Improvement in toughness of polylactide by melt blending with bio-based poly(ester)urethane
Improvement in toughness of polylactide by melt blending with bio-based poly(ester)urethane
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DOI：
10.1007/s10118-014-1487-9
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发表时间：
2014-06
影响因子：
4.3
通讯作者：
Ruilei Yu;Lisheng Zhang;Yu-hong Feng;Ruoyu Zhang;Jin Zhu
中科院分区：
文献类型：
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作者：
Ruilei Yu;Lisheng Zhang;Yu-hong Feng;Ruoyu Zhang;Jin Zhu
以生物质二醇和二元酸为原料合成生物基聚酯软段，与含有生物基聚(酯)氨酯(TPU)弹性体的共混物共混，成功地增韧了聚乳酸。研究了共混物的相容性能、力学性能、相形态及增韧机理。DSC和DMTA结果表明，TPU弹性体的加入不仅加快了结晶速度，而且提高了最终结晶度，证明了TPU与聚乳酸的相容性有限，具有增塑作用。扫描电子显微镜观察表明，共混物均表现出明显的海岛结构相分离现象，且随着TPU含量的增加，共混物中的橡胶颗粒尺寸增大。聚乳酸/热塑性聚氨酯共混物的力学性能变化可用吴氏模型定量解释。随着TPU含量的变化，TPU/PLA共混物发生了脆韧转变。当共混物处于拉应力状态时，共混物中的TPU粒子可以从聚乳酸基体中剥离，在断裂前表现出较强的诱导大范围塑性变形的能力，这对断裂能的耗散具有重要意义。拉伸试验和扫描电子显微镜(SEM)观察证实了这一机理。
Polylactide (PLA) was successfully toughened by blending with bio-based poly(ester)urethane (TPU) elastomers which contained bio-based polyester soft segments synthesized from biomass diols and diacids. The miscibility, mechanical properties, phase morphology and toughening mechanism of the blend were investigated. Both DSC and DMTA results manifested that the addition of TPU elastomer not only accelerated the crystallization rate, but also increased the final degree of crystallinity, which proved that TPU has limited miscibility with PLA and has functioned as a plasticizer. All the blend samples showed distinct phase separation phenomenon with sea-island structure under SEM observation and the rubber particle size in the PLA matrix increased with the increased contents of TPU. The mechanical property variation of PLA/TPU blends could be quantitatively explained by Wu’s model. With the variation of TPU, a brittle-ductile transition has been observed for the TPU/PLA blends. When these blends were under tensile stress conditions, the TPU particles could be debonded from the PLA matrix and the blends showed a high ability to induce large area plastic deformation before break, which was important for the dissipation of the breaking energy. Such mechanism was demonstrated by tensile tests and scanning electron microcopy (SEM) observations.