Sun Mingtao, Huang Shuang, Yu Muhuo, Han Keqing
College of Materials Science and Engineering, Donghua University, Shanghai 201620, China.
Polymers (Basel). 2021 Jun 11;13(12):1953. doi: 10.3390/polym13121953.
The melt blending of polylactic acid (PLA) and thermoplastic silicone polyurethane (TPSiU) elastomer was performed to toughen PLA. The molecular structure, crystallization, thermal properties, compatibility, mechanical properties and rheological properties of the PLA/TPSiU blends of different mass ratios (100/0, 95/5, 90/10, 85/15 and 80/20) were investigated. The results showed that TPSiU was effectively blended into PLA, but no chemical reaction occurred. The addition of TPSiU had no obvious effect on the glass transition temperature and melting temperature of PLA, but slightly reduced the crystallinity of PLA. The morphology and dynamic mechanical analysis results demonstrated the poor thermodynamic compatibility between PLA and TPSiU. Rheological behavior studies showed that PLA/TPSiU melt was typically pseudoplastic fluid. As the content of TPSiU increased, the apparent viscosity of PLA/TPSiU blends showed a trend of rising first and then falling. The addition of TPSiU had a significant effect on the mechanical properties of PLA/TPSiU blends. When the content of TPSiU was 15 wt%, the elongation at break of the PLA/TPSiU blend reached 22.3% (5.0 times that of pure PLA), and the impact strength reached 19.3 kJ/m (4.9 times that of pure PLA), suggesting the favorable toughening effect.
为了增韧聚乳酸（PLA），进行了聚乳酸与热塑性有机硅聚氨酯（TPSiU）弹性体的熔融共混。研究了不同质量比（100/0、95/5、90/10、85/15和80/20）的PLA/TPSiU共混物的分子结构、结晶、热性能、相容性、力学性能和流变性能。结果表明，TPSiU有效地共混到PLA中，但未发生化学反应。TPSiU的加入对PLA的玻璃化转变温度和熔点没有明显影响，但略微降低了PLA的结晶度。形态和动态力学分析结果表明PLA与TPSiU之间的热力学相容性较差。流变行为研究表明，PLA/TPSiU熔体为典型的假塑性流体。随着TPSiU含量的增加，PLA/TPSiU共混物的表观粘度呈先上升后下降的趋势。TPSiU的加入对PLA/TPSiU共混物的力学性能有显著影响。当TPSiU含量为15 wt%时，PLA/TPSiU共混物的断裂伸长率达到22.3%（是纯PLA的5.0倍），冲击强度达到19.3 kJ/m（是纯PLA的4.9倍），表明增韧效果良好。
