Synergistic UV-curable flame-retardant finish of cotton using comonomers of vinylphosphonic acid and acrylamide

Abstract

While ‘Pyrovatex’ and’ Proban’ processes have been widely used for durable flame-retardant finishing of cotton, the flame retardants could release formaldehyde inevitably during or even after the finishing process, which is not environmentally compatible. As a new formaldehyde-free flame retardant and finishing process, the comonomers of vinylphosphonic acid (VPA) and acrylamide (AAm) can be in situ copolymerized upon LED-UV irradiation and impart excellent flame retardancy to the cotton. The increasing AAm addition enhanced fixation, flame retardancy effectivity and synergistic effectiveness by reducing the steric hindrance between the VPA monomers during the copolymerization. Also the multifunctional crosslinkers of either methylene bisacrylamide or triacryloylhexahydro triazine significantly improved the laundering durability of the finished fabrics. The increased char formation and residue number after pyrolysis indicated the solid-phase retarding mechanism of the synergistic VPA and AAm combination.