Developing Lyocell Fabric With Flame‐Retardant and Hydrophobic Properties an Using N‐P‐Si Synergistic System

ABSTRACT To address the high flammability of Lyocell fabric, a green Lyocell fabric featuring nitrogen‐phosphorus‐silicon synergistic flame retardancy was developed in this study. SiO 2 nanoparticles were deposited onto the fiber surface, where phytic acid (PA) and nicotinamide (NA) were further anchored via covalent grafting. The results show that compared with pure Lyocell fabric, the peak heat release rate (pHRR) of a new flame‐retardant fabric, designated PANA41‐Si and prepared using PA, NA, and nano‐silica, was reduced by 34.3%. The limiting oxygen index (LOI) value of the PANA41‐Si fabric was measured to be 36.2%. The flame‐retardant performance of PANA41‐Si is ascribed to the formation of a dense carbon layer catalyzed by phosphoric acid and to cross‐linking by NA. The thermal decomposition of NA releases non‐flammable gases, and the free radical scavenging effect derived from phosphorus‐containing free radicals also effectively inhibits flame spread. Moreover, a water contact angle (WCA) of 136° was achieved for PANA41‐Si, in contrast to that of the pure Lyocell fabric (0°). The treated fabric also retained acceptable whiteness and mechanical properties. This work provides a strategy that synergistically combines biomass‐based flame retardants and inorganic nanoparticles to impart flame retardancy to Lyocell fabric, which will expand its application scope.