HE Shangjin, SHI Keyu, BAI Jie, DU Zongjie, ZHANG Baolong. STUDIES ON THE PROPERTIES OF E-51/DICYANDIAMIDE SYSTEM MODIFIED WITH IMIDAZOLE-TERMINATED CHAIN-EXTENDED UREA[J]. Acta Polymerica Sinica, 2001,(6):735-739.
HE Shangjin, SHI Keyu, BAI Jie, DU Zongjie, ZHANG Baolong. STUDIES ON THE PROPERTIES OF E-51/DICYANDIAMIDE SYSTEM MODIFIED WITH IMIDAZOLE-TERMINATED CHAIN-EXTENDED UREA[J]. Acta Polymerica Sinica, 2001,(6):735-739.DOI:
A chain-extended urea(TIEU) containing flexible spacer was synthesized from polypropylene glycol PPGl000
toluenediisocyanate (TDl) and imidazole.The reactive activity
dynamic mechanical behavior
impact property and morphology of the curing systems were systematically investigated by DSC
viscoelastic spectroscopy
impact tester and SEM
respectively.Results show that the curing activity of modified E-51/dicy system was so greatly enhanced that the apparent activation energy of curing reaction is reduced from 131 kJ/mol for the unmodified system to 75~80 kJ/mol.The curing reaction mechanism of E~51/dicy system accelerated by TIEU was a little different from that of the system accelerated by imidazole.The impact stength of the curing systems modified with TIEU was 2~3 times higher than that of the unmodified system
while the glass transition temperature and modulus were little changed.and the fracture surfaces of the modified systems displayed tough fracture feature.