Synthesis and characterization of functionalized poly(ɛ-caprolactone)

Polyesters constitute an important class of materials for in vivo biomedical applications. Poly(ɛ-caprolactone) (PCL) is a hydrophobic biodegradable polyester which is employed to a lesser extent in drug delivery applications due to its rather limited range of physicochemical characteristics. Here, we present a new paradigm for the synthesis of functionalized PCL via copolymerization of caprolactone with α,ω-epoxy esters. Ethyl 2-methyl-4-pentenoate oxide was used as a monomer which was copolymerized with ɛ-caprolactone to yield random copolymers of poly(ɛ-caprolactone-co-ethyl-2-methyl-4-pentenoate oxide). The reaction conditions were optimized to generate functionalization greater than 25%. The use of ester-epoxides favors a statistical and uniform distribution of monomer along the polymer backbone, which while preserving some of the key properties of PCL such as glass transition that is below room temperature, allows the tailoring of the melting behavior of PCL. The strategy presented herein opens up new avenues for engineering PCL properties for biomedical applications.