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

The hydrolytic and Pseudomonas lipase catalysed enzymatic degradation was studied for PDC multiblock copolymers consisting of poly(epsilon-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 degradation behaviour is determined by the PPDO segments. Degradation time intervals up to 200h 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.