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

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.