Highly Flame Retardancy of Cotton Fabrics with a Novel Phosphorus/Nitrogen/Silicon Flame-Retardant Treating System

A novel reactive flame retardant (FR) containing phosphorus, nitrogen, and silicon was synthesized successfully, and its chemical structure was fully characterized by Fourier transform infrared spectrometry and nuclear magnetic resonance spectrometry (H-1-NMR and P-31-NMR). Then it was used to impart flame resistance to cotton fabrics. Vertical flammability and limiting oxygen index test were used to evaluate the flame retardancy of the cotton fabrics treated with FR. When the cotton treated with 150 g/l FR and 50 g/l sodium hypophosphite, the finished cotton can pass the vertical flammability test. Thermogravimetry (TG) was used to evaluate thermal behavior of FR and cotton fabrics. TG results demonstrated that the FR has good thermostability and char-forming ability. After treatment with FR, the thermal stability of the cotton fabrics was clearly improved, indicating that the FR can protect cotton fabric from fire to a certain degree. Furthermore, attenuated total reflection Fourier transform infrared spectroscopy was utilized to characterize the chemical structure of FR treated cotton fabrics. Finally, the surface morphology in different regions of the treated cotton was observed using scanning electron microscopy.