Preparation and properties of biodegradable antibacterial polylactic acid/modified chitin antibacterial agent composites

As a biodegradable material, polylactic acid (PLA) is widely used in healthcare industries, however, its bacterial properties cannot meet the requirements. Chitin, a natural antibacterial agent, is difficult to directly melt blend with PLA due to agglomeration. In order to enhance the compatibility between chitin and PLA, in this study, firstly, chitin was decomposed by cellulase to prepare enzymolysis chitin (EC). The viscosity and particle size of EC were measured and the optimal enzymolysis conditions were chosen. Then, the modified chitin antibacterial agent (MCAA) was prepared by mixing EC with glyceryl triacetate (GTA) and polyethyleneglycol (PEG), and the biodegradable PLA/MCAA composite was prepared by melt blending. Finally, the tensile, thermal, antibacterial properties, and the micromorphology of the PLA/MCAA composite were investigated. The results show that at a pH of 6.4 and a temperature of 55 degrees C, EC exhibited low viscosity and particle size after an enzymatic hydrolysis time of 4.5 h. Compared with PLA, PLA/MCAA composite exhibited better antibacterial effects against Escherichia coli and Staphylococcus aureus. Furthermore, in comparison to the PLA/chitin composite, there was less agglomeration in the PLA/MCAA composite, and the particle distribution of MCAA was more uniform.