生物质聚羟基脂肪酸酯纤维及其扭转拉伸诱导结晶研究

聚羟基脂肪酸酯(PHAs)是一类由微生物合成的可降解高分子材料，具有绿色、环保、可再生的优点，但同时存在加工耐热性差、熔体强度低、结晶速率慢和纤维脆性大的问题。本项目拟从化学结构设计和扭转拉伸外场诱导两方面调控PHAs的化学结构、熔体强度和结晶动力学。重点研究化学结构对PHAs耐热性、线性黏弹性、结晶结构和结晶动力学的影响，揭示扭转拉伸位置和拉伸工艺对纤维结晶取向的诱导关系，跟踪并研究生物质纤维的服役行为及其结构演变规律。项目最终制备一种集高热稳定性、高成核温度、快结晶速率等性能为一体的生物基新材料，探索发明一种扭转拉伸诱导生物基纤维结晶的新方法，阐明扭转拉伸实现 “分子链微束加捻”的机理。本项目的开展，不仅为开发生物质PHAs纤维提供新的方法、为构建高强度生物基纤维打开新的思路，还能促进高分子化学、凝聚态物理学、工程学等学科的交叉发展，扩宽生物质聚酯的应用范围。

Polyhydroxyalkanoates (PHAs) is a kind of green, environmental-friendly ,biodegradable and renewable polymeric materials synthesized by microorganisms. However, their developing prospects are limited by poor heat resistance in processing, weak melt strength, slow crystallization rate and the low fiber toughness. In this project, the chemical structures, melt strength and crystallization kinetics of PHAs are regulated through molecular chain structure design and the induction of twist-draw process. And the focus of this project are studying the effects of PHAs’ chemical structure on heat-resistance, linear viscoelasticity, crystalline structure and crystallization kinetics, which reveals the inducing relationships of reverse stretching position and stretching technique on oriented crystallization process of fibers, and tracks the evolution laws of service behavior and fiber structure. Also, in this project, better thermal stability, high nucleate temperature and fast crystallization rate bio-based fibers were fabricated, and mechanism of realizing molecular chain microbeam twisting by reverse-stretch was clarified. In conclusion, this project, not only offers a new way to developbiomass PHAs fiber, a new idea of building high-strength bio-based fibers, but also promotes the development about intersection of polymer chemistry, condensed matter physics and engineering disciplines, which broadens the application field of bio-based polyester fibers.