Biodegradable vinyl functional branched copolymers were successfully synthesized by the oxyanionic copolymerization of -caprolactone (-CL) and glycidyl methacrylate (GMA).Potassium hydride (KH) and benzyl alcohol (BA) were employed as the initiators.The structures and properties of the resulted copolymers were studied in detail by Flourier transform infrared spectroscopy (FTIR)

size exclusion chromatography (SEC)

nuclear magnetic resonance spectroscopy (NMR)

differential scanning calorimetry (DSC)

thermogravimetric analysis (TGA) and scanning electron microscopy (SEC).The results showed that oxyanions displayed high activity for the copolymerization of -CL and GMA

resulting degradable copolymers with pendant vinyl groups in one step.Increasing the GMA/-CL feed ratio

the weight-average molecular weight of the copolymers increased from 6.70103 to 1.19105

the degree of branching increased from 0.06 to 0.14

but the degree of crystallinity decreased from 47.6% to 0.The NMR results suggested that the copolymer retained up to 67% pendant vinyl groups

which could further be tailored via the thiol-ene click reaction.Due to the large amount of hydroxyl groups

the resulted copolymers could react with toluene-2

4-diisocyanate

forming a degradable polyurethane film.The SEC result showed that the surface of the polyurethane film became very rough after immersing in a lipase buffer solution for 15 days.