Mechanical properties and lipase-catalyzed biodegradation of alpha-methyl, epsilon-caprolactone/epsilon-caprolactone copolymers obtained by chemical modification of poly(epsilon-caprolactone)

Abstract

Novel (e-caprolactone)-based copolymers of different compositions were synthesized by allowing methyl iodide to react with the polycarbanion that resulted from the action of lithium diisopropylamide on poly(e-caprolactone) in THF at −70°C under argon atmosphere. The copolymers were characterized by various techniques, namely 1H nuclear magnetic resonance, size exclusion chromatography, differential scanning calorimetry, x-ray diffraction and viscoelasticimetry. They were submitted to hydrolytic and lipase-catalyzed enzymatic degradation in comparison with genuine PCL. The Young modulus depended on the degree of methylation. In contrast, loss angle and glass transition temperature did not depend on this parameter. It is shown that the lipase-catalyzed degradation of methylated PCL is much slower than in the case of genuine PCL.