Interfacial modulation of PLA/PBAT blends by synergistic toughening of reactive chain extenders with epoxidized natural rubber

Abstract

With growing public attention to environmental issues and sustainable development, biodegradable bio-based plastics have attracted widespread interest. This study reveals the chemical-physical synergistic regulation mechanism of biodegradable PLA/PBAT blends through the synergistic modification of epoxidized natural rubber (ENR) and epoxy chain extender (ADR). Interfacial interaction analysis shows that PBAT tends to encapsulate ENR to form aggregates. Prepared via a one-step melt blending method, ADR constructs a PLA/PBAT chemical crosslinking network through epoxy groups. Meanwhile, PBAT encapsulates ENR via hydrogen bonding, promoting the transformation of ENR elastomers from disordered physical aggregates to uniform dispersion, which are embedded in the crosslinking network as effective toughening units. The resulting PLA/PBAT/ENR/ADR (80:20:2:5) blends exhibit excellent mechanical properties: the elongation at break increases to 498 %, and the notch impact strength after annealing reaches 100.6 kJ/m², representing significant improvements of 2583 % and 4374 % compared to pure PLA, respectively. This blend combines excellent rheological properties, mechanical properties, and sustainability, providing a theoretical framework for "chemical crosslinking-physical morphology" synergistic regulation in the design of high-performance bio-based materials.

Keywords: Crystallization behavior; ENR; Epoxy group; PLA; Rheological properties; Synergistic toughening.