The use of biodegradable polymers such as Poly (lactic acid) (PLA), Poly(butylene succinate) (PBS), and Poly(butylene adipate--terephthalate) (PBAT) is constantly increasing to try to substitute non-biodegradable plastics. Blending is a viable option to improve the morphology and the mechanical and heat resistance properties of biodegradable polymers. Thus, in this work, a biodegradable and compostable PLA/PBAT blend was improved by adding PBS, leading to non-reactive, melt-mixed PLA/PBAT/PBS ternary blends. The PLA/PBAT ratio was fixed at 1:1, while the PBS varied from 0 to 40 wt%. Polarized Light Optical Microscopy (PLOM) imaging showed that micro-spherulitic PBS was localized at the interface between PLA and PBAT in the blend, acting as a compatibilizer, reducing the interfacial tension and refining the ternary blend's morphology. Consequently, the mechanical properties improved, such as the elongation at break, which increased from 70 to 300 %. However, these tertiary non-reactive blends were found to lack adequate rheological properties to be processed by blown film extrusion. Therefore, reactive blending was performed by adding peroxide and carbodiimide, leading to a finer morphology and improved rheological properties. Thus, these reactive blends were successfully processed by blown film extrusion. Two types of blown films were produced, Tubular and Champagne films (DDR/BUR ratio of 37.6 and 5.2, respectively). Both types of blown films exhibited adequate ductile mechanical properties for film packaging applications, as well as high seal strength and good thermal resistance. In addition, their specific mechanical properties were a function of blend composition and the degree of biaxial orientation produced during the extrusion-blowing process.

中文翻译：

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配制用于可生物降解、可堆肥包装的 PBS/PLA/PBAT 混合物：PBS 含量和反应挤出的关键作用

聚乳酸（PLA）、聚丁二酸丁二醇酯（PBS）和聚己二酸对苯二甲酸丁二醇酯（PBAT）等可生物降解聚合物的使用不断增加，试图替代不可生物降解的塑料。共混是改善可生物降解聚合物的形态以及机械和耐热性能的可行选择。因此，在这项工作中，通过添加 PBS 改进了可生物降解和可堆肥的 PLA/PBAT 混合物，从而形成非反应性熔融混合的 PLA/PBAT/PBS 三元混合物。PLA/PBAT 比例固定为 1:1，而 PBS 在 0 至 40 wt% 之间变化。偏光光学显微镜（PLOM）成像显示，微球状PBS位于共混物中PLA和PBAT之间的界面处，充当增容剂，降低界面张力并细化三元共混物的形态。因此，机械性能得到改善，例如断裂伸长率从 70% 增加到 300%。然而，这些三级非反应性共混物被发现缺乏通过吹膜挤出加工所需的足够的流变性能。因此，通过添加过氧化物和碳二亚胺进行反应共混，从而获得更精细的形貌和改善的流变性能。因此，这些反应性共混物成功地通过吹膜挤出加工。生产了两种类型的吹塑薄膜：管状薄膜和香槟薄膜（DDR/BUR 比率分别为 37.6 和 5.2）。两种类型的吹塑薄膜都表现出适合薄膜包装应用的足够的延展性机械性能，以及高密封强度和良好的耐热性。此外，它们的具体机械性能是共混物组成和挤出吹塑过程中产生的双轴取向程度的函数。