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采用分子动力学方法建立了二乙基甲苯二胺/双酚A缩水甘油醚环氧树脂体系(DETDA/DGEBA体系)和间苯二胺/双酚A缩水甘油醚环氧树脂体系(mPDA/DGEBA体系)的交联模型,在此基础上,分析了固化剂分子结构的差异对树脂性能的影响,研究发现mPDA/DGEBA体系的玻璃化转变温度、模量以及阻碍水分子的扩散性能均高于DETDA/DGEBA体系。为了进一步揭示交联环氧树脂分子结构与性能之间的关系,研究了上述两体系的自由体积和内聚能密度。结果表明,与DETDA/DGEBA体系相比,mPDA/DGEBA体系具有较小的自由体积和较高的内聚能密度。较小的自由体积和较高的内聚能密度是造成mPDA/DGEBA体系玻璃化转变温度、模量以及阻碍水分子的扩散性能均高于DETDA/DGEBA体系的原因。
Diethyl toluenediamine / bisphenol A glycidyl ether epoxy resin system (DETDA / DGEBA system) and m-phenylenediamine / bisphenol A glycidyl ether epoxy resin system (mPDA / DGEBA) were established by molecular dynamics method System), on the basis of which, the influence of the difference of the molecular structure of the curing agent on the properties of the resin was analyzed. It was found that the glass transition temperature and the modulus of the mPDA / DGEBA system and the diffusion resistance of the water molecules were all higher than DETDA / DGEBA system. In order to further reveal the relationship between molecular structure and properties of cross-linked epoxy resin, the free volume and cohesive energy density of the two systems were studied. The results show that the mPDA / DGEBA system has smaller free volume and higher cohesive energy density than DETDA / DGEBA system. The smaller free volume and higher cohesive energy density are the reasons that the glass transition temperature and the modulus of mPDA / DGEBA system and the barrier properties of water molecules are higher than that of DETDA / DGEBA system.