可降解塑料聚乳酸共混增韧改性进展

Progress in Blending Modification of Degradable Plastic Poly(lactic acid)

聚乳酸是一种生物可降解聚合物,具有易加工成型、力学强度较高等特点,在生物医疗、纤维纺丝、食品包装等领域中应用广泛。但是,其存在结晶速率较慢、脆性大、耐热性差等缺陷,限制了聚乳酸的工程应用。结合聚合物的可降解性、界面增容、增韧机理等,对近年来聚乳酸共混增韧改性方面的研究进展进行概述,发现,生物基和/或可降解柔性聚合物对聚乳酸增韧改性效果与传统石油基聚合物接近;另外,重点综述了引发剂和扩链剂原位反应增容、纳米粒子增容的界面增容方法、增容机理及特点,并且,简要介绍了共混改性PLA的力学性能及耐热性;阐述了共混增韧改性效果与聚乳酸基体结晶的关系,发现,聚乳酸结晶与柔性聚合物具有协同增韧作用,最后,展望了聚乳酸共混物的应用前景。

Biodegradable polymers have become a research hotspot in the field of materials due to their eco-friendly. Poly(lactic acid)(PLA) is an important component of polymer in ecological environment. PLA is widely used in biomedical, fiber spinning, food packaging and other fields due to its easy processing and excellent mechanical properties. However, there are some disadvantages of PLA such as high brittleness and poor thermal resistance. The biodegradability, interfacial and toughening mechanism of PLA blends are summarized, based on the investigation in the last ten years. Compared to traditional petroleum polymers, PLA materials blended with bio-based and/or degradable flexible polymers have a comparable level of toughness. The interfacial compatibilizing mechanism of initiator and chain extender in situ reaction, nano-particles, and the synergistic toughening relationship between flexible polymer and PLA crystallization are discussed. Finally, the application of PLA blends is proposed.