Effect of a triazine ring-containing charring agent on fire retardancy and thermal degradation of intumescent flame retardant epoxy resins

A triazine ring-containing charring agent (PEPATA) was synthesized via the reaction between 2,6,7-trioxa-l-phosphabicyclo-[2.2.2]octane-4-methanol (PEPA) and cyanuric chloride. It was applied into intumescent flame retardant epoxy resins (IFR-EP) as a charring agent. The effect of PEPATA on fire retardancy and thermal degradation behavior of IFR-EP system was investigated by limited oxygen index (LOI), UL-94 test, microscale combustion calorimetry (MCC), thermogravimetric analysis (TGA) and thermogravimetric analysis/infrared spectrometry (TG-IR). The glass transition temperatures (T(g)) of IFR-EP systems were studied by dynamic mechanical analysis (DMA). The LOI values increased from 21.5 for neat epoxy resins (EPs) to 34.0 for IFR-EP, demonstrating improved flame retardancy. The TGA curves showed that the amount of residue of IFR-EP system was largely increased compared to that of neat EP at 700 degrees C. The new IFR-EP system could apparently reduce the amount of decomposing products at higher temperatures and promotes the formation of carbonaceous charred layers that slowed down the degradation. Copyright (C) 2010 John Wiley & Sons, Ltd.