左旋聚乳酸（PLLA）与右旋聚乳酸（PDLA）的立构复合（SC）为环境友好型聚乳酸（PLA）材料的高性能化提供了一条重要途径。然而，尽管熔融加工是半结晶高分子材料最为常用的加工手段，但由于SC晶体的熔体结晶记忆效应很弱且在高于其熔点的熔融加工过程中极易引发分子链强烈的降解，因而采用熔融加工难以制得高性能的立构复合型聚乳酸（SC-PLA）制品。本项目受到粉末冶金的启发，提出一种采用低温（低于SC晶体熔点）烧结成型来制备高性能SC-PLA制品的新方法。拟从具有不同物性的SC-PLA粉末的制备出发，揭示物性对粉末颗粒的界面润湿以及界面处自由分子链通过相互扩散、配对、共结晶形成新SC晶体的影响，建立有效调控SC新晶体的含量与结构的基本方法，深入研究这些SC晶体对制品性能影响的科学规律，并探索采用低温烧结成型法开发多功能SC-PLA制品的可能性，最终为高性能多功能SC-PLA产品的开发提供理论基础。

Stereocomplexation between poly(L-lactide) (PLLA) and poly(D-lactide) (PDLA) provides an avenue to significantly enhance performance of eco-friendly polylactide (PLA). Unfortunately, although the manufacturing of semicrystalline polymers generally involves melt processing, it is still a huge challenge to fabricate stereocomplexed polylactide (SC-PLA) products from melt-processed PLLA/PDLA blends due to the weak crystallization memory effect of stereocomplex (SC) crystallites after complete melting as well as the substantial degradation of PLA chains at elevated melt-processing temperatures far exceeding their melting temperatures. Inspired by the concept of powder metallurgy, in this project, we propose a new method to fabricate high-performance SC-PLA products through low-temperature (lower than the melting temperatures of SC crystallites) sintering of powdery SC-PLA. The enantiomeric PLLA/PLLA chain segments from adjacent powder particles can interdiffuse across particle interfaces and co-crystallize into new sc crystallites capable of tightly welding the interfaces during the sintering process. After preparing the SC-PLA powders with different physical characters, we will reveal the influence of the physical characters on the interfacial wetting behavior of adjacent powder particles as well as the formation of the new SC crystallites. The basic approaches to tailoring SC crystallite structure will be established and the role of these SC crystallites in determining the product properties will be deeply investigated. Also, the possibility to develop multi-functional SC-PLA products using the low-temperature sintering method will be explored. The theoretical understandings obtained from this project are expected to provide a guideline for developing high-performance and multi-functional SC-PLA products.