A novel phosphorus-containing compound (DOPO-THPO) is synthesized via the Atherton-Todd-reaction between 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and trihydroxymethylphosphine oxide (THPO), and then employed as flame retardant for diglycidyl ether of bisphenol A/4-4 diaminodiphenylmethane epoxy resin (DGEBA/DDM). Based on the ultra-low phosphorus loading, the highly efficient flame retarded epoxy resin (EP) systems are successfully established in this work. Remarkable improvements in the limited oxygen index (LOI) values and UL-94 rating of flame retarded EP systems are observed. In detail, when the phosphorus content is only 0.33 wt%, the EP composite receives V-0 rating in the UL-94 vertical burning test with LOI value of 30%. Heat release of EP composites is obviously inhibited with the formation of intumescent char residue. Furthermore, TG-IR result of DOPO-THPO shows the generation of phosphorus containing products, which may provide a gaseous phase flame retardant function on EP. This work may open the new door for the construction of highly efficient flame retardant EP system based on the ultra-low phosphorus loading.

通过9,10-二氢-9-氧杂-10-磷酸菲菲（DOPO）和三羟甲基氧化膦（THPO）之间的Atherton-Todd反应合成了一种新型的含磷化合物（DOPO-THPO），然后用作双酚A / 4-4二氨基二苯基甲烷环氧树脂（DGEBA / DDM）的二缩水甘油醚的阻燃剂。基于超低的磷负载量，在这项工作中成功建立了高效阻燃环氧树脂（EP）系统。观察到阻燃EP系统的极限氧指数（LOI）值和UL-94等级显着提高。详细地说，当磷含量仅为0.33 wt％时，EP复合材料在UL-94垂直燃烧试验中的LOI值为30％，获得V-0等级。膨胀型炭渣的形成明显抑制了EP复合材料的热释放。此外，DOPO-THPO的TG-IR结果表明生成了含磷产物，可在EP上提供气相阻燃功能。这项工作可能会为基于超低磷含量的高效阻燃EP系统的建设打开新的大门。