Abstract:Flame retardant finishing of textiles is one of the hottest topics in recent years. In this study, flame-retardant phosphoester polysiloxane (PPSO) was synthesized by N-β-aminoethyl-γ-aminopropyl polydimethylsiloxane (ASO-1), epoxy chloropropane and tributyl phosphate. The chemical structure of PPSO and the intermediates were characterized by infrared spectrum (IR) and proton nuclear magnetic resonance (1H-NMR). Then PPSO was emulsified to obtain transparent emulsion. It was found that the average diameter and the Zeta potential of the emulsion is 62.5nm and +53.71mV respectively by the Malven nanometer particle-size and the Zeta potential analyzer. The emulsion was applied to cotton fabric and the fishing effects of flame retardant agents usage was investigated. Research shows that finished cotton fabric had flammability. The Optimum dosage of the flame retardant was 200g•L-1. By using Thermogravimetry Analysis (TGA), the pyrolysis process of cotton fabrics was studied to explain the flame retardant mechanism of cotton fabrics. The results showed that flame retardant caused fibers to dehydrate and carbonize, increasing the char yield.