Flame resistance in foam and fabric using antiflammable nanocomposite coating
Thin films were deposited on polyurethane (PU) foam and cotton fabric using layer-by-layer (LbL) assembly. Branched polyethylenimine (BPEI) and montmorillonite (MMT) were used as polycation and polyanion, respectively. Two coatings were created with solutions of BPEI (pH 8 or 10) and MMT (0.2 wt. %). The thickness and composition of the coatings were studied by ellipsometry and quartz crystal microbalance. On PU foams, 40 bilayers (BL) of coating using BPEI at pH 8 give higher char percentage (11.7 %) than pH 10, when heated at 400C under an air atmosphere in thermogravimetric analysis. The same coating was applied onto cotton fabrics but at different bilayer numbers (10, 20, and 30 BL), leaving similar amounts of char in vertical flame testing. Thermogravimetric analysis showed that coated fabrics left 7.3 % char after heating at 500 C, over an order of magnitude more char than from uncoated fabric. Bare and coated polyurethane foams were subjected to oven-heating treatment. The thermal stability of fabrics and foams was observed by scanning electron microscopy imaging.