Conventional petroleum-based plasticizers not only exhibit reproductive toxicity and non-biodegradability, but their introduction also makes plastics highly combustible. Therefore, the development of biodegradable flame-retardant plasticizers derived from biomass resources can effectively solve the matters mentioned above. In this work, we developed a new l-lactic acid-based biodegradable flame-retardant plasticizer containing phosphorus, nitrogen, and silicon elements (PDL550) with flame-retarded, smoke-suppressing, and plasticized function. The introduction of PDL550 can simultaneously enhance the flame-retardant and flexible performances of polylactic acid (PLA). With the addition of 20 phr PDL550, the PDL550-plasticized PLA blends could pass a UL-94 V-0 grade, and simultaneously its elongation at break increased to 290.32 % in comparison with that of pure PLA (3.70 %). The cone calorimetric tests exhibited that the peak of heat release rate and total heat release of PDL550-plasticized PLA blends, in comparison with that of pure PLA, decreased by 17.8 and 50.8 %, respectively. By analyzing the volatiles and the residual char layer, the phosphorus and silicon elements synergistically in PDL550 are conducive to facilitating the formation of the complete and dense char layer, thus suppressing the release of smoke and shielding the attack of heat. Interestingly, the active soil and tenebrio molitors experiments exhibited that the PDL550 chain was attacked by microbes to form a small aliphatic molecule structure, indicating the excellent biodegradability of PDL550. This study provides an essential reference for developing bio-derived fire-retardant plasticizers to enhance fire safety, smoke-suppressing, and flexible PLA composites.

中文翻译：

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绿色可生物降解乳酸基阻燃增塑剂的制备同时增强聚乳酸的柔韧性、阻燃性和抑烟性


传统的石油基增塑剂不仅表现出生殖毒性和不可生物降解性，而且它们的引入也使塑料高度易燃。因此，开发源自生物质资源的可生物降解阻燃增塑剂可以有效解决上述问题。本工作开发了一种新型含磷、氮、硅元素的L-乳酸基可生物降解阻燃增塑剂（PDL550），具有阻燃、抑烟、增塑功能。 PDL550的引入可以同时增强聚乳酸（PLA）的阻燃和柔韧性能。添加 20 份 PDL550 后，PDL550 增塑的 PLA 共混物可以通过 UL-94 V-0 级，同时其断裂伸长率比纯 PLA (3.70%) 增加到 290.32%。锥形量热测试表明，与纯PLA相比，PDL550增塑PLA共混物的放热速率峰值和总放热量分别降低了17.8%和50.8%。通过对挥发物和残留炭层的分析，PDL550中的磷和硅元素协同作用，有利于促进形成完整致密的炭层，从而抑制烟雾的释放，屏蔽热的侵袭。有趣的是，活性土壤和黄粉虫实验表明，PDL550链被微生物攻击，形成脂肪族小分子结构，表明PDL550具有优异的生物降解性。该研究为开发生物源阻燃增塑剂以增强防火安全、抑烟和柔性PLA复合材料提供了重要参考。