A new strategy for the preparation of polylactic acid composites with flame retardancy, UV resistance, degradation, and recycling performance

Polylactic acid (PLA) is one of the solutions to the white pollution and energy crisis. However, the using performance (such as flame retardant, weather resistance and mechanical properties) and recycling performance limit its wide application. In this work, a bio-based additive (PA-Fe-HBT) with core–shell structure is synthesized by tannins microspheres and phytic acid (PA). By the presence of 3 wt% PA-Fe-HBT, the limited oxygen index is increased to 25.5%, and the sample can pass UL-94 V-0 grade. At the same time, the mechanical properties of the composites remain good. Besides, the ultraviolet aging resistance and ultraviolet protection ability of the composite are significantly improved. The ultraviolet (UV) transmittance of PLA/3%PA-Fe-HBT sample shows a decrease of 99.97% compared with control PLA. More importantly, the chemical recycling of composites is promoted by PA-Fe-HBT in the absence of external heating. After a simple purification, 88% purity of lactic acid is obtained. It is believed that this work proposes an ingenious design strategy to prepare PLA/PA-Fe-HBT composites with flame-retardancy, UV resistance and chemical recycling performances.