Polylactic acid (PLA) was regarded as the most prospective sustainable bioplastic in the field of engineering applications, but its slow crystallization and strong sensitivity to fire severely restrict its large-scale applications. In this research, a multi-functional additive N,N',N''-(nitrilotris(ethane-2,1-diyl))tris(P,P-diphenylphosphinic amide) (NTPA) was successfully synthesized through the substitution reaction of N,N-bis(2-aminoethyl)ethylenediamine and diphenylphosphinyl chloride and its chemical structure was determined. NTPA was introduced into PLA to simultaneously enhance the fire safety and crystallization rate of PLA composites and the corresponding crystallization behaviors, fire retardancy, flame retarded mechanism and mechanical performance of PLA composites were systematically investigated. With the introduction of mere 2.5 wt% NTPA, the PLA/NTPA composites gained UL-94 V-0 grade and its LOI reached 28.5%. The remarkable fire safety of PLA/NTPA composites was mainly assigned to the inhibition function of benzene and phosphooxygen radicals generated from the pyrolysis of NTPA and the dilution effect of inert gases in gas phase. Besides, an uniform and compact char layer exerted a certain barrier effect in condensed phase. Thus, the total heat release and average effective heat combustion of PLA/NTPA composites were evidently declined by 12.2 and 9.8% and the flame retardant index was increased by 38% with only 2.5 wt% NTPA loading. Meanwhile, NTPA was a good nucleating agent for PLA matrix and efficiently enhanced the crystallinity and crystallization rate of PLA. Interestingly, PLA/NTPA composites still retained superior transparency and mechanical properties. This flame-retardant PLA composites exhibited the enormous application prospect in the field of advanced optoelectronic devices.

聚乳酸（PLA）被认为是工程应用领域中最有前途的可持续生物塑料，但是其缓慢的结晶和对火的强烈敏感性严重限制了其大规模应用。在本研究中，通过取代反应成功地合成了多功能添加剂N，N'，N''-（硝化腈（乙烷-2,1-二基））三（P，P-二苯基次膦酰胺）（NTPA）。测定了N，N-双（2-氨基乙基）乙二胺和二苯基次膦酰氯及其化学结构。将NTPA引入PLA，以同时提高PLA复合材料的防火安全性和结晶速率，并系统研究了PLA复合材料的相应结晶行为，阻燃性，阻燃机理和力学性能。通过仅引入2.5 wt％的NTPA，PLA / NTPA复合材料获得了UL-94 V-0等级，其LOI达到28.5％。PLA / NTPA复合材料出色的防火性能主要归因于NTPA热解产生的苯和磷氧自由基的抑制功能以及气相中惰性气体的稀释作用。此外，均匀而致密的炭层在凝结相中发挥了一定的阻挡作用。因此，仅NTPA负载量为2.5 wt％时，PLA / NTPA复合材料的总热量释放和平均有效热燃烧率分别下降了12.2和9.8％，阻燃指数提高了38％。同时，NTPA是PLA基质的良好成核剂，有效提高了PLA的结晶度和结晶速率。有趣的是 PLA / NTPA复合材料仍保留了优异的透明度和机械性能。这种阻燃的PLA复合材料在先进的光电器件领域具有广阔的应用前景。