The simultaneous improvement of flame retardancy and crystallization rate for polylactic acid (PLA) has always been a challenge in the field of engineering applications. In this paper, a piperazine-phosphamide derivative (PPDO) was successfully synthesized from diphenylphosphinyl chloride and piperazine and its chemical structure was confirmed. The PPDO was served as a multi-functional additive to simultaneously improve the fire safety and crystallization rate of PLA. The fire retardancy, crystallization behaviors, mechanical properties and flame-retardant mechanism of PLA biocomposites were systematically investigated. With the incorporation of mere 3 wt% PPDO, the PLA biocomposites fulfilled UL-94 V-0 rating with the LOI of 27.8%. The outstanding fire retardancy of PPDO in PLA was ascribed to the shielding effect of compact and dense char layer in condensed phase, and the suppression function of benzene- and phosphorus-containing free radicals and the dilution role of inert gases in vapor phase. Thus, the effective heat combustion and total heat release of PLA biocomposites were prominently depressed. Meanwhile, PPDO was a good nucleating agent for PLA, which effectively increased the crystallinity and crystallization rate of PLA. Besides, PLA biocomposites still maintained remarkable transparency and mechanical properties due to the low addition of PPDO and excellent compatibility with the PLA matrix, which endowed flame-retardant PLA biocomposites with the enormous application prospect in the field of advanced optoelectronic devices.

聚乳酸（PLA）的阻燃性和结晶速率的同时提高一直是工程应用领域中的挑战。本文成功地从二苯基次膦酰氯和哌嗪合成了哌嗪磷酰胺衍生物（PPDO），并确定了其化学结构。PPDO用作多功能添加剂，可同时提高PLA的防火安全性和结晶速率。系统地研究了PLA生物复合材料的阻燃性，结晶行为，力学性能和阻燃机理。仅掺入3 wt％的PPDO，PLA生物复合材料即可达到UL-94 V-0等级，LOI为27.8％。PPDO在聚乳酸中的出色阻燃性归因于在致密相中致密致密炭层的屏蔽作用，对苯和磷自由基的抑制作用以及惰性气体在气相中的稀释作用。因此，显着降低了PLA生物复合材料的有效热燃烧和总热量释放。同时，PPDO是PLA的良好成核剂，有效提高了PLA的结晶度和结晶速率。此外，由于PPDO的添加量少，并且与PLA基体具有优异的相容性，因此PLA生物复合材料仍保持出色的透明度和机械性能，这为阻燃PLA生物复合材料在先进的光电器件领域具有广阔的应用前景。含苯和磷的自由基的抑制功能以及惰性气体在气相中的稀释作用。因此，显着降低了PLA生物复合材料的有效热燃烧和总热量释放。同时，PPDO是PLA的良好成核剂，有效提高了PLA的结晶度和结晶速率。此外，由于PPDO的添加量少，并且与PLA基体具有优异的相容性，因此PLA生物复合材料仍保持出色的透明度和机械性能，这为阻燃PLA生物复合材料在先进的光电器件领域具有广阔的应用前景。含苯和磷的自由基的抑制功能以及惰性气体在气相中的稀释作用。因此，显着降低了PLA生物复合材料的有效热燃烧和总热量释放。同时，PPDO是PLA的良好成核剂，有效提高了PLA的结晶度和结晶速率。此外，由于PPDO的添加量少，并且与PLA基体具有优异的相容性，因此PLA生物复合材料仍保持出色的透明度和机械性能，这为阻燃PLA生物复合材料在先进的光电器件领域具有广阔的应用前景。PLA生物复合材料的有效热燃烧和总热量释放显着下降。同时，PPDO是PLA的良好成核剂，有效提高了PLA的结晶度和结晶速率。此外，由于PPDO的添加量少，并且与PLA基体具有优异的相容性，因此PLA生物复合材料仍保持出色的透明度和机械性能，这为阻燃PLA生物复合材料在先进的光电器件领域具有广阔的应用前景。PLA生物复合材料的有效热燃烧和总热量释放显着下降。同时，PPDO是PLA的良好成核剂，有效提高了PLA的结晶度和结晶速率。此外，由于PPDO的添加量少，并且与PLA基体具有优异的相容性，因此PLA生物复合材料仍保持出色的透明度和机械性能，这为阻燃PLA生物复合材料在先进的光电器件领域具有广阔的应用前景。