Phase Morphology, Crystallization Behavior and Mechanical Properties of Poly（L-lactide） Toughened with Biodegradable Polyurethane： Effect of Composition and Hard Segment Ratio

• Published in: 高分子科学：英文版 2015 (9), p.1294-1304
• Main Author: Qian Xing Rong-bo Li Xia Dong Xiu-qin Zhang Liao-yun Zhang Du-jin Wang
• Format: Article
• Language: English
• Subjects: L-乳酸; 可生物降解; 机械性能; 玻璃化转变温度; 相形态; 硬段含量; 结晶行为; 聚氨酯
• ISSN: 0256-7679; 1439-6203

Polyester-based biodegradable polyurethane （PU） with different hard segment ratios was selected to modify the impact toughness of poly（L-lactide） （PLLA）. The influence of blending composition and hard segment ratio of PU on the phase morphology, crystallization behavior and mechanical properties of PLLA/PU blends has been investigated systematically. The results showed that the PU particles were uniformly dispersed in PLLA matrix at a scale from sub- microns to several microns. The glass transition temperature of PU within these blends decreased compared to that of neat PU, but rose slightly with its content and hard segment ratio. The presence of PU retarded the crystallization ability of PLLA, whereas enhanced its elongation at break and impact resistance effectively. As the PU content reaches up to 30 wt%, the phenomenon of brittle-ductile transition occurred, resulting in a rougher fracture surface with the formation of fibril-like structure. Moreover, under the same concentrations, the elongation at break and impact strength of PLLA blends decreased slightly with the increase of hard segment ratio of PU.