Mechanical and Thermal Properties of Epoxy Resin Modified with Polyurethane
Mechanical and Thermal Properties of Epoxy Resin Modified with Polyurethane
复制标题
DOI：
10.1177/0731684408091703
复制
发表时间：
2009-09-01
影响因子：
3.1
通讯作者：
Kostrzewa, M.
中科院分区：
文献类型：
--
作者：
Bakar, M.;Duk, R.;Kostrzewa, M.
采用不同异氰酸酯指数的聚氨酯对环氧树脂进行改性。将冲击强度、拉伸强度、断裂伸长率和弯曲强度估计为聚氨酯含量和异氰酸酯指数的函数。对所选组合物的硬度、线性膨胀系数和负载变形温度进行了评估。对未改性的环氧树脂和具有改进的机械性能的组合物进行了红外光谱分析。异氰酸酯含量最高的聚氨酯可最大程度地提高断裂韧性。硬度不受影响，但弹性模量降低，这意味着环氧基组合物软化。红外光谱表明，过量的异氰酸酯基团导致改性剂和基体之间发生接枝过程，解释了后者的增韧。
Epoxy resin was modified with polyurethane having different isocyanate index. Impact strength, tensile strength, elongation at break and flexural strength were estimated as functions of polyurethane content and isocyanate index. Hardness, linear expansion coefficient and the deflection temperature under load were estimated for selected compositions. Infrared spectroscopy was carried out for unmodified epoxy resin and compositions with improved mechanical properties. Maximum improvement in the fracture toughness was reached with polyurethane with highest content of isocyanate. Hardness was not affected but elastic modulus decreased, implying a softening of epoxy-based compositions. The infrared spectra indicated that an excess of isocyanate groups leads to a grafting process between the modifier and the matrix, explaining the toughening of the latter.