A hybrid flame retardant, of excellent stability in aqueous media, was designed to develop flame-retarded polyethyleneimine (PEI) foam. In this case, iron phosphonate (FeP) with carboxyl group and hydroxyl group was first designed and synthesized. The carboxyl group could be hydrogen bonded with the water-soluble ammonium polyphosphate (APP) in aqueous media, and then dispersed as nano-sized particles. Subsequently, the well-dispersed nano-hybrid of FeP and APP (FeP/APP) was blended with hydrophilic PEI to prepare a kind of composite foam through a freeze-drying process. For FeP/APP, the transition metal iron showed excellent catalytic carbonization performances. Meanwhile, APP could also catalyze the degradation of polymers to form a protective char layer. The thermogravimetric analysis coupled with Fourier transform infrared analysis (TG-FTIR) test disclosed that the improvement of flame retardancy for PEI-based foams was ascribed to the synergistic effect of FeP and APP in the condensed phase. The composite foam containing 30 wt% FeP/APP could self-extinguish and reach V-1 rating in UL-94 test. When the loading level of 45% FeP/APP reached 45%, the composite foam could elevate up to V-0 rating, and the peak of heat release rate and total heat release were reduced by 71.8% and 74.2%, respectively, compared to a neat PEI foam. It is worth noting that our work presents a promising way for preparation of stable aqueous flame retardant, and is expected to enhance the fire safety of aqueous foams, coatings, cotton textiles, and other flammable materials.

中文翻译：

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膦酸铁与聚磷酸铵对聚乙烯亚胺基泡沫的水杂化协同阻燃性

设计了一种在水性介质中具有出色稳定性的混合阻燃剂，用于开发阻燃的聚乙烯亚胺（PEI）泡沫。在这种情况下，首先设计并合成具有羧基和羟基的膦酸铁（FeP）。羧基可以在水性介质中与水溶性聚磷酸铵（APP）氢键结合，然后分散成纳米级颗粒。随后，将分散良好的FeP和APP的纳米杂化物（FeP / APP）与亲水性PEI混合，通过冷冻干燥法制备一种复合泡沫。对于FeP / APP，过渡金属铁表现出优异的催化碳化性能。同时，APP还可以催化聚合物的降解以形成保护性炭层。热重分析结合傅立叶变换红外分析（TG-FTIR）测试表明，PEI基泡沫塑料阻燃性的提高归因于F​​eP和APP在冷凝相中的协同作用。含有30 wt％FeP / APP的复合泡沫材料可自行熄灭，在UL-94测试中达到V-1等级。当FeP / APP的含量达到45％时，复合泡沫可以提高到V-0等级，与之相比，放热率和总放热的峰值分别降低了71.8％和74.2％。干净的PEI泡沫。值得注意的是，我们的工作为制备稳定的水性阻燃剂提供了一种有希望的方法，并有望提高水性泡沫，涂料，棉纺织品和其他易燃材料的防火性。