Ultrahigh strength and toughness of polylactide added with EGMA elastomer of a small amount processed via pressure-induced flow above the glass transition temperature

Abstract

Elastomer toughening is widely recognized as a highly effective strategy for enhancing the mechanical performance of plastics. However, the improvement in toughness generally comes at the cost of a drastic sacrifice in tensile strength. In this work, ethylene–acrylic ester-glycidyl methacrylate random terpolymer (EGMA) of a small amount of 5 % in mass was applied as a toughening agent of polylactide (PLA), with the assistance of a pressure-induced flow processing at above the glass transition temperature. The obtained PLA blend showed simultaneously improved tensile strength and impact toughness. The tensile strength and Young’s modulus maintained at a relatively high level of 58 MPa and 2.1 GPa, respectively, and the notched Izod impact strength reached up to 54 kJ/m2, which was 27 times higher than that for neat PLA (1.9 kJ/m2). The increased toughness was primarily attributed to a synergistic effect of the reduced crystal sizes, reduction in phase domain sizes and enhanced interfacial interactions. This study provided a cost-effective and feasible approach to achieving strong and super-tough PLA materials, which held a significant potential for PLA widespread applications.