This study tackles the challenge of improving both barrier and mechanical properties in biodegradable PBS/PLLA blends, which typically suffer from phase separation and the low-barrier performance of PLLA. By introducing a novel "Slit Extrusion-Hot Stretching-Quench-Compression" technique, the research offers a systematic investigation of how controlling the stretch ratio in an extensional flow affects the morphology and structure of the film. Using advanced techniques like synchrotron radiation small-angle X-ray scattering (SAXS), wide-angle X-ray diffraction (WAXD), dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM), the study demonstrates that PLLA nanofibers with high crystallinity can be in-situ generated when stretch ratios exceed 3. These nanofibers provide a tortuous pathway and confinement effect to boost the film’s tensile strength (15% strength increase), and modulus properties (300% elastic modulus boost), as well as enhance its oxygen barrier by 33%. This innovative approach creates a nanostructured film that enhances interphase interaction and gas permeability tortuosity without the need for nanoparticles, paving the way for the practical fabrication of optimized biodegradable polymer blends at scale.

中文翻译：

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通过形成原位纳米原纤化增强 PBS/PLLA 阻隔膜的阻隔性能


本研究解决了改善可生物降解 PBS/PLLA 混合物的阻隔性和机械性能的挑战，这些混合物通常受到相分离和 PLLA 的低阻隔性能的影响。通过引入一种新颖的“狭缝挤出-热拉伸-淬火-压缩”技术，该研究系统地研究了控制拉伸流中的拉伸比如何影响薄膜的形态和结构。利用同步辐射小角 X 射线散射 （SAXS）、广角 X 射线衍射 （WAXD）、动态力学分析 （DMA）、差示扫描量热法 （DSC） 和扫描电子显微镜 （SEM） 等先进技术，该研究表明，当拉伸比超过 3 时，可以原位生成具有高结晶度的 PLLA 纳米纤维。这些纳米纤维提供曲折的路径和限制效应，以提高薄膜的拉伸强度（强度增加 15%）和模量性能（弹性模量增加 300%），并将其氧阻隔性提高 33%。这种创新方法创造了一种纳米结构膜，无需纳米颗粒即可增强相间相互作用和透气性弯曲，为大规模实际制造优化的可生物降解聚合物混合物铺平了道路。