Synthesis and characterization of biodegradable amphiphilic PEG-grafted poly(DTC-co-CL)

A novel biodegradable copolymer, poly(5,5-dibromomethyltrimethylene carbonate-co-ɛ-caprolactone) (poly(DBTC-co-CL)) with pendant bromine groups, was synthesized via ring-opening polymerization (ROP) of ɛ-caprolactone (CL) and 5,5-dibromomethyltrimethylene carbonate (DBTC) using stannous octoate (Sn(Oct)2) as catalyst. Then the pendant bromine groups were completely converted into azide form, which permitted “click” reaction with alkyne-terminated polyethylene (A-PEG) by Huisgen 1,3-dipolar cycloadditions preparing biodegradable amphiphilic poly(DTC-co-CL)-g-PEG graft copolymer. The graft copolymer was characterized by nuclear magnetic resonance (NMR) and size-exclusion chromatography (SEC).