Simultaneously enhancing the fire retardancy and crystallization rate of biodegradable polylactic acid with piperazine-1,4-diylbis (diphenylphosphine oxide)
Simultaneously enhancing the fire retardancy and crystallization rate of biodegradable polylactic acid with piperazine-1,4-diylbis (diphenylphosphine oxide)
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1,4-二基双哌嗪（二苯基氧化膦）同时提高可生物降解聚乳酸的阻燃性和结晶速率
DOI：
10.1016/j.compositesb.2020.108407
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发表时间：
2020-12-01
影响因子：
13.1
通讯作者：
Li, Bin
中科院分区：
文献类型：
--
作者：
Liu, Lubin;Xu, Yue;Li, Bin
同时提高聚乳酸的阻燃性能和结晶速率一直是工程应用领域面临的挑战。本文以二苯基氯化膦和哌嗪为原料，合成了一种哌嗪-磷酰胺衍生物(PPDO)，并对其化学结构进行了确证。PPDO作为一种多功能助剂，同时提高了聚乳酸的防火安全性和结晶速率。系统研究了聚乳酸生物复合材料的阻燃性能、结晶行为、力学性能及阻燃机理。当PPDO的掺入量仅为3wt%时，聚乳酸生物复合材料达到了UL-94 V-0等级，氧指数为27.8%。PPDO在聚乳酸中的优异阻燃作用归因于凝聚相中致密致密的炭层的屏蔽作用，以及气相中含苯、磷自由基的抑制作用和惰性气体的稀释作用。因此，聚乳酸生物复合材料的有效热燃烧和总放热受到显著抑制。同时，PPDO是聚乳酸的良好成核剂，有效地提高了聚乳酸的结晶度和结晶速率。此外，聚乳酸生物复合材料由于PPDO的低加入量以及与聚乳酸基质良好的相容性，仍然保持了优异的透明性和力学性能，这使得阻燃聚乳酸生物复合材料在先进光电子器件领域具有巨大的应用前景。
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.