Layered metal phenyl phosphinates (PP) with nickel, cobalt, copper and iron were produced by precipitation in aqueous solution. 2% loading of these compounds were 2D-layered into polystyrene by melt mixing. Copper-PP achieved the greatest reduction in PHR (-35%).
Gramm-Schmidt absorbance curves show that the layered metal PPs reduce emissions of volatile organic compounds (VOCs) in smoke, again with copper-PP being the most effective in reducing VOCs emissions. The authors suggest this smoke toxicity reduction effect results both from char residues blocking release and from a catalytic effect leading to carbonisation of VOCs.
“Two-dimensional metal phenylphosphonates as novel flame retardants for polystyrene”, J. Wang et al., Ind. Eng. Chem. Res. (I&EC), 2017, 56 (25), pp 7192–7206 http://dx.doi.org/10.1021/acs.iecr.7b00858