Imparting superhydrophobicity and flame retardancy simultaneously on cotton fabrics

Abstract An eco-friendly hydrophobic flame retardant, ammonium salt of octadecyl phosphate (AMOP) was synthesized and its structure was verified by 1 HNMR, 13 CNMR and 31 PNMR. AMOP imparted flame retardancy and superhydrophobicity to cotton fabrics simultaneously. The water contact angles and limiting oxygen index values of treated cotton reached 161.8° and 27%, respectively. After 30 laundering cycles, the hydrophobicity sustained very well. Thermogravimetric analysis and thermogravimetric-infrared spectroscopy suggested AMOP changed the thermal decomposition path of cotton fibers and the treated sample released less flammable gas during the thermal decomposition process. Cone calorimetry results showed the total heat release and the heat release rate of treated cottons were much lower than those of control cottons. Fourier-transform infrared spectroscopy, energy dispersive X-ray analysis and X-ray photoelectron spectroscopy suggested the AMOP successfully grafted on cotton fabrics through P-O-C groups. Scanning electron micrography showed AMOP caused a rough surface. Graphic abstract