Selective enzymatic degradation of poly (Epsilon-caprolactone) containing multiblock copolymers

Abstract

The hydrolytic and Pseudomonas lipase catalysed enzymatic degradation was studied for PDC multiblock copolymers consisting of poly(e-caprolactone) (PCL) segments and poly(p-dioxanone) (PPDO) segments with variable composition. The enzymatic degradation of these multiblock copolymers is significantly accelerated by Pseudomonas lipase in contrast to the hydrolytic degradation where the deg-radation behaviour is determined by the PPDO segments. Degradation time intervals up to 200 h are selected, where the PPDO segments remain stable and do not contribute to the degradation process. A linear correlation between weight loss and increasing PCL content of the multiblock copolymers was found. X-ray diffraction data confirm that both crystalline and amorphous PCL are attacked by the enzymes. SEM cross-section images reveal that Pseudomonas lipase penetrates into the PDC polymers. The present study impressively demonstrates that selective enzymatic degradation of PCL containing multifunctional polymers is a beneficial tool for controlling their degradation properties.