环境友好型材料增韧改性聚乳酸研究进展

Research progress on toughening and modification of polylactic acid with environmentally friendly materials

生物基热塑性聚乳酸(PLA)具有高强度、高模量和良好的生物降解性和生物相容性,有望取代部分传统的石油基聚合物.然而,PLA固有的脆性、低热变形温度和相对较高的成本阻碍了其广泛应用.本文简述了聚合物的增韧机理,综述了近年来采用可降解聚酯、生物基弹性体、天然高分子及其衍生物、纳米材料以及目前市售抗冲改性剂等环境友好型材料增韧改性聚乳酸的研究进展.提出了从分子结构设计出发制备出不以牺牲PLA强度为代价,又能提高其韧性的环境友好型材料.该材料与聚乳酸既有较好的界面黏接强度,又能在复合材料发生冲击断裂时引发基体产生空穴-银纹来吸收与转移冲击能.此外,在提高基体韧性的同时还应考虑提高PLA的结晶速率及其结晶度,从而提高复合材料的热变形温度.

Bio-based thermoplastic polyester polylactic acid(PLA) has high strength, high modulus, good biodegradability, and biocompatibility. It is expected to replace some traditional petroleum-based polymers. However,the inherent brittleness, low thermal deformation temperature and relatively high cost of PLA hinder its wide application. In this paper, the toughening mechanism of PLA is briefly described. Then, the research progress of toughening and modifying PLA with environmentally friendly materials such as degradable polyester, bio-based elastomer, natural polymer and its derivatives, nanomaterials and currently available impact modifiers are reviewed. It is proposed to prepare environmentally friendly materials that do not sacrifice the strength of PLA but can improve its toughness from the perspective of molecular structure design. This material has good interface adhesion strength with PLA, and can cause the matrix to generate hole-sliver lines to absorb and transfer impact energy when the composite material undergoes impact fracture. In addition, in order to improve the toughness of the matrix, the crystallization rate and crystallinity of PLA should also be considered to improve the thermal deformation temperature of the composite.