Synergistic toughening and reinforcement of poly(lactic acid) with epoxy‐terminated hyperbranched polymers

Abstract

Poly(lactic acid) (PLA) is an eco‐friendly and biodegradable material. However, its molecular chain was rigid and showed limited toughness. In this work, PLA was modified with epoxy‐terminated hyperbranched polymer (EHBP) by melt blending to improve the toughness. The results showed that epoxy groups within EHBP reacted with carboxyl and hydroxyl groups of PLA, forming chemical micro‐crosslinking. In addition, intermolecular hydrogen bonds were also formed between EHBP and PLA. The combined action of the above two aspects ultimately improved the toughness and strength of PLA. The mechanical property tests results showed that the mechanical properties of PLA improved best when 2.5 phr of EHBP was added. At this point, compared with neat PLA, the maximum tensile strength, impact strength, elongation at break, and flexural modulus of PLA/EHBP increased by 17.4%, 54.5%, 107.1%, and 25.8%, respectively, compared to those of neat PLA. It achieves the goal of simultaneously enhancing the toughness and strength of PLA and subsequently expands its potential application applications.