Phytic acid-based hybrid coating for improving the flame-retardancy of flexible polyurethane foam

The development of environmentally benign flame retardant technology is crucial for flexible polyurethane foam (FPUF). Herein, a hybrid organic-inorganic coating (CNT–NH2–PA) was prepared through a facile salt formation reaction between biomass phytic acid (PA) and aminated carbon nanotubes (CNT-NH2) on FPUF. The obtained flame retardant foam (FPUF@CNT–NH2–PA) passed the UL-94 rate of V-0, with a high limiting oxygen index (LOI) of 27.6 ± 0.3 %. More importantly, the cone calorimeter (CC) results demonstrated that the peak heat release rate (PHRR) of FPUF@CNT–NH2–PA was reduced by 39.7 % compared with that of neat foam. The mechanism analysis confirmed that a dense and compact char layer was formed during the combustion, which can effectively prevent the massive diffusion of heat and oxygen from the FPUF. Besides, the compression tests have clearly shown that the FPUF@CNT–NH2–PA retained the excellent mechanical nature of FPUF. Therefore, this easy and efficient process provided a powerful basis for technology and potential industrial applications.