Supertough polylactide-based materials with fast shrinking property by stereocomplex crystallites through in situ reactive blending

Abstract

Polylactide (PLA), one of the most innovative biopolymers with excellent performance, can be produced from plant-derived resources. However, the brittleness of PLA limits its further applications. In this work, supertough poly(L-lactide) (PLLA)-based materials with fast shrinking property have been prepared by blending PLLA, poly(D-lactide) (PDLA), and ethylene-acrylic ester-glycidyl methacrylate random terpolymer (EGMA). It was confirmed that PLLA and PDLA can react with EGMA to form a strong interfacial interaction. With the addition of PDLA component, the EGMA phase structure changed from a sea-island structure to a cocontinuous-like phase structure, and the stereocomplex (SC) crystallites appeared at the interface between PLLA matrix and EGMA phase. Compared to pristine PLLA, the ternary blend containing 70 wt% PLLA, 10 wt% PDLA, and 20 wt% EGMA exhibited high notched Izod impact strength (83.9 KJ/m2) and high elongation at break (242 %). XRD results indicate that only SC crystallites can be found in these PLLA/PDLA/EGMA blends. Interestingly, these supertough PLLA-based material films can shrink in hot water within 2 s without changing the mechanical property even after three stretching-shrinking cycles. The presence of SC crystallites and strong interfacial interaction between EGMA and PLLA matrix leads to significantly enhanced toughness, which opens a new path for high-performance PLLA-based materials in medical and packaging areas.