Terminating heat and mass transfer: Graphite-tailings gelatum coating for polyurethane foam with super flame retardancy and smoke suppression

Endowing polyurethane foam with high fire resistance and smoke suppression is a persistent challenge in the combustion industry. This study introduces a graphite-tailings and calcium-alginate (GT@CA) gelatum coating that terminates the heat and mass transfer process in a flexible polyurethane foam (PUF) matrix with fire resistance and smoke suppression. The PUF/GT@CA-3 composite exhibits high flame retardancy with a V-0 rating in the vertical combustion test. Furthermore, GT@CA forms protective and char layers that terminate the heat and mass transfer during thermal degradation, the thermal stability and fire behavior of the PUF/GT@CA composites are markedly optimized. Meanwhile, the smoke production rate and total smoke production of PUF/GT@CA-3 composite are dramatically reduced to 1.17 x 10-2 m2/s and 2.73 x 10-1 m2, respectively (81.19% and 83.26% lower than those of pure PUF, respectively). Finally, the flame retardant and smoke suppression mechanism of GT@CA in PUF is deduced. The GT@CA competently promotes the char forming process of the PUF matrix while fabricating an impervious protective layer. The char and protective layers on the PUF surface restrain oxygen diffusion, heat diffusion, and micromolecule volatilization processes. Hence, GT@CA is expected to expand the application range of PUF matrixes in the advanced materials field. Schematic showing the fabrication of graphite-tailings and calcium alginate (GT@CA) coatings on polyurethane foam (PUF) and the proposed flame-retardant and smoke-suppression mechanism of GT@CA on the PUF matrix. image