Effect of layer-by-layer self-assembled sepiolite-based nanocoating on flame retardant and smoke suppressant properties of flexible polyurethane foam

In this study, a facile and water-based route was developed for fabricating flame retardant and smoke suppressant flexible polyurethane foam (FPUF). FPUF was deposited with a multilayered coating by layer-by-layer (LbL) self-assembled method, which was composed of the positively charged polyethyleneimine (PEI) and negatively charged alginate and sepiolite. The prepared coatings were shown to be successfully constructed on the surface of FPUF, as characterized by scanning electron microscopy and energy dispersive X-ray spectroscopy. Subsequently, the combustion behavior of FPUF was evaluated by cone calorimeter. Results showed that, with 6 bilayers PEI/sepiolite + alginate coating, the peak heat release rate and total heat release of PU-6 were reduced 76% and 27%, respectively, as compared with those of untreated sample. Meanwhile, the deposited coating could effectively reduce the smoke production of FPUF, as evidenced by the remarkable reduction of smoke production rate and total smoke production for the treated FPUF.