“Dual-purpose” strategy of achieving fire safety and UV-resistance of polylactic acid

Flame-retardant properties are crucial for polylactic acid (PLA) used in packaging, electrical, and agricultural applications. However, PLA is susceptible to degradation from ultraviolet (UV) light, limiting its longevity. This necessitates the development of PLA composites with improved flame-retardant and UV-resistant properties. Here, we synthesized a multifunctional core–shell spherical flame-retardant TA@HPDT, employing tannic acid (TA) for its effective free radical trapping capability. TA@HPDT was incorporated into PLA to enhance fire safety and UV resistance. The PLA-2 % TA@HPDT composite exhibited exceptional flame-retardant efficiency, achieving a UL-94 V-0 rating and a limiting oxygen index of 25.6. Furthermore, the addition of TA@HPDT reduced the peak heat release rate and total heat release by 16.8 % and 16.7 %, respectively. After 100 h of UV aging, the PLA composite retained 93.3 % of its mass, indicating significantly improved UV resistance. This study demonstrates a strategic approach to developing PLA composites that enhance fire performance and extend service life.