The use of aliphatic polyesters for biomedical applications is limited by the lack of functionality of their backbones. The aim of the following study was to develop a novel elastic scaffold material containing functional groups to be used for future derivatization to tether peptide ligands to support cell adhesion, migration, and differentiation. The elastomer was based on three-arm star copolymers composed of epsilon-caprolactone and a functionalized epsilon-caprolactone, 2-oxepane-1,5-dione, and end-terminated with acrylate groups. The elastomer thus contains a ketone and two approaches were examined for obtaining a photocrosslinkable elastomer containing functional groups: crosslinking followed by ketone reduction using sodium borohydride to generate pendant hydroxyl groups, and reaction of the ketone with hydrazines. Reduction of the ketone lead to degradation of the elastomer through transesterification and ethanolate mediated cleavage of the polymer backbone. Reaction with hydrazines did not degrade the polymer and resulted in efficient functionalization of the elastomer. (C) 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 8191-8199, 2008