Synthesis of a Bio-Based Intumescent Flame Retardant Without Halogen and Its Application on Cotton Fabric

A novel halogen-free, formaldehyde-free, intumescent flame retardant, ammonium salt of erythritol phosphoric ester acid (AEPEA), was synthesized and coated onto cotton fabrics to increase the flame retardancy of cotton fabrics. Fourier-transform infrared, scanning electron microscopy, and X-ray diffraction were used to analyze cotton samples. The limiting oxygen index (LOI) of cotton treated with 300 g/L AEPEA reached 40.1% and the carbon length was 4.2 cm. After 50 laundering cycles, the LOI value could still reach 27.8%. Thermo-gravimetry and the cone calorimetry test were used to further investigate the flame retardancy and thermal stability of the treated cotton fabrics, and the results proved that the thermal stability of treated cotton was greatly improved. X-ray photoelectric spectrometry was used to analyze the carbon residue of flame-retardant cotton samples. In addition, the mechanical properties of the treated cotton only decreased slightly.