Surface modification of fabrics for improved flash-fire resistance using atmospheric pressure plasma in the presence of a functionalized clay and polysiloxane

Improving flash-fire resistance of otherwise flame resistant fabrics is a recognized challenge within the civil emergency and defence communities. Simulation of the flash-fire condition using cone calorimetry has demonstrated the effectiveness of atmospheric plasma treatments in which either a functionalized clay, a polysiloxane (poly(hexamethyldisiloxane)) or both are deposited on to plasma-activated fiber surfaces. Textile substrates comprised flame retardant (Proban (R)) cotton and a poly (meta-aramid) (Nomex (R)). Results show that the generated surface layer has a measurable effect on fabric ignition and burning characteristics when exposed in a cone calorimeter at heat flux levels up to 70 kW/m(2). Reductions in peak heat release rates (PHRR) are observed for all substrates especially for argon/clay and argon/clay/polysiloxane, plasma-treated samples, with reductions of over 50% being observed for Proban (R) cotton and smaller reductions (<= 20%) for Nomex (R) fabrics. Gravimetric, scanning electron microscopic, and cone calorimetric studies show that both original surface deposits and subsequent properties are retained after a simulated washing process including the argon/clay plasma-treated Proban (R) and Nomex (R) fabrics in which no potentially binding polysiloxane was present. This suggests that plasma-activated fiber surfaces in the presence of a functionalized clay enable relatively strong binding forces to be generated. The results provide further evidence in addition to our earlier reported studies that atmospheric plasma treatment of fabric surfaces in the presence of a functionalized clay produces an inorganic coating that confers reduced flammability at the high heat fluxes used suggesting increased resistance to flash-fire ignition. Copyright (C) 2010 John Wiley & Sons, Ltd.