Fabrication of super-tough ternary blends by melt compounding of poly(lactic acid) with poly(butylene succinate) and ethylene-methyl acrylate-glycidyl methacrylate

Abstract

Herein, we describe the fabrication of novel super-tough ternary blends by simple melt compounding of poly(lactic acid) (PLA) with poly(butylene succinate) (PBS) and ethylene-methyl acrylate-glycidyl methacrylate (EGMA). The occurrence of reactions between the above three constituents was evidenced by mixing torque and Fourier transform infrared spectroscopy analyses and resulted in improved interfacial adhesion. Moreover, surface energy analysis indicated that EGMA was selectively localized at the PLA-PBS interface, and the cryofracture morphologies of as-prepared samples indicated that the inclusion of EGMA improved the compatibility between PLA and PBS phases. Compared to virgin PLA, the ternary blend containing 10 wt% PBS and 12 wt% EGMA exhibited a 32 times higher impact strength (98 kJ/m2), an only 44% loss of tensile strength (38 MPa), and superior stretchability (elongation at break = 460%). The observed property improvements were ascribed to in situ reactions between PLA, PBS, and EGMA and to the formation of elastic graft copolymers at phase boundaries. Ultimately, comparison of as-prepared samples with previously reported blends demonstrated that the former exhibited superior toughness and comparable stiffness, revealing that our work opens new avenues to expand the applications of PLA-based biodegradable products.