Flame retardation of polyester/cotton blended fabrics via intumescent sol-gel coatings

Abstract

Sol-gel coatings have long been applied to improve the flame retardancy of fabrics, but they often exhibit unsatisfactory flame-retardant efficiency for polyester/cotton blended fabrics. Therefore, an intumescent coating called DAM was constructed in this work by modifying 3-aminopropyl triethoxysilane with amino phosphonates and melamine through neutralizition reaction of the ingredients. Then, DAM was deposited on the surface of the fabric as a homogeneous coating via sol-gel technique. It was found that DAM accelerated the dehydration of cotton at a relatively low temperature but did not influence the thermal decomposition of polyester. With DAM add-ons of 8% and 15%, the coated fabrics severally named DAM-8 and DAM-15, self-extinguished in horizontal and vertical flame tests, with liming oxygen index values of 23.0% and 26.0%, respectively. In the cone calorimetry test, the ignition of the fabric was slightly delayed owing to the presence of the DAM, while the total heat release and peak heat release rate of the DAM-15 were reduced by 26.1% and 46.3%, respectively. DAM showed flame-retardant activities in both condensed and gaseous phases. Hand assessment of the fabric via the PhabrOmeter system suggested that the presence of the DAM caused the coated fabric to be smoother but a little more rigid than the uncoated fabric.