Miscibility, morphology, thermal, and mechanical properties of a DGEBA based epoxy resin toughened with a liquid rubber
Miscibility, morphology, thermal, and mechanical properties of a DGEBA based epoxy resin toughened with a liquid rubber
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DOI：
10.1016/j.polymer.2007.11.030
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发表时间：
2008-01
期刊：
影响因子：
4.6
通讯作者：
Raju Thomas;Y. Ding;Yuelong He;Yang Le;P. Moldenaers;Wei-min Yang;T. Czigány;Sabu Thomas
中科院分区：
文献类型：
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作者：
Raju Thomas;Y. Ding;Yuelong He;Yang Le;P. Moldenaers;Wei-min Yang;T. Czigány;Sabu Thomas
使用酸酐固化剂固化基于双酚A的二缩水甘油醚和不同含量的端羟基聚丁二烯的环氧树脂。研究的最终目的是通过液体橡胶对脆性环氧树脂基体进行改性，以提高其韧性。对改性网络进行化学流变学分析，以了解固化聚合反应过程中发生的物理转变。胶凝时间的延迟可以通过稀释和粘度效应导致的较低反应性来解释。研究了纯网络和改性网络的拉伸、弯曲和断裂韧性行为，以观察橡胶改性的效果。通过扫描电子显微镜检查增韧网络的形态演变，观察结果被有效地用来解释具有不同含量的液体橡胶的网络的冲击性能。声发射研究进行了净和某些修改后的系统。根据声发射结果和形态特征，讨论了其增韧和失效机理。通过动态力学分析评价了弛豫峰的行为，并试图解释网络的组成。采用热重分析（TGA）研究了增韧环氧树脂的热稳定性。对纯环氧树脂和改性环氧树脂的分解活化能进行了估算和比较。已经证实并解释了改性后热固性材料的交联密度的降低。
Epoxy resin based on diglycidyl ether of bisphenol A and varying content of hydroxyl terminated polybutadiene were cured using an anhydride hardener. The ultimate aim of the study was to modify the brittle epoxy matrix by liquid rubber to improve the toughness characteristics. Chemorheological analysis of the modified network was performed to understand the physical transformations taking place during the cure polymerization reaction. The delay in gel time on inclusion of rubber can be explained by lower reactivity due to dilution and viscosity effect. Tensile, flexural, and fracture toughness behaviors of neat as well as modified networks have been studied to observe the effect of rubber modification. The morphological evolution of the toughened networks was examined by scanning electron microscope, and the observations were used effectively to explain the impact properties of the network having varying content of liquid rubber. Acoustic emission studies were performed on neat and certain modified systems. Based on acoustic emission results and morphological characteristics, toughening and failure mechanisms were discussed. The behavior of the relaxation peaks were evaluated by dynamic mechanical analysis and tried to explain the composition of networks. Thermal stabilities of the toughened epoxies were studied using thermogravimetric analysis (TGA). The activation energy for decomposition of neat and modified epoxies has been estimated and compared. The reduction in cross-linking density of the thermoset upon modification has been confirmed and explained.