Epoxy-based multilayers for flame resistant flexible polyurethane foam (FPUF)

Flexible polyurethane foam (FPUF), a widely used cushioning and comfort component for homeware and automobile industries if tailored for flame resistance, can exhibit enhanced market value. With the view to preparing such protective films, multilayered coating composed of montmorillonite (MMT) and triphenyl phosphate (tPP) along with polyethyleneimine (PEI), poly[(o-cresyl glycidyl ether)-co-formaldehyde] (CNER), tPP solution and MMT suspension was deposited via layer-by-layer technique so as to suppress the flammability of FPUF. A comparative study applying cone test revealed that multilayered coatings having PEI(CNER/NH2-MMT/PEI)(n) and PEI(CNER/NH2-MMT/tPP)(n) architectures, where n signifies the number of layer pairs, exhibited remarkable decrease in peak heat release rate (pHRR) of 20 and 25%, respectively, as compared to uncoated FPUF. Moreover, these coatings showed a 50% reduction in fire growth rate index (FIGRA) when compared to uncoated FPUF. This significant decrease in FIGRA after a specific combination of epoxy-clay features that such multilayered coatings can be used to protect the underlying FPUF due to the labyrinth effect offered by MMT and accelerated char formation by tPP. Furthermore, the evolution of volatile gases upon combustion of multilayered coated foam decreased due to the inhibition of oxygen permeation owing to the protective effect of the coating. (c) 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48890.