左旋聚乳酸（PLLA）与右旋聚乳酸（PDLA）的立构复合（SC）为聚乳酸（PLA）工程塑料的开发提供了可能。然而，由于立构复合聚乳酸（SC-PLA）的脆性大、熔融稳定性很差（在熔融过程中PLLA/PDLA分子链对极易分离，导致所得SC-PLA制品中难以形成高含量的SC晶体），无法满足应用需求。与弹性体共混是提高SC-PLA韧性的一种简单有效的方法，而基体结晶又是影响共混物性能的关键结构因素。基于此，本项目创新性地提出通过“一步”反应性熔融共混在共混物熔体中形成梳形接枝共聚物（少量PLLA/PDLA分子链接枝到部分弹性体分子链上）、进而大幅改善基体熔融稳定性的新方法，并在微纳尺度上实现对SC-PLA基体结晶形态与结构的有效调控，深入研究基体结晶对共混物性能影响的规律，最终建立通过反应共混和结晶调控来制备高性能SC-PLA/弹性体共混物的理论框架，为SC-PLA工程塑料的定构加工提供新思路。

Stereocomplexation between enantiomeric poly(L-lactide) (PLLA) and poly(D-lactide) (PDLA) provides a robust solution for developing eco-friendly polylactide (PLA) engineering plastic with superb physicochemical properties. However, the practical applications of stereocomplex-type PLA (SC-PLA) have been significantly hindered by its inherent brittleness and poor melt stability (PLLA/PDLA chains would be decoupled from their helical pairs after complete melting and thus it is challenging to fabricate SC-PLA products containing high-content SC crystallites). Blending with various elastomers is a facile but effective method to enhance the toughness of SC-PLA and the matrix crystallization plays a key role in determining the blend performance. In this project, we propose a new strategy to substantially improve the melt-stability of SC-PLA matrix through reactive melt blending, where some PLLA/PDLA chains could be grafted onto elastomer chains and thus forming comb-like grafting copolymers. After tailoring crystal morphology and structure of the SC-PLA matrix at micro- and nanoscale levels, the influence of the matrix crystallization on the blend performance will be investigated, and finally a theory framework for preparing high-performance SC-PLA/elastomer blends through reactive blending and crystallization manipulation will be set up. After completing this project, it is expected to develop a new route for direct structuring SC-PLA-based engineering plastics.