Amine Salt Thickening of Intumescent Multilayer Flame Retardant Treatment

Layer-by-layer assembly often requires numerous deposition steps to obtain a suitable thickness for an effective flame retardant nanocoating. In an effort to make this technique more industrially feasible, an amine salt is added to the rinsing steps of a chitosan/sodium hexametaphosphate (CH/PSP) multilayered system to help facilitate thicker growing films with self-extinguishing capability and fewer processing steps. Cotton fabric coated with CH/PSP is rinsed in water baths containing tris(hydroxymethyl)aminomethane [THAM] and compared to control samples rinsed with deionized water. Only 10 bilayers of the CH/PSP system rinsed with THAM are required to achieve self-extinguishing behavior and pass a vertical flame test, while 15 bilayers of the control system are needed to achieve similar results.