Abstract
Enzymatic hydrolysis of poly(L-lactic acid)(PLLA), poly(butylene succinate)(PBSU) and their blends was performed in the phosphate buffered solution of pH7.4 at 37°C. Cholesterol esterase was used as the enzyme. The blend films before and after hydrolysis were characterized. From the results of Wide Angle Xray Deffraction measurement for the quench films before hydrolysis, PLLA was amorphous and PBSU was crystallized. The spherulite of PLLA was observed in the blend films during annealing at 130°C. The degradation rate of the blend films decreased with increasing the mixing ratio of PLLA and with increasing the crystallinity of PLLA. From the results of FT-IR measurement, the dominant component at the surface of PLLA/PBSU=50/50 blend film before hydrolysis was PBSU, but after hydrolysis, the dominant component at the surface was PLLA. In this work, we found that the degradation rate of the blend films depends on not only the mixing ratio of PLLA but also the crystallinity of PLLA.
