Poly(lactic acid) or
poly(lactide) (PLA) is a renewable, bio-based, and biodegradable aliphatic thermoplastic
polyester that is considered a promising alternative to petrochemical-derived
polymers in a wide range of commodity and engineering applications. However, PLA is inherently brittle, with less than 10% elongation at break and a relatively poor impact strength, which limit its use in some specific areas. Therefore, enhancing the toughness of PLA has been widely explored in academic and industrial fields over the last two decades. This work aims to summarize and organize the current development in super tough PLA fabricated via
polymer blending. The miscibility and compatibility of PLA-based blends, and the methods and approaches for compatibilized PLA blends are briefly discussed. Recent advances in PLA modified with various
polymers for improving the toughness of PLA are also summarized and elucidated systematically in this review. Various
polymers used in toughening PLA are discussed and organized:
elastomers, such as
petroleum-based traditional
polyurethanes (
PUs), bio-based
elastomers, and biodegradable
polyester elastomers; glycidyl
ester compatibilizers and their copolymers/
elastomers, such as
poly(ethylene-co-glycidyl methacrylate) (EGMA), poly(
ethylene-n-
butylene-
acrylate-co-
glycidyl methacrylate) (EBA-GMA); rubber;
petroleum-based traditional plastics, such as PE and PP; and various biodegradable
polymers, such as
poly(butylene adipate-co-
terephthalate) (PBAT),
polycaprolactone (PCL),
poly(butylene succinate) (PBS), and natural macromolecules, especially
starch. The high tensile toughness and high impact strength of PLA-based blends are briefly outlined, while the super tough PLA-based blends with impact strength exceeding 50 kJ m-2 are elucidated in detail. The toughening strategies and approaches of PLA based super tough blends are summarized and analyzed. The relationship of the properties of PLA-based blends and their morphological parameters, including particle size, interparticle distance, and phase morphologies, are presented.