Synthesis and performance study of sulfur-containing amino acid ammonium phosphate type flame retardants for cotton fabric

In order to obtain cotton fabrics with high efficiency flame retardance, a new ammonium phosphate type active flame retardant N, N -bis (ammonium phosphate) cysteine (NP-BG), which is nonleaching, covalent attached, durable, functional flame retardants, was synthesized by Mannich reaction and applied to the flame-retardant modification of cotton fabrics. Test results such as FTIR and XPS showed that cotton fabrics had been successfully grafted with NP-BG. The LOI of cotton fabrics treated with 30 % flame retardant was as high as 40.2 %, and after 50 washes, the LOI of cotton fabric was still as high as 28.8 %; demonstrating the durability of flame retardance. The thermogravimetric-infrared coupling (TG-FTIR) test results showed that the flame retardant could change the thermal decomposition pathway of cotton fabric and produce a large amount of residual carbon, thus reducing the decomposition of cotton fiber and the release of flammable gas. In addition, cone calorimetry (CONE) experiments showed that the total heat release (THR) and heat release rate (HRR) of cotton fabrics were significantly reduced after the flame-retardant treatment. These findings indicate that NP-BG is a new flame-retardant material with good application prospects.