Fundamental flame spread and toxicity evaluation of fire retarded polymers

A simple method is developed for characterizing the fire performance and toxicity of polymers using basically three but up to five parameters if necessary. The first parameter is related to fire spread and growth (corresponding to UL-94 and the FIGRA of SBI), the second parameter is the smoke yield (corresponding to the SMOGRA of SBI), the third parameter is the inefficiency of combustion (related to unburned hydrocarbon compounds and their toxicity as verified by tube furnace measurements), the fourth parameter is the mass of residue remaining and the fifth parameter is a heat release parameter for thermally thin conditions (the maximum mass loss rate in TGA multiplied by the effective heat of combustion deduced from the Cone Calorimeter tests). The developed methodology was used to compare brominated and halogen free fire retardants in formulations of PBT, PA66, PPE/HIPS and PC/ABS. It is confirmed that the studied environmentally friendly alternatives to brominated fire retardants offer comparable fire performance with lower toxicity.