环氧树脂热氧损伤的分子动力学模拟

Molecular Dynamics Modeling of the Thermo-oxidative Degradation in Epoxy Resin

采用分子动力学方法构建了不同交联程度的二乙醇胺/双酚A缩水甘油醚环氧树脂体系(DEA/DGEBA)及氧化断裂损伤的交联DEA/DGEBA模型。在此基础上,分析了交联程度和氧化程度对DEA/DGEBA体系的玻璃态转变温度和模量的影响,并对交联度、氧化程度耦合的DEA/DGEBA环氧树脂的玻璃态转变温度和力学性能进行了正交模拟和极差分析。结果表明在较高的交联度下,氧化程度对DEA/DGEBA体系力学性能影响强于交联度,而对于玻璃态转变温度的影响则与之相反。该模拟结果能准确匹配DEA/DGEBA环氧树脂固化实验的测量结果,并对热氧老化实验起到较好的支撑。

The models of diglycidyl ether of bisphenol A(DGEBA) epoxy with diethanolamine(DEA) and thermo-oxidative aging DEA/DGEBA were built via the combined method of molecular dynamic methods and perl script. The effect of oxidation degree and crosslinking degree on glass transition temperature(Tg) and modulus of epoxy resins were studied by orthogonal experiment and range analysis. The simulation results show that under the condition of a higher degree of crosslinking, the degree of oxidation has a stronger effect on the mechanical properties of DEA/DGEBA system than the degree of crosslinking, while the effect on the glass transition temperature is opposite. The results are consistent with the curing experiments. These results could be used to understand the usual modulus curve that first increased and then decreased found on thermo-oxidative aging experiment for DEA/DGEBA.