A P/N flame retardant for polyester-cotton fabrics: Flame retardancy, mechanical properties and antibacterial property.

A phosphorus‑nitrogen synergistic flame retardant (named POI) was obtained by the chemical reaction between phenylphosphonic acid (PPOA) and polyethyleneimine (PEI), and used to give the flame retardancy of PTCO. The effects of PPOA and POI on various properties of PTCO were investigated. PPOA obviously improved the flame retardancy of PTCO/PPOA, while the breaking force of PTCO/PPOA was greatly reduced. However, the introduction of PEI made the surface of fabrics smoother. PTCO/POI had better flame retardancy than PTCO/PPOA did, and the limiting oxygen index value of PTCO/POI reached to 29.8 %. POI had a good effect on reducing the Rmax of both cotton and polyester components. The phosphoric acid groups in POI can promote the dehydration and carbonization reactions of PTCO, which protects the inner fabrics, and POI can release incombustible gases such as NH3 and N2 during burning, which can dilute the oxygen concentration. The flame-retardant mechanism of PTCO/POI was mainly the condensed phase. At the same time, there were no changes in whiteness and mechanical properties compared with those of PTCO, and it also had antibacterial property. This work provides a simple and effective method to prepare flame-retardant and antibacterial PTCO.