Abstract Due to the environmental pollution caused by the petroleum-based polymer, poly (lactic acid) (PLA), a biodegradable and biocompatible polymer that obtained from natural and renewable sources, has attracted widespread attention. However, the brittleness of PLA greatly limits its application. In this study, the super toughened PLA-based blends were obtained by compatibilizing the PLA/thermoplastic polyurethane (TPU) blends with the polyurethane elastomer prepolymer (PUEP) as an active compatibilizer. The mechanical properties, thermal properties and corresponding toughening mechanism of PLA/TPU/PUEP system were studied by tensile test, instrumented impact test, dynamic mechanical analysis (DMA), scanning electronic microscope (SEM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). All the results demonstrate that the isocyanate (−NCO) group in PUEP is successfully reacted with the –OH groups at both sides of the PLA and the obtained polyurethane (PU)~PLA copolymer (PU ~ co PLA) significantly improves the interfacial compatibility of PLA/TPU blends. The gradually refined dispersed phase size and fuzzy phase interface as displayed in SEM images suggest a good interfacial compatibilization in the PLA/TPU/PUEP blends, probably due to the isocyanate reaction between PLA and PUEP. And the interfacial reaction and compatibilization among the components led to the formation of super toughened PLA/TPU/PUEP blends. And the instrumented impact results indicate that most of the impact toughness is provided by the crack propagation rather than the crack initiation during the entire fracture process.

中文翻译：

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通过提高聚氨酯弹性体预聚物的界面相容性及其增韧机制来提高聚（乳酸）/热塑性聚氨酯共混物的韧性

摘要 由于石油基聚合物对环境造成的污染，聚乳酸（PLA）是一种从天然和可再生资源中提取的可生物降解和生物相容性聚合物，受到广泛关注。然而，PLA的脆性极大地限制了其应用。在这项研究中，通过将 PLA/热塑性聚氨酯 (TPU) 共混物与作为活性增容剂的聚氨酯弹性体预聚物 (PUEP) 相容，获得了超韧 PLA 基共混物。通过拉伸试验、仪器化冲击试验、动态力学分析(DMA)、扫描电子显微镜(SEM)、差示扫描量热法(DSC)和热重分析研究了PLA/TPU/PUEP体系的力学性能、热性能和相应的增韧机理。 (TGA)。所有结果表明，PUEP中的异氰酸酯（-NCO）基团与PLA两侧的-OH基团成功反应，得到的聚氨酯（PU）~PLA共聚物（PU~co PLA）显着提高了其界面相容性。 PLA/TPU 混合物。SEM 图像中显示的逐渐细化的分散相尺寸和模糊的相界面表明 PLA/TPU/PUEP 共混物具有良好的界面相容性，这可能是由于 PLA 和 PUEP 之间的异氰酸酯反应。并且组分之间的界面反应和增容导致超韧PLA/TPU/PUEP共混物的形成。仪器化的冲击结果表明，在整个断裂过程中，大部分冲击韧性是由裂纹扩展而不是裂纹萌生提供的。