Novel FlameRetardants Containing 9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxideand Unsaturated Bonds: Synthesis, Characterization, and Applicationin the Flame Retardancy of Epoxy Acrylates.

A novelflame retardant containing 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide(DOPO) and unsaturated bonds (DOPO-HEA) was synthesized and incorporatedinto epoxy acrylates (EA) in different ratios. The effects of DOPO-HEAon the thermal stability, flame retardant properties, and degradationmechanisms of EA were investigated. The flame retardant propertiesof the resins showed that the incorporation of DOPO-HEA into EA couldimprove the limiting oxygen index (LOI) values and greatly reducethe peak heat release rate (pHRR) of EA. The thermal properties ofthe resins indicated that the incorporation of DOPO-HEA into EA coulddistinctly improve the char residues. Moreover, the thermal degradationprocesses of the EA/DOPO-HEA resins were investigated by direct pyrolysis/massspectrometry (DP–MS). As for the variation in the condensedphase, FTIR and Raman spectroscopies were adopted to investigate thechar residues. Due to the catalyzing charring effect and the gas flameretardant effect of phosphorus, the resins exhibited significant improvementsin flame retardant properties. [ABSTRACT FROM AUTHOR]