可全生物降解的聚乳酸共混物薄膜中纳米带构筑与气体阻隔机理研究

Compared with traditional packaging materials, polymer films are widely applied packaging field due to their lightweight, transparency, inexpensive, and easily processing features. White pollution and oil crisis brought out by plastic film is increasingly serious, therefore, Therefore, the development of new theory and technology for preparing high barrier and biodegradable polymer film has been a central issue in packaging and plastic industry. In the current study, PBS were taken to toughen polylactic acid (PLA),then controlling processing parameters at the same time to generate PBS nanofiber in PLA matrix and eventually establish highly orientated and uniformly distributed PBS nanobelts and high density PBS crystals, in order to build more tortuous gas molecules permeation path and to prepare full biodegradable and high barrier nanocomposite films. Through systematic study the formation of in situ PBS nanofiber in PLA matrix, eluciate the influence of external processing field on content, orientation and distribution of PBS nanobelts and dense PBS crystals, establish PBS/PLA composite membrane system, establish the connection of processing field, microscopic structure of PBS nanobelts, and barrier performance of the composite film, further exploring the mechanism of improving the barrier property of composite film dramatically by taking advantage of PBS nanobelt structure.

与传统包装材料相比，聚合物薄膜以质轻、透明、价廉等特性，在包装材料领域有广泛应用，但其带来的白色污染、石油危机严重。因此，研究可生物降解聚合物薄膜阻隔新原理新技术，开发高阻阻隔可生物降解的薄膜材料成为“热点”。本项目将少量PBS与PLA熔体共混，共混物高粘流体通过窄缝口模挤出，再被热拉伸，并快速冷却，使PBS相在PLA基体中充分形变并形成沿拉伸方向高度取向的PBS纳米纤维，在PLA为半固态而PBS为熔融态时滚压成膜，同时PBS纳米纤维在滚压过程中形成高度取向的PBS纳米带，作为“纳米阻隔墙”来构建更加曲折的气体分子渗透路径，迫使气体分子寻找更长的路径扩散，显著提高薄膜气体阻隔性能。通过系统研究PBS纳纤的形成条件，探明加工外场对PBS纳米带及PBS晶体的含量、取向度及分布状态等的影响，建立加工外场、微观结构及阻隔性能之间的联系，深入阐述PBS纳米带精细结构提高薄膜气体阻隔性能的机理。

与传统包装材料相比，聚合物薄膜以质轻、透明、价廉等特性，在包装材料领域有广泛应用，但其带来的白色污染、石油危机严重。因此，研究可生物降解聚合物薄膜阻隔新原理新技术，开发高阻隔可生物降解的薄膜材料至关重要。本项目开展了复合膜的结构与性能关系研究。通过结构调控，改善了PLA复合薄膜的阻隔性、刚韧平衡性等性能。改善了其他聚合物复合薄膜的阻隔性、机械性能及透明性等性能。制备了用于热管理及高导热领域的聚合物复合薄膜。建立了加工外场、微观结构及宏观性能之间的联系，深入阐述了精细结构提高复合薄膜性能的机理。