Enhanced crystallization and plasticization of bio-friendly poly(lactic acid) films via synergistic effect of...

To address the threat posed by petroleum-based plastics to the global environment, poly(lactic acid) (PLA), known for its excellent mechanical strength and biocompatibility, is a promising alternative. Herein, we present a versatile strategy for preparing PLA-based materials with enhanced crystallization and toughness through one-step melt blending, aiming to solve the inherent brittleness and fragility issues of PLA films. The study delves into the synergistic effects of nucleating agent decanedioic acid, 1,10-bis(2-benzoylhydrazide) (NA300L), plasticizer polyethylene glycol (PEG), and chain extender epoxy-functionalized oligomer (ADR) on the crystallization, micromorphology, aging behavior, thermal degradation, and rheological behavior of PLA. Results show that compared to pure PLA, the crystallinity of the PLA₈₅/PEG₁₅/NA₁/ADR_0.5 compound rises from 0.2 % to 40.5 %, and the half-crystallization time (t_1/2) shortens from 29.3 to 38.2 min to ∼0.8 min, indicating it can achieve satisfactory performance without extra annealing in practical applications. Additionally, this compound exhibits reduced plasticizer migration, enhanced thermal stability, improved rheological behavior, and excellent biodegradability and biocompatibility. As expected, its blown film samples also display outstanding biaxial tensile strength and elongation at break, with a machine direction (MD) elongation at break of 342 % and tensile strength of 51.1 MPa, while the transverse direction (TD) properties reach 114 % and 27.0 MPa, respectively. Overall, this study demonstrates that the synergistic effects of NAs, plasticizers, and chain extenders can effectively regulate the structural properties and usability of PLA compound films. It provides a straightforward and practical approach for developing high-performance bio-based polymers and highlights promising prospects for their commercial applications.