Synthesis, properties and in vitro degradation of carboxyl-bearing PCL

Aliphatic polyesters derived from lactic and glycolic acids (PLAGA) are the most attractive degradable polymers with respect to biomedical and environmental applications.Poly(-epsilon -caprolactone), PCL, is a hydrophobic highly crystalline aliphatic polyester that is more resistant to hydrolytic degradation than PLA. It is not biodegradable in animal body but is rapidly degraded by outdoor microorganisms. In order to increase the rate of hydrolysis of the material, carboxyl-bearing PCL copolymers (PCLCOOH) were synthesized by anionic activation with LDA and reaction of CO2 on the polycarbanion. Variations in crystallinity, thermal properties and hydrophilicity caused by the presence of the pendent carboxyl groups were investigated. The degradation behavior of PCLCOOH was assessed by the evaluation of water uptake, mass loss, molecular masses and ESEM microphotographs. A dramatic increase in the hydrolytic degradation rate was observed compared with pure PCL, thus PCLCOOH can now be considered as a hydrolytically degradable polymer.