Studies on the properties of a thermosetting epoxy modified with chain-extended ureas containing hydroxyl-terminated polybutadiene

A series of chain-extended ureas (U-TPBn) containing hydroxyl-terminated polybutadiene spacer were synthesized and used to modify epoxy resin based on a diglycidyl ether of bisphenol A and dicyanodiamide. The ultimate aim of the study was to enhance the curing reactivity and improve the toughness characteristics of the brittle epoxy matrix. The curing behavior, viscoelastic properties, impact response and fracture surface morphology of the curing systems were systematically investigated. DSC analysis reveals that the curing reactions of the epoxy systems are greatly accelerated with the addition of U-TPBn. Impact tests show that the modifiers are very effective in toughening the epoxy resin.