A novel composite coating containing P/N/B and bio-based compounds for flame retardant modification of polyester/cotton blend fabrics

Herein, a novel composite coating containing P/N/B and bio-based compounds was developed and applied to the flame-retardant finishing of polyester/cotton (T/C) blend fabrics. The flame-retardant coating was prepared with a combination of triethanolamine borate, diethylenetriamine pentamethylene phosphonic acid and calcium alginate. The combined characterization of scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS) proved that the coating system has been successfully processed to the surface of T/C blend fabrics. The results of limiting oxygen index (LOI), horizontal flammability test (HFT) and vertical flammability test (VFT) showed that the P/N/B/Ca-T/C blend fabrics obtained good flame retardancy and exhibited excellent char-forming ability. Meanwhile, the thermal stability and combustion behavior of the blend fabrics before and after coating were evaluated by thermogravimetric (TG) and cone calorimetry tests. Obviously, the flame-retardant coating transformed the thermal degradation process of T/C blend fabrics and suppressed their heat and smoke release during combustion. Furthermore, Fourier transform infrared (FTIR) spectroscopy of char layers and thermogravimetric-Fourier transform infrared spectroscopy (TG-IR) analysis indicated that the composite coating exerted flame retardancy to T/C blend fabrics in both the condensed and gas phases.