Synthesis of novel pseudo amino acid/functional ε-caprolactone polyesters and photo-cross-linked networks

Novel copolymers of trans-4-hydroxy-L-proline (Hpr) and epsilon-caprolactones bearing protected functional groups (4-henzyloxy and 4-acryloyloxy) were synthesized via direct melt copolymerization with 1.5 wt% stannous octoate as catalyst at 140degreesC for 24 h. The synthesized copolymers were characterized by IR spectroscopy, proton nuclear magnetic resonance, differential scanning calormietry and viscometry using Ubbelohde type viscometer. The glass transition temperature (T-g) of the copolymers shifted to lower with increasing molar ratio of epsilon-caprolactone derivatives. The poly(N-benzyloxycarbonyl-Hpr-co-4-acryloyloxy-epsilon-caprolactone) bearing a pendant acrylate groups can be cross-linked by ultraviolet light irradiation in the presence of benzyl diethyl ketal, giving a new biodegradable network.