For structural composites used in vehicles and aircraft, flame retardant chemistries which enhance char formation and reduce heat release are preferred. Phosphorus-based and phosphorus–nitrogen flame retardants for epoxies have been well studied to date, but phosphorus hydrazides have not been studied for their flame-retardant potential in epoxy. These hydrazides offer some novel structures and they can potentially offer a combination of vapor and condensed phase flame retardant action. A series of eight compounds were systematically investigated in this study as reactive flame retardants in a bisphenol F epoxy/aliphatic amine resin system at a level of 2.5 wt% phosphorus. Results suggest that the phosphorus hydrazides react with the epoxy during thermal decomposition, and they also release nitrogen during flaming combustion of the epoxy matrix. The observed reactions resulted in increased char yields and reduced total heat release, while simultaneously lowering heat of combustion and total smoke release.

中文翻译：

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有机磷酰肼作为环氧树脂的潜在反应性阻燃剂

对于用于车辆和飞机的结构复合材料，优选能促进炭形成和减少热释放的阻燃化学品。迄今为止，用于环氧树脂的磷基和磷-氮阻燃剂已得到充分研究，但尚未研究磷酰肼在环氧树脂中的阻燃潜力。这些酰肼提供了一些新颖的结构，它们可以潜在地提供蒸汽和凝聚相阻燃作用的组合。本研究系统地研究了一系列八种化合物作为双酚 F 环氧/脂肪胺树脂体系中的反应性阻燃剂，磷含量为 2.5%。结果表明，磷酰肼在热分解过程中会与环氧树脂发生反应，并且在环氧树脂基质的火焰燃烧过程中也会释放出氮气。