Characterisation of soot particulates from fire retarded and nanocomposite materials, and their toxicological impact

Polyamide 6 (PA 6) and polypropylene (PP) containing fire retardants, nanofillers or a combination of both additives have been investigated using the steady state tube furnace (ISO TS 19700). The samples were tested under three different fire conditions, to determine the effect of additives on the soot production or toxic product yields. The particle size distribution of the soot was investigated with a cascade impactor, and the separated soot fractions examined by SEM. The predicted deposition based on aerodynamic size of particulates in the human respiratory tract shows clear differences between the pure polymer and its additive counterparts. In all ventilation conditions the virgin polymer produces the least amount of soot, both the additives used (fire retardant and nanoclay) increase the amount of soot, mainly within 0.5-1.0 μm range, for each fire condition. A large contribution to the total soot mass originated particles smaller than 0.5 μm.