A novel flame-retardant system toward polyester fabrics: flame retardant, anti-dripping and smoke suppression

A novel phosphorus-nitrogen-silicon-calcium alginate flame-retardant system was successfully prepared, and it was employed on the surface of polyester fabrics by the surface coating method. The scanning electron microscopy (SEM) and energy dispersive X-ray spectrometer (EDX) were applied to analyze and determine the surface morphology and elemental composition of uncoated and coated polyester fabrics. Obviously, it was observed that the flame-retardant system was coated on the surface of polyester fabrics, and the processed sample generated a dense intumescent char layer after burning. The flame retardancy of uncoated and coated polyester fabrics was characterized by the vertical flammability test (VFT) and limiting oxygen index (LOI) test. Compared with the original fabrics, the optimal coated polyester fabrics were not accompanied by a melt-dripping phenomenon during the combustion process, their LOI value increased from 19.2 ± 0.2% to 32.5 ± 0.3%, and the damage length was also reduced to 6.5 ± 0.2 cm. Simultaneously, thermogravimetric analysis (TGA) and cone calorimetry test (CCT) confirmed that the flame-retardant system changed the thermal degradation process of polyester fabrics and showed a good smoke suppression efficacy. Furthermore, the flame-retardant mechanism of optimal coated polyester fabrics in the gas phase and the condensed phase was effectively proved by the FTIR of char residue and TG-FTIR analysis.