Sustainable Composites from Biodegradable Poly (lactic acid) Modified with Epoxy-Terminated Poly (propylene glycol) Ether: Preparation and Performance

The inherent brittleness and low crystallization rate of polylactic acid (PLA) limit its applications. While conventional methods can enhance the toughness of polyacrylonitrile to some extent, balancing its transparency, mechanical properties, and processability remains a significant challenge. Therefore, this study employed poly (lactic acid)/polypropylene glycol diglycidyl ether (PPGDGE) as a modifier to prepare a blend that simultaneously enhances crystallinity, mechanical properties, and processability while maintaining transparency. Results indicate that at a PPGDGE content of 25 phr, the PLA/PPGDGE composite exhibits approximately 70% and 60% decreased in tensile strength and glass transition temperature (T _g ), respectively, compared to pure PLA. Notched impact strength and elongation at break improve by approximately 40-fold and 65-fold, respectively, relative to pure PLA. Crystallinity exceeded that of pure PLA by over 5-fold, confirming the ability of PPGDGDE to promote ordered arrangement of PLA molecular chains. As PPGDGE content increased, the melt flow rate and equilibrium torque of composite continued to improve. Concurrently, PPGDGE exhibited transparency comparable to PLA, indicating structural compatibility between the two materials that preserves composite transparency. This study establishes both theoretical and practical foundations for expanding the application domains of PLA.