Suppression Effect of MoS 2 Nanosheets for CO and CO 2 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. MoS 2 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 MoS 2 nanosheets, and SEM images showed that MoS 2 nanocoating was covered well on the surface of FPU foams. The cone calorimeter results indicated that the MoS 2 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 CO 2 production (from 22.08 to 15.13 g), respectively, as compared with those of the pure FPU foam. Char residue analysis showed that MoS 2 nanosheets promoted the formation of compact char residue layer. Such a significant reduction in the CO and CO 2 production for FPU foams could be attributed to the surface adsorption, physical barrier and catalytic carbonization effects of MoS 2 nanosheets.