Biobased, biocompatible, and biodegradable poly­(lactic acid), PLA, possesses unique properties that give it high potential for a wide range of applications. However, its low thermal stability and brittleness are major obstacles for its use. In this study, both the thermal stability and toughness of PLA were simultaneously improved via stereocomplexation and reactive blending, by generating alloys composed of two PLA enantiomers, PLLA and PDLA, together with poly­(ethylene-ran-methylacrylate–ran-glycidyl methacrylate), EMA-GMA. It was found that reactive blending at 200 °C was very effective in generating alloys with high degrees of stereocomplex (sc) crystallinity and that the interfacial reaction between PLA and EMA-GMA contributed to a significant improvement in toughness. Most importantly, a (40/40/20)­PLLA/PDLA/EMA-GMA film with high sc crystallinity exhibited both much higher tensile impact strength and thermal stability than neat PLLA, retaining high storage modulus up to 210 °C. The scPLA alloys also exhibited superior chemical resistance to neat PLA. Thus, it was demonstrated that simultaneous complexation and the interfacial reaction transform PLA to the level of high performance materials.

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