Flame retardancy of epoxy resin doped with pentaerythritol diphosphonate melamine-urea-formaldehyde resin salt

Pentaerythritol diphosphonate melamine-urea-formaldehyde resin salt, a novel cheap macromolecular intumescent flame retardants (IFR), was synthesized, and its structure was a caged bicyclic macromolecule containing phosphorus characterized by FT-IR, which was applied to epoxy resin (EP). The thermal behavior and flame retardancy of samples were determined by TG-DTG and cone calorimeter (CONE). Activation energy for the decomposition of samples was obtained using the Broido equation. The resultant data show that for the flame retardant doped EP, average value of heat release rate is decreased by 30.7%, total heat release decreased by 52.2%, smoke and gas release decreased by 42.7%, CO release decreased by 70.5%, CO2 release decreased by 76.5%, and char yield is increased by 19.1%. 30% weight of IFR is doped into EP to get 30.5 of the limiting oxygen index, whose flame retardancy is similar to DOPO. The activation energy for the decomposition of EP is 76.5 kJ/mol while it becomes 86.5 kJ/mol when IFR is doped into, decreased by 10 kJ/mol, which shows that IFR can catalyze decomposition and carbonization of EP.