Study on toughening polylactic acid/poly(butylene adipate-co-terephthalate) with a curing network based on dynamically crosslinked epoxidized soybean oil.

A dynamically crosslinked network VEC (vulcanized ESO and CA) was synthesized in situ via zinc acetate-catalyzed epoxy ring-opening between epoxidized soybean oil (ESO) and anhydrous citric acid (CA), then incorporated into polylactic acid (PLA)/polybutylene adipate terephthalate (PBAT) blends to enhance interfacial compatibility. The dynamic ester-exchange network acted as an intermediate phase, improving the integration of the flexible PBAT phase within the rigid PLA matrix. VEC content critically influenced mechanical properties, with in-situ crosslinking during dynamic vulcanization enhancing chain interactions and blend homogeneity. The optimized composite exhibited elongation at break and impact strength of 434.67 % and 9.12 kJ/m, corresponding to 1.61- and 2.02-fold increases over PLA/PBAT (70/30). The blends exhibit reprocessability, and after recycling and remolding, the elongation at break achieves 325.875 %, representing a 1.2-fold enhancement compared to PLA/PBAT (70/30). The incorporation of the dynamic crosslinked solidification network VEC significantly improves the melt strength of the PLA/PBAT blends, and the composites achieved complete degradation under alkaline conditions and enhanced hydrophobicity. SYNOPSIS: In this paper, epoxidized soybean oil curing network is introduced into PLA/PBAT to obtain biodegradable materials with excellent properties.