Properties of epoxy resin composites containing 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide

Abstract

Flame-retardant epoxy resin composites were prepared via in situ polymerization of diglycidyl ether of bisphenol A epoxy monomer and 4,4'-diaminodiphenyl methane, using 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide as additives. The thermal and flame-retardant properties of cured samples were investigated by differential scanning calorimetry, thermogravimetric analysis, limiting oxygen index (LOI), UL-94 vertical burning test, and cone calorimetry. Evaluation of thermal properties demonstrated that the resulting composites achieved high thermal stability with high char yields. Results indicated that the increase in LOI and UL-94 rating was not obvious. The peak of heat release rate of epoxy resin composite containing 15wt.% DOPO was 57.6% less than that of neat epoxy resin. Meanwhile, other flame-retardant parameters were also improved. Scanning electron microscopy was used to study flame retardancy mechanism.