A facile and effective flame-retardant coating for cotton fabric with α-aminodiphosphonate siloxane

To investigate the flame retardancy of α-aminophosphonates on cotton fabrics, a reactive α-aminodiphosphonate siloxane (TTPBD) was successfully synthesized and flame-retardant cotton fabric was prepared by sol-gel coating technology. The chemical structure of TTPBD was confirmed by FT-IR and NMR. The presence of TTPBD coating on the cotton fibers was proved by FT-IR, XPS, and SEM-EDX. The cotton fabrics with TTPBD coating showed good flame retardancy with self-extinguishing behavior. The flame-retardant mechanism was investigated by SEM-EDX, TG, thermogravimetric analysis coupling with Fourier transform infrared spectroscopy (TG-IR) and cone calorimetry test. The results indicated that TTPBD coating owned gaseous and condensed phase flame-retardant mechanism by greatly enhancing thermal stability, improving char-forming ability, decreasing heat and flammable gas release, and increasing inflammable gas release. Also, the preparation process had little effect on the tensile strength and breaking elongation of cotton fabrics, although the whiteness and bending properties had a slight decrease. The coated cotton fabrics remained good char-forming capability after different washing cycles.