Organo-metal PIN flame retardant improved fire performance and reduced peak smoke emission by nearly 20%. The well-recognised phosphorus PIN FR, DOPO, was reacted with an amine compound, a sodium amino sulphate and optionally also copper sulphate, resulting in a phosphorus – nitrogen – sulphur – sodium or copper organometallic PIN FR molecules DCSA-Na and DCSA-Cu. This was cured into epoxy resin at 0 – 7% loading. At 5% loading of DCSA-Cu, peak heat release was reduced by 30%, peak smoke release rate by nearly 20%, UL 94 V-0 was achieved (neat epoxy was NR) and physical characteristics of the epoxy were not significantly modified. Fire performance is considered to result from char generation by phosphorus, cross-linking of the epoxy and reduced smoke toxicity from copper catalysis of conversion of CO to CO2.
“An Organometallic Flame Retardant Containing P/N/S−Cu2+ for Epoxy Resins with Reduced Fire Hazard and Smoke Toxicity”, J. Li et al., ACS Omega 2023, 8, 16080−16093 https://doi.org/10.1021/acsomega.2c08226