Fire Retardation in Nylon 6-Layered Silicate Nanocomposites: Films, Fibers and Fabrics

摘要

By “flame retardancy” we mean any modification that would reduce the materials propensity to burn or decrease the rate of burning / rate of heat release or produce less smoke and toxic combustion products or a combination of these properties. Many flame retardant approaches that produce the above changes have been developed and are in use today [1,2]. However, most of these approaches involve addition of about 30-60 wt% of flame retardant fillers which is too high filler level for fiber formation and their applications and in case of textile materials with topical finishing of such a higher dose of fillers adversely affect the fabric properties like drape and hand. Also some of the flame retardant additives release toxic products during combustion and hence, unacceptable on environmental aspects[3]. Hence, there is a need to find a better flame retardant additive for fibers, fabrics and related textile materials. Fibers are “thermally thin” in their behavior, i.e. easy to heat up to ignition. The surface of the fibers will be fuel rich and their high surface area could lead to enhanced oxygen contact and turbulent combustion. The effect of oxygen on the decomposition of the fibers will be secondary to the thermal effect of the “thin” cross section of the fibers relative to decomposition. On the other hand when a fabric is exposed to radiant heat the fiber surface first reach the melting temperature and on further heating reach the ignition temperature upon which they start to burn. The flame retardant effect of montmorillonite platelets on nanocomposite fabrics would depend on how intact the material remains during burning and how well the barrier property is maximized. This in turn would strongly depend on fabric geometry and test conditions and is difficult to predict based on flammability studies of nanocomposites