Screening Approaches for Gas-Phase Activity of Flame Retardants

Abstract

Molecular beam mass spectrometry (MBMS) and optical diagnostic techniques, two common combustion science diagnostic tools for studying the impact of material on flames, are evaluated as tools for estimating the gas-phase potential of polymer-flame retardant additives. The gas-phase activity of hexabromocyclododecane (HBCD), a widely used commercial flame retardant, was studied and compared via the two combustion diagnostic techniques. MBMS data for HBCD were reviewed and provided identification of gas-phase active species as well as quantitative information on the degree of effectiveness based upon reduction of OH in a premixed CH4/air/N2 flame. In contrast, optical chemiluminescence detection of OH_ and CH_ provided a simpler technique for monitoring the gas-phase potential of flame retardants. Studies of CH_ and OH_ levels after addition of pyrolyzed products from polystyrene/HBCD blends into a diffusion flame system are compared with MBMS experiments of flames doped with pure HBCD. Comparison of chemiluminescence data with similar data from a small-scale heat release test, the pyrolysis combustion flow calorimeter, indicated that CH_ and OH_ activity relate to the heat release rate for flaming combustion