Zhao Jianguo, Yang Mengcheng, Wu Binhang, Li Hang, Li Yiguo
School of Materials Science and Chemical Engineering, Ningbo University, Ningbo 315211, China.
Polymers (Basel). 2025 May 28;17(11):1508. doi: 10.3390/polym17111508.
Post-processing plays a vital role in the determination of the final structures and properties of oriented materials. As a sustainable candidate of oil-based poly(ethylene terephthalate), biobased poly(ethylene 2,5-furandicarboxylate) (PEF) reflects great promise in green fiber, film, and packaging applications, but it undergoes poor stress-induced crystallization (SIC) under tensile deformation, necessitating a post-processing technique to improve its crystallinity and stability. Here, the structural evolution of pre-stretched PEF under post heating after uniaxial deformation was monitored by online synchrotron X-ray diffraction/scattering, differential scanning calorimetry, and ex situ infrared spectroscopy. The results delineate the significantly enhanced crystallization of pre-deformed PEF that happened far below its cold crystallization temperature. Through the isochronous analyses of the temperature-dependent evolution of mechanical response, the mesophase, crystal structure, orientation factor, chain conformation, and interchain ═C-H···O═C hydrogen bonding, the molecular mechanisms of microstructural transition and oriented crystallization of pre-drawn PEF under post heating were clarified. This research can enhance the understanding of PEF crystallization in an oriented state and provide guidelines on the structural design and technical control for processing high-performance PEF-based materials.
后处理在取向材料最终结构和性能的确定中起着至关重要的作用。作为油基聚对苯二甲酸乙二酯的可持续替代品，生物基聚2,5-呋喃二甲酸乙二酯（PEF）在绿色纤维、薄膜和包装应用中展现出巨大潜力，但在拉伸变形下其应力诱导结晶（SIC）较差，因此需要一种后处理技术来提高其结晶度和稳定性。在此，通过在线同步加速器X射线衍射/散射、差示扫描量热法和非原位红外光谱对单轴变形后预拉伸PEF在后续加热过程中的结构演变进行了监测。结果表明，预变形PEF在远低于其冷结晶温度时发生了显著增强的结晶。通过对力学响应、中间相、晶体结构、取向因子、链构象和链间═C-H···O═C氢键随温度变化的同步分析，阐明了后加热条件下预拉伸PEF微观结构转变和取向结晶的分子机制。本研究可增进对取向状态下PEF结晶的理解，并为高性能PEF基材料的结构设计和工艺控制提供指导。
