含柔性间隔基的扩链脲增韧环氧树脂性能研究——环氧树脂／扩链脲／双氰双胺体系性能研究

合成了含不同分子量柔性间隔基的扩链脲（Ｕｉ），并对其与双氰双胺共同固化环氧树脂体系的反应活性、抗冲击性能、动态力学性能、形态结构及贮存性能进行了考察。结果表明：含分子量为４００的聚乙二醇柔性链的扩链脲／双氰双胺／环氧树脂固化体系的抗冲击强度较单纯双氰双胺／环氧树脂固化体系提高了７倍左右，其冲击试样断面电镜照片呈韧性断裂的特征。扩链脲的反应活性基本不受分子中聚乙二醇链段分子量的影响。环氧树脂／扩链脲／双氰双胺体系在５０℃下贮存期可达１～２天。

THE STUDY ON THE PROPERTIES OF EPOXY RESIN TOUGHED BY CHAIN-EXTENDED UREAS CONTAINING FLEXIBLE SPACERS THE STUDY ON THE PROPERTIES OF THE EPOXY RESIN/CHAIN- EXTEND EDUREAS/DICYANDIAMIDE SYSTEM

A series of chain-extended ureas containing polyethylene glycol (PEG) spacers with different molecular weight were synthesized and the reactive activity,impact strength,the dynamic mechanical behavior,the morphology and the storage property of the epoxy resin/Ui/dicyandiamide system were studied.Experimental results revealed that the impact strength of the epoxy resin/chain-extended urea containing PEG flexible spacer with molecular weight 400/dicyandiamide system was seven times higher than that of the epoxy resin/dicyandiamide system,and the SEM micrographs of the impact fractured surfaces howed the tough fracture characters. Results also showed that the molecular weight of PEG flexible spacers in chain-extended ureas basically had no influence on the reactive activity of the ureas.The storage life of epoxy resin/Ui/dicyandiamide systems at50℃ was one to two days.