Roles of phosphoramide derivatives in flame retardancy, thermal degradation and crystallization behaviors of polylactic acid.
Roles of phosphoramide derivatives in flame retardancy, thermal degradation and crystallization behaviors of polylactic acid.
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DOI：
10.1016/j.ijbiomac.2022.07.172
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发表时间：
2022-07
影响因子：
8.2
通讯作者：
Xu Hu;Bingtao Wang;Zhenghong Guo;Zhengping Fang;Peng Chen;Juan Li
中科院分区：
文献类型：
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作者：
Xu Hu;Bingtao Wang;Zhenghong Guo;Zhengping Fang;Peng Chen;Juan Li
以二苯膦酰氯、苯基膦酰氯和糠胺为原料，分别合成了两种含一个（POFA）和两个（BPOFA）磷酰胺键的磷酰胺衍生物。采用极限氧指数（LOI）、UL-94垂直燃烧试验、锥形量热仪、热重分析和差示扫描量热法研究了聚乳酸（PLA）/POFA和PLA/BPOFA共混物的阻燃性能、热降解和结晶行为。少量的1.0重量%的BPOFA将PLA的LOI从20.4体积%增加到28.0体积%并达到UL-94 V0等级，而需要7.0重量%的POFA才能达到UL-94 V0等级，表明PLA/BPOFA具有比PLA/POFA更好的阻燃性。POFA和BPOFA均能降低聚乳酸酯交换反应中可燃气体的生成量，对聚乳酸酯交换反应有积极的促进作用。更重要的是，BPOFA更容易催化PLA的降解，并通过熔融方式提高UL-94等级。BPOFA的加入加快了PLA的结晶速率，提高了PLA的结晶度，而POFA对PLA的结晶行为没有明显的促进作用。
Two kinds of phosphoramide derivatives containing one (POFA) or two (BPOFA) phosphoramide bonds were synthesized using diphenylphosphinic chloride, phenylphosphonic dichloride and furfurylamine, respectively. The flame retardancy, thermal degradation and crystallization behaviors of polylactic acid (PLA)/POFA and PLA/BPOFA blends were investigated using the limiting oxygen index (LOI), UL-94 vertical burning tests, cone calorimeter tests, thermogravimetric analysis and differential scanning calorimetry. A small amount of 1.0 wt% BPOFA increases the LOI of PLA from 20.4 vol% to 28.0 vol% and achieves the UL-94 V0 rating, while 7.0 wt% POFA is needed to achieve the UL-94 V0 rating indicating that the PLA/BPOFA has better flame retardancy than that of PLA/POFA. Both POFA and BPOFA decrease the amount of flammable gaseous compounds and play positive roles in transesterification of PLA. More importantly, BPOFA is easier to catalyze the degradation of PLA and improve UL-94 rating by melting-away mode. Moreover, the BPOFA accelerates the crystallization rate and thus improves the crystallinity of PLA, while POFA does not show a positive effect on crystallization behaviors of PLA.