Preparation and flame retardant properties of cotton fabrics treated with resorcinol bis(diphenyl phosphate)

A flame-retardant agent, resorcinol bis(diphenyl phosphate) (RDP), was synthesized with resorcinol, phenol and phosphorus oxychloride under a catalytic action of magnesium chloride. Synthesized RDP was applied to cotton fabrics with a bridging agent of urea-formalin resin (UFR) to endow them with flame retardancy. The vertical flammability tests were performed, revealing that cotton fabrics treated with 25% RDP and 15% UFR could exhibit the most reasonable flame retardancy. Here, other properties of cotton fabrics, such as mass increment, color change, resistance to washing and hand feeling, were found to be almost unspoiled. The suitable heat-treating condition for temperature and duration was determined to be 160 °C and 2 min. The results of scanning electron micrography, energy dispersive X-ray and Fourier transform infrared spectroscopy showed that RDP was strongly bonded to cotton fiber with a successful bridging action of UFR. Thermogravimetric analysis confirmed that the coated cotton fabrics possessed flame retardant properties. Graphic abstract