A novel high whiteness flame retardant for cotton

Abstract

A novel self-buffering flame retardant ammonium amino trimethylene phosphate (AATMP) was synthesized by a facile one-step water-solvent method to solve the problem of flammable cotton triggering easily and spreading fire. The structure of AATMP FR was verified by FT˗ IR, 1H NMR, 13C NMR, and 31P NMR spectra. AATMP was grafted onto cotton fabrics using the dip-dry-cure method, and the grafted cotton was confirmed by FT-IR spectra. The limiting oxygen index (LOI) of cotton treated with a mass concentration of 15% AATMP solution reached 43.9%. After 30 and 50 laundering cycles, LOI values were maintained at 34.8% and 29.7%, respectively, suggesting that AATMP can be used as a durable flame retardant. The vertical flammability of treated cotton indicated no afterflame or afterglow time for comparison. Cone calorimetry results revealed that the total heat release of treated cotton was 1.6 MJ/m2, lower than that of control cotton (2.8 MJ/m2). The peak heat release rate of control cotton was 195.1 kW/m2, much higher than that of treated cotton (16.1 kW/m2, further confirming the efficient fire resistance of AATMP. Thermogravimetry analysis and thermogravimetric-infrared spectroscopy indicated that AATMP FR altered the thermal decomposition pathway of treated cotton. X-ray diffraction patterns and scanning electron microscopy suggested that the structure of treated fibers was hardly affected. The tensile strength and whiteness of treated cotton fabrics were sustained well due to the self-buffering property of the neutral AATMP molecule.