Role of stereocomplex in advancing mass transport and thermomechanical properties of polylactide

Designing high-performance renewable polylactide (PLA) based materials will assist in achieving the full potential of PLA as a sustainable alternative to fossil-based polymers, addressing the current challenge of low circulation of PLA in the green bioeconomy due to low market share. By simply mixing lactide enantiomers, the stereocomplex (SC) provides a unique opportunity to build a green material platform without the need for harmful chemicals. The SC crystal and physical crosslinking structure empower stereocomplex PLA (SC-PLA) with advanced mass transport and thermomechanical properties, such as higher gas/vapor barrier and heat deflection temperature than those of homochiral (HC) PLA (HC-PLA). And the emerging practices to embed SC in lactide-based copolymers indicate growing potential to widen the applications of novel synthetic polymers from renewable resources benefiting from the unique SC structure. Therefore, understanding the structure-property relationship of SC-PLA based materials is urgently needed to implement the benefits of SC in material design and application development. This review exclusively summarizes the recent improvements of the mass transport and thermomechanical properties achieved in various SC-PLA systems, emphasizing the structure-property relationships and discussing the current challenges and possible future directions.