Two novel N‐phosphorylated iminophosphoranes based on 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) were evaluated as flame retardant (FR) additives. They were incorporated in two different epoxy resin systems (EP) based on diglycidyl ether of bisphenol A (DGEBA) and a novolac glycidyl ether (DEN438) both cured with dicyandiamide/fenuron (D/F). Decomposition temperatures and char yields of the cured EP were evaluated and compared to the corresponding neat EP as well as to structurally related compounds. The flame‐retardant properties were investigated using the UL‐94 V test and further verified with cone calorimetry. The N‐phosphorylated iminophosphoranes with DOPO moieties exhibit distinctive flame‐retardant effects in DGEBA/D/F and DEN438/D/F, depending on the chemical environment around the second phosphorus atom, even with low FR content. If the iminophosphorane is triphenyl phosphite based the mode of action is assigned to act mainly in the condensed phase hence being advantageous in DGEBA/D/F compared to the triphenylphosphine‐based iminophosphorane, which in turn is more active in the gas phase resulting in superiority in DEN438/D/F.

中文翻译：

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基于9,10-二氢-9-氧杂-10-磷苯并菲-10氧化物的N-磷酸化氨基正膦酸酯及其在环氧树脂中的阻燃性能

两种基于9,10-二氢-9-氧杂-10-磷菲10-氧化物（DOPO）的新型N-磷酸化亚氨基正膦被评估为阻燃（FR）添加剂。它们被掺入两种基于双酚A的二缩水甘油醚（DGEBA）和线型酚醛清漆的缩水甘油醚（DEN438）的环氧树脂体系中，两者均用双氰胺/苯磺隆（D / F）固化。评价了固化EP的分解温度和炭产率，并将其与相应的纯EP以及与结构相关的化合物进行比较。使用UL-94 V测试对阻燃性能进行了测试，并通过锥形量热法进行了进一步验证。根据第二个磷原子周围的化学环境，具有DOPO部分的N-磷酸化亚氨基正膦在DGEBA / D / F和DEN438 / D / F中表现出独特的阻燃效果，即使FR含量低。如果亚氨基膦烷是基于亚磷酸三苯酯的，则将作用方式指定为主要在缩合相中起作用，因此，与基于三苯膦基的亚氨基膦烷相比，DGEBA / D / F具有优势，后者在气相中的活性更高，因此具有优越性在DEN438 / D / F。