聚乳酸（PLA）现有成核剂尺寸大、成核效率低，严重制约了其结晶速率、物理性能和应用领域。鉴于此，本研究拟从分子水平设计合成系列主链含有乙二酰胺链段的PLA杂化大分子，通过分子设计和氢键链段定向组装构筑纳米晶核，提出大分子自身异相成核的新思想。系统研究杂化大分子中氢键基团的数目、位置、链段结构和PLA链段长度等对晶核构筑的速度、尺度以及晶格参数的影响规律，建立杂化大分子诱导纳米晶核构筑的方法、理论及最佳杂化结构，结合实验数据与动力学模型阐明纳米晶核可控构筑的机理；深入研究纳米晶核与界面共价键协同诱导PLA分子链堆砌生长的新规律，剖析界面共价键对PLA分子链结晶行为的特殊作用机制；最后，通过成核与晶体结构调控制备透明、耐热且气体阻隔性能优异的可降解膜材料。本研究不仅将丰富传统成核与结晶理论，还将为超细晶核的可控构筑提供普适性技术路线、为高性能生物可降解材料的制备与性能调控提供重要的理论支撑。

Crystallization rate, physical properties and application range of poly (lactic acid) (PLA) are seriously restricted due to the large size and low efficiency of its nuclei. To solve these issues, PLA-based hybrid macromolecules with oxalamide segments in main chain are going to be designed and synthesized, and nano-sized nucleator is expected by molecular structure design and H-bonds assembly of oxalamide segments, then a novel idea on self-nucleation of macromolecules is raised. The effect of the amount, position and segmental structure of the H-bond units and the length of the PLA segments on the construction rate, size and lattice parameter of the nuclei will be systematically investigated. As a consequence, the method, theory and optimal hybrid structure for construction of the intramolecular nano-nucleator will be set up, and the corresponding construction mechanism will be illuminated based on the experimental data and dynamic model. The new packaging phenomena of the PLA chains induced by the nano-crystal nucleus and interfacial covalent bonds will be studied, and the synergetic effect of the interfacial covalent bonds on the crystallization behavior of the PLA chains will be analyzed as well. Finally, taking film as an example, biodegradable materials with transparency, heat-resistance and gas barrier properties will be made via crystallization and microstructure control. This work will not only enrich the traditional nucleation and crystallization theory, but also provide platform approach to super-thin crystal nuclei. Moreover, it would provide theoretical support for the preparation and property control of high-quality biodegradable materials.