Toughening of polylactide by melt blending with a biodegradable poly(ether)urethane elastomer
Toughening of polylactide by melt blending with a biodegradable poly(ether)urethane elastomer
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DOI：
10.1002/mabi.200700027
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发表时间：
2007-07-09
影响因子：
4.6
通讯作者：
Shimizu, Hiroshi
中科院分区：
文献类型：
--
作者：
Li, Yongjin;Shimizu, Hiroshi
为了在不影响聚乳酸的生物降解性和生物相容性的前提下增韧聚乳酸，采用熔融共混法将聚乳酸与可生物降解的聚醚氨基甲酸酯(PU)共混。研究了共混物的相容性能、相形态、力学性能和增韧机理。动态力学分析表明，该共混物为部分相容体系，玻璃化转变温度发生变化。PU弹性体分散在聚乳酸基质中，微区尺寸为亚微米级。PU弹性体的加入不仅加快了聚乳酸的结晶速度，而且降低了聚乳酸的结晶度。随着PU含量的增加，共混物的拉伸强度和定伸应力降低，而断裂伸长率和冲击强度显著提高，表明PU弹性体对聚乳酸具有增韧作用。随着PU弹性体的加入，聚乳酸的脆性断裂逐渐转变为延性断裂。拉伸和冲击试验发现，共混物中的聚乳酸基体表现出大面积的塑性变形(剪切屈服)，这是一个重要的能量耗散过程，导致了增韧的、可生物降解的聚合物共混物。
Melt blending of polylactide (PLA) and a biodegradable poly(ether)urethane (PU) elastomer has been performed in an effort to toughen the polylactide without compromising its biodegradability and biocompatibility. The miscibility, phase morphology, mechanical properties, and toughening mechanism of the blend were investigated. The blend was found by dynamic mechanical analysis to be a partially miscible system with shifted glass transition temperatures. The PU elastomer was dispersed in the PLA matrix with a domain size of sub‐micrometer scale. The addition of PU elastomer not only accelerated the crystallization speed, but also decreased the crystallinity of the PLA. With an increase in PU content, the blend shows decreased tensile strength and modulus; however, the elongation at break and the impact strength were significantly increased, indicating the toughening effects of the PU elastomer on the PLA. The brittle fracture of neat PLA was gradually transformed into ductile fracture by the addition of PU elastomer. It was found that the PLA matrix demonstrates large area, plastic deformation (shear yielding) in the blend upon being subjected the tensile and impact tests, which is an important energy‐dissipation process and leads to a toughened, biodegradable polymer blend.