Optimization of Comprehensive Performance of Polylactic Acid by Chitosan Blend Modification

Polylactic acid (PLA), a biodegradable polymer, exhibits superior mechanical strength and processability. However, its broader adoption is hindered by inherent brittleness, low hydrophilicity, and sluggish crystallization kinetics. Chitosan (CS), a natural polysaccharide renowned for its biocompatibility and biodegradability, offers potential to address these limitations. While both materials have garnered significant attention in materials science, research on their integration via melt blending and the resulting performance enhancements for food-contact plastics remains understudied. This research comprehensively explores how different levels of CS content, from 0% to 10%, impact the characteristics of chitosan/polylactic acid (CS/PLA) composites. It specifically analyzes the influence of various CS concentrations on the mechanical attributes, crystallization behavior, thermomechanical properties, and rheological performance of these composites. The study concludes that a CS content of 4% in the CS/PLA composite results in the best overall properties. At this point, its elongation at break and impact strength reached their maximum values (16.16% and 20.63 kJ/m²), representing increases of 23.9% and 15.7% compared to pure PLA. At this particular concentration, CS is evenly distributed throughout the PLA matrix, acting as a heterogeneous nucleating agent. It facilitates the crystallization of the composite material and offers effective reinforcement. This study presents a promising approach for developing environmentally friendly and sustainable alternatives to fossil-based plastics, highlighting significant research value and practical application potential.