【摘要】 采用环氧树脂 (E 5 1)与氰酸酯树脂共聚以改善氰酸酯树脂的韧性 ,研究了环氧树脂的加入量、后处理温度、湿热老化以及紫外光老化等条件对改性后树脂体系力学性能的影响规律 ,采用扫描电子显微镜对断口形貌进行了分析。结果表明环氧树脂可以明显改善氰酸酯树脂的韧性 ,环氧树脂含量为 3 0 % (质量百分数 ,下同 )的体系的冲击强度和弯曲强度分别比改性前提高了 10 0 %和 5 0 %。随环氧树脂用量的增加 ,改性树脂的冲击强度和弯曲强度提高 ,树脂表现为明显的韧性断裂 ;改性体系经 2 0 0℃后处理 2h的力学性能最佳 ;湿热老化和紫外光老化都使改性树脂体系的冲击强度和弯曲强度降低 ,而后者的影响较弱 ,当环氧树脂用量低于 3 0 %时冲击强度和弯曲强度的保持率均高于 95 %。更多还原

【Abstract】 Epoxy resin(E-51)was used to improve mechanical properties of cyanate ester resin by copolymerization with bisphenol A dicyanate ester. The influence of epoxy resin concentration, post cure temperature, hydrothermal aging and ultraviolet radiation aging on mechanical properties of the modified system was studied. Fracture surfaces of broken specimens were examined by scanning microscopy. The modified system showed much higher fracture toughness. Inclusion of 30 % epoxy resin led to 100 % and 50 % increase in impact strength and flexural strength, respectively. The impact strength and flexural strength were found to rise with increasing concentration of epoxy resin, and modified resin system exhibited typical toughness rupture. The resin system possessed the best mechanincal properties after post curing for 2 h at 200 ℃. Hydrothermal aging and ultraviolet radiation aging caused descend of mechanical properties. Retention ratios of both impact strength and flexural strength of the modified system exceeded 95 % when epoxy resin concentration was less than 30 %.更多还原