Novel Dihydroxy-Containing Ammonium Phosphate Based Poly(Lactic Acid): Synthesis, Characterization and Flame Retardancy
Novel Dihydroxy-Containing Ammonium Phosphate Based Poly(Lactic Acid): Synthesis, Characterization and Flame Retardancy
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新型含二羟基磷酸铵基聚乳酸：合成、表征和阻燃性
DOI：
10.3390/polym10080871
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发表时间：
2018-08-01
期刊：
影响因子：
5
通讯作者：
Wang, De-Yi
中科院分区：
文献类型：
--
作者：
Jian, Rong-Kun;Xia, Long;Wang, De-Yi
本工作的目的是通过掺入源自2-氯-5,5-二甲基-1,3,2-二氧膦烷-2-氧化物(DOP)和2-氨基-2-甲基-1,3-丙二醇(AMPD)的新型阻燃剂二羟基磷酸铵(DAP)来制备阻燃生物基聚乳酸材料。有趣的是，仅添加0.5% DAP的PLA改性物就通过了UL-94 V-0等级，其极限氧指数（LOI）值为24.6%，并且随着DAP负载量的增加，该值还会进一步增加。 PLA/DAP 在热释放速率（HRR）方面没有表现出明显的改善结果，因为 DAP 的负载量相对较低。结果发现，DAP 对 PLA 的热稳定性影响很小，并且 PLA 和 PLA/DAP 共混物的起始分解温度非常接近。此外，由于DAP的增塑作用，结晶度增加。通过对DAP阻燃机理的分析，揭示了DAP分解生成水、氨等不燃化合物，稀释氧气和燃料的浓度，然后释放出一些含磷碎片，产生含磷自由基，中断自由基反应，最后产生不燃熔体滴落，带走大量热量，阻止热量向基体反馈。
The aim of this work is to prepare flame-retardant biobased poly(lactic acid) materials through incorporating a novel flame retardant dihydroxy-containing ammonium phosphate (DAP) derived from 2-chloro-5,5-dimethyl-1,3,2-dioxaphosphinane-2-oxide (DOP) and 2-amino-2-methyl-1,3-propanediol (AMPD). Interestingly, PLA modified with only 0.5% DAP passed UL-94 V-0 rating, and possessed a limiting oxygen index (LOI) value of 24.6%, which would further increase with the increasing loading of DAP. PLA/DAP did not exhibit obviously improved results in terms of heat release rate (HRR), as the loading of DAP was relatively low. It was found that DAP showed little effect on the thermal stability of PLA and the onset decomposition temperatures of PLA and PLA/DAP blends were very close. Besides, the degree of crystallization increased because of the plasticized effect of DAP. Based on the analyses of flame-retardant mechanism of DAP, it disclosed that DAP decomposed to generate incombustible compounds, such as water and ammonia, to dilute the concentration of oxygen and fuels, and then release some phosphorus-containing fragments that could produce phosphorus-containing free radicals to interrupt free-radical reactions, and finally noncombustible melt dripping was produced so as to bring away large amount of heat and stop the feedback of heat to the matrix.