Abstract
Poly(e-caprolactone) was blended with various polylactide-based polymers and processed to films by the solution casting method. 25/75, 50/50, 75/25, 90/10 and 95/5 (w/w) poly(e-caprolactone)/poly(L-lactide) blends, and 95/5 (w/w) blends of poly(e-caprolactone) with a poly(D-lactide), a 50/50 (w/w) poly(L-lactide)-poly(D-lactide) mixture, and a poly(L-lactide-co-e-caprolactone) copolymer were considered comparatively. The various phase-separated films were allowed to degrade in the presence of Pseudomonas lipase, biodegradation being monitored by proton nuclear magnetic resonance, size exclusion chromatography, differential scanning calorimetry, X-ray diffraction, and environmental scanning electron microscopy. The formation of separated phases during solvent evaporation and their morphologies are discussed. The introduction of poly(L-lactide) dramatically decreased the degradation rate of poly(e-caprolactone)/poly(L-lactide) blends. The higher the percentage of poly(L-lactide), the slower the degradation, the presence of cracks and increasing the lipase concentration acting in favor of the enzymatic degradation. Long-term enzymatic degradation of the various 95/5 blends was investigated over 480 hours. The poly(e-caprolactone) phase was enzymatically degraded by the lipase regardless of the blend type, the degradation rate depending on the nature of the co-components.