In engineering application area, it has always been a challenge to simultaneously improve flame-retardant performance and crystallization rate of polylactic acid (PLA) biomaterials, thus restricting their extensive application. In this work, a multifunctional additive (4,4′-(phenylphosphoryl)bis(piperazine-4,1-diyl))bis(diphenylphosphine oxide) (PDPO) was successfully synthesized and used to fabricate flame retardant PLA biocomposites. The crystallization behavior, fire safety, mechanical properties and flame retardant mechanisms of PLA biocomposites were studied in detail. The results indicated that PDPO notably improved the crystallization rate and crystallinity of PLA biocomposites. When 4 wt% PDPO was incorporated, PLA/PDPO biocomposites successfully passed UL-94V-0 grade and their LOI values were improved from 19.0% of pure PLA to 29.4%. The introduction of PDPO promoted the premature degradation and carbonization of PLA substrate, and inhibited the transesterification of the PLA during thermal pyrolysis process. Besides, PDPO decomposed and produced the Ph and PO, which efficiently exerted the free radical trapping effect in vapor phase. Therefore, the spread of fire for PLA/PDPO was declined and even self-extinguished. Meanwhile, the low addition of PDPO presented little effect on the mechanical properties of PLA composites. This flame retardant PLA biocomposites showed broad application prospects in emerging fields such as electronic devices, automobiles, and 3D printing materials.

在工程应用领域，同时提高聚乳酸（PLA）生物材料的阻燃性能和结晶速率一直是一个挑战，从而限制了其广泛应用。在这项工作中，成功合成了多功能添加剂（4,4'-（苯基磷酰基）双（哌嗪-4,1-二基））双（二苯基氧化膦）（PDPO）并用于制备阻燃PLA生物复合材料。详细研究了PLA生物复合材料的结晶行为、防火安全、力学性能和阻燃机理。结果表明，PDPO显着提高了PLA生物复合材料的结晶速率和结晶度。当掺入 4 wt% PDPO 时，PLA/PDPO 生物复合材料成功通过了 UL-94V-0 级，其 LOI 值从纯 PLA 的 19.0% 提高到 29.4%。PDPO的引入促进了PLA底物的过早降解和碳化，并抑制了PLA在热解过程中的酯交换。此外，PDPO 分解产生Ph和 PO ，在气相中有效地发挥了自由基捕获作用。因此，PLA/PDPO 的火势蔓延被抑制甚至自熄。同时，低添加量的 PDPO 对 PLA 复合材料的力学性能影响不大。这种阻燃PLA生物复合材料在电子设备、汽车、3D打印材料等新兴领域显示出广阔的应用前景。