生态包装薄膜内多级有序纳米片层结构的原位定制及其阻隔机理

生物可降解薄膜是一类新型生态包装材料，但气体阻隔性能差等问题却制约了它在高阻隔包装领域的应用。巧妙设计薄膜中非渗透组分的分散状态能够增加气体分子的迂回路径而大幅度提高其基体的阻隔性能。鉴于此，本研究拟以生物可降解聚乳酸/聚乙醇酸（PGA）合金为例，通过合金内海岛结构的界面增容与双轴形变，原位构筑含有巨量非连续PGA取向纳米片的高阻隔单层复合薄膜，建立大面积制备聚合物二维纳米空间的新策略，以及受限空间内双轴拉伸诱导PGA冷结晶的新模型；深入研究分子取向、界面附生、空间效应和加工条件等因子诱导PGA取向结晶的新机制与控制方法；通过构建结构与性能的关系，从分子和纳米尺度揭示多级有序片层结构与基体取向结晶协同阻隔分子渗透的机理；最后进行中试试验并建立规模化制备可降解与可再生的高阻隔生态包装薄膜的普适性新技术。这不仅可以丰富聚合物受限结晶的理论体系，还有望推动高阻隔包装行业的技术革新与进步。

Biodegradable film is a new type of ecological packaging material, but the poor gas barrier properties have limited its application in the field of high-barrier packaging. Smart design of the dispersion state of non-permeable components in the film can increase the tortuous path of gas molecules and then greatly improve the barrier performance. In view of this and taking biodegradable poly (lactic acid)/poly (glycolic acid) (PGA) alloys as an example, this study intends to in situ construct single-layer high-barrier films with numerous discontinuous and oriented PGA nanosheets inside via interfacial compatibilization and biaxial deformation of the sea-island structures. A new strategy for preparation of two-dimensional polymeric nanospace and a new model for a 2D-stretching induced PGA cold crystallization in the confined space will be established. The mechanism and control methodology for the PGA oriented crystallization that influenced by factors such as molecular orientation, interfacial epitaxy, space confinement and processing conditions will be deeply investigated. As a consequence, the synergetic barrier mechanism of the multi-ordered lamellar structure and the matrix crystallization will be revealed on molecular and nano- levels based on the structure-property relationships. Finally, the experiments will be scaled up, and universal technologies for the large-scale preparation of degradable and renewable high-barrier films could be developed. Therefore, this project will not only enrich the theory of confined polymer crystallization, but also promote the technique innovation and improvement in the high-barrier packaging industry.