聚醚扩链脲增韧环氧树脂体系的冲击性能及其断裂面形态结构

聚醚扩链脲增韧环氧树脂体系的冲击性能及其断裂面形态结构

Morphological and Impact Behavior of Epoxy Resin Toughened by Chain-extended Urea Containing Polyether

The fracture surface morphology of epoxy resin E 51/dicyandiamide(E 51/dicy) curing system toughened by chain extended urea containing polyether has been investigated by SEM as function of the morphology, dynamic mechanical behavior and impact strength. The fracture surface of the modified systems was found to display tough fracture feature, markedly different from that of the unmodified system. A lot of microcave, i.e. microphase of rubber , could be observed in homogeneous distribution on the fractured surface of the modified systems . Presence of two phase microstructure of the modified cured systems leads to the significant increase in impact strength. The impact strength of the modified system was affected by the amounts of chain extended urea and the molecular mass of the PPG flexible spacer in the chain extended urea, when the amounts of chain extended urea was 14%(mass fraction), the highest impact strength of E 51 /dicy/U 1(extended chain urea containing PPG flexible spacer with molecular mass 1 000 ) system was achieved which was 8 times that of the unmodified E 51/dicy curing system.