Lipase-Catalyzed Transesterification of Polyesters to Ester Copolymers

Lipase-catalyzed intermolecular transesterification between two different polyesters has been carried out using in toluene. The transesterification of poly(ε-caprolactone) (PCL) and (1,4-butylene adipate) took place via catalysis of lipase from Candida antarctica to give an ester copolymer. 13C NMR analysis showed that the resulting polymer was not a mixture of the starting polyesters, but a copolymer consisting of both units. The reaction temperature and solvent amount greatly affected the microstructure of the ester copolymer. Under appropriate conditions, the random copolymer was formed. The enzymatic transesterification has been monitored by size exclusion chromatography (SEC) and 13C NMR. Ester copolymers were enzymatically obtained from PCL and other poly(α,ω-alkylene dicarboxylate)s and their microstructure depended on the polyester structure.