Suppression Effect of MoS2 Nanosheets for CO and CO2 Production During Combustion of Flexible Polyurethane Foams

In this work, a facile flame-retardant nanocoating was developed to reduce the fire hazard of flexible polyurethane (FPU) foam. MoS2 nanosheets was prepared using an ultrasonic-assisted liquid-phase exfoliation method. Subsequently, FPU foam was deposited with a three-layered coating composed of the positively charged guargum and negatively charged MoS2/sodium alginate by a layer-by-layer method. TEM analysis indicated the successful preparation of MoS2 nanosheets, and SEM images showed that MoS2 nanocoating was covered well on the surface of FPU foams. The cone calorimeter results indicated that the MoS2 coated FPU foam showed a remarkable increase in the char residues yield (from 3.6 to 11.9 wt%), great reduction in total CO production (from 0.54 to 0.30 g) and total CO2 production (from 22.08 to 15.13 g), respectively, as compared with those of the pure FPU foam. Char residue analysis showed that MoS2 nanosheets promoted the formation of compact char residue layer. Such a significant reduction in the CO and CO2 production for FPU foams could be attributed to the surface adsorption, physical barrier and catalytic carbonization effects of MoS2 nanosheets.