials for design of high-performance epoxy resin insulation materials.In this paper,based on the improvement of polymer properties by blending modification,a method of building molecular model of double-crosslinked network is proposed in order to obtain cross-linked epoxy resin insulation materials with better comprehensive properties.Molecular dynamics(MD)simulation and experimental validation were used to verify the accuracy of the double-crosslinked simulation model.The effects of the ratio of DGEBA/DCPDE double-crosslinked epoxy resin on its thermodynamic properties and the relationship between its microstructure and macroscopic properties were studied.The results show that when the ratio of DGEBA to DCPDE is 7:3,the overall performance of the double-crosslinked epoxy resin is better;the introduction of DCPDE/MA system decreases the fraction free volume(FFV)and mean square displacement(MSD)of the system,decreases the mobility of molecular segments,and increases the modulus of elasticity;the changes of FFV,MSD,non-bonding energy,and twist energy of dihedral angle with temperature can be used to predict the glass transition temperature(Tg)of the cross-linked system.