Abstract: A copolymer (PBSe-PEG) was obtained from the polycondensation product of sebacic acid, PEG-200, and polyethylene glycol. The structure of PBSePEG was characterized by 1H-NMR; molecular weight and its distribution were tested by GPC; crystallinity and thermal properties of the copolymers were analyzed by WXRD, DSC and TGA, and the degradation property was tested by lipase N435. GPC gave a molecular weight about 5×104; 1H-NMR proved that PBSe-PEG had a similar crystal structure to neat PBSe. With increasing content of PEG-200, both Tm and Tc of the copolymer decreased. Compared with PBS，lipase N435 catalyzed degradation of PBSe-PEG better.

Key words: poly(ethylene glycol), poly(butylene sebacate), block copolymer, long chain dibasic acid, enzymatic degradation