聚醚扩链脲增韧环氧树脂/双氰双胺固化体系

THE STUDY OF THE EPOXY RESIN/DICYANDIAMIDE CURING SYSTEM MODIFIED BY CHAIN-EXTENDED UREA CONTAINING POLYPROPYLENE OXIDE

以聚醚PPG1000、异氰酸酯、二胺为原料,合成了聚醚扩链脲(EU),系统考察了EU改性的环氧树脂E-51/双氰双胺(dicy)固化体系的固化反应活性、动态力学行为、冲击性能和断裂面形态结构。并对体系的冲击性能、形态结构与动态力学行为之间的关系进行了探讨。结果表明,改性体系固化反应活性明显提高,固化反应表观活化能降低,固化反应峰顶温度从190℃降低至140℃,固化反应的表观活化能由145.5kJ/mol降至73.6kJ/mol;改性体系冲击强度明显提高,较未改性的E-51/dicy体系提高了9倍,较小分子取代脲改性的E-51/dicy体系提高了7倍;其冲击试样断裂面的形态具有明显的韧性断裂特征。

A novel chainextended ureas (EU) containing 1000 (PPG1000) spacers was synthesized. The reactive activity , dynamic mechanical behavior , impact property and morphology of the EU modified E51/dicycuring system were systematically investigated, the relationships among the dynamic mechanical behavior, impact strength and morphology were also discussed. Results show that the curing activity of EU modified E51/dicy curing system is so greatly enhanced that the curing reaction peak temperature decreases from 190 ℃ to 140 ℃, and the apparent activation energy of curing reaction is reduced from 145.51 kJ/mol to 73.61 kJ/mol. The impact strengh of the EU modified curing system is increased significantly, it is 8 times higher than that of the unmodified E51/dicy curing system, 3 times higher than that of the E51/dicy curing system modified by substituted urea without PPG spacer, the fracture surfaces of the E51/dicy/EU system displayes tough fracture feature.