Modification of polylactic acid fabric by two lipolytic enzyme hydrolysis

Polylactic acid (PLA) has received considerable attention as a biomass material in the textile industry. To use PLA fiber in the textile industry, suitable post-processing is needed. To establish enzymatic finishing of PLA fibers, we evaluated the hydrolytic activities of two representative lipolytic enzymes; lipase and esterase. In addition, we established the optimal hydrolytic treatment conditions of each enzyme. Results showed that the optimal lipase and esterase treatment conditions are a pH of 8.0, a temperature of 40 degrees C, a concentration of 10% owf, and a calcium chloride concentration of 10 mM. PLA fabrics experienced a weight loss of about 0.7% from enzyme treatment with no loss of tensile strength. Biodeterioration due to enzymatic hydrolysis were observed in scanning electron microscopy images. There was an approximately twofold improvement in moisture regain by enzymatic hydrolysis. Finally, X-ray diffractometry identified a new peak localized at 2 theta = 18.5 degrees after enzyme treatment. The degree of crystallinity was increased and the crystallite size was decreased.