The influence of an N-alkoxy HALS on the decomposition of a brominated fire retardant in polypropylene

This work studies the effect of an N-alkoxy HALS on the thermal decomposition of a brominated phosphate ester fire retardant. We have monitored the fate of the fire retardant in the presence of the N-alkoxy HALS during thermal decomposition using TGA, FTIR, TD-GC-MS, NMR and ESR methods. We have shown that the two additives interact in the condensed phase at temperatures below the onset of polymer decomposition to produce 1,3-dibromo-2,2-bis(bromomethyl)-propane as the main decomposition product. It is believed that this molecule is the key to the fire retardant action of the brominated phosphate ester because it readily decomposes to the effective gas phase flame inhibiting agent, HBr.