Ecofriendly Flame-Retardant Cotton Fabrics: Preparation, Flame Retardancy, Thermal Degradation Properties, and Mechanism

Flame-retardant (FR) cotton fabrics were successfully prepared with the reactive product of (3-piperazinylpropyl)methyldimethoxysilane and phytic acid, denoted as GPA, through a quick dip-coating technology. The structure, surface micromorphologies, thermal degradation properties, flame retardancy, and combustion properties of samples were assessed. GPA was successfully deposited on the surface of cotton fabrics, which was proved by the results of Fourier-transform infrared analysis as well as scanning electron microscopy coupled with energy dispersive spectrometry (SEM–EDS). During a vertical burning test, FR cotton-3, with an increased mass of 14.33 wt %, immediately extinguished after removing the igniter, while the control was entirely burned. The deposition of GPA to create flame-retardant cotton fabrics led to the serious decrease of heat release rate and total heat release. The promoted flame retardancy resulted from the formed thermally stable residues on the surface of cotton fabrics, which held back mass/heat transfer. Thermogravimetric analysis coupled with Fourier-transform infrared analysis (TG–FTIR) results indicated that flame-retardant cotton fabrics released more nonflammable gases (H2O and NH3) and less flammable gases than the control. According to the results of TG–FTIR, SEM–EDS, and X-ray photoelectron spectroscopy, the mechanism of the flame retardancy of GPA on the cotton fabrics was proposed.