Abstract: With assistance of bio-based chitosan and anionic alginate,a natural- polysaccharides- derived flame retardant coating was constructed onto the surface of poly (ethylene terephthalate)(PET) fabrics, by electrostatic-guided layer-by- layer assembly. The successful self- assembly deposition of chitosan and sodium alginate was confirmed by scanning electron microscopy.The effect of the dosage of chitosan and sodium alginate on the thermal stability, flame retardancy and smoke suppression of PET fabrics were investigated by thermogravimetric analysis and cone calorimeter, meanwhile the morphology of char residue and pyrolysis products were investigated to determine the flame retardant mechanism. As been confirmed, the deposition of bio- based polysaccharide onto the surface of PET fabric can effectively improve the thermal stability, flame retardancy and smoke suppression performance of PET fabric. The analysis of pyrolysis products and char residue demonstrated that the deposition of natural bio-based polysaccharide promoted the formation of dense carbon layer, thus protected bottom polymer and inhibited the pyrolysis process, improving the flame retardant properties.

Key words: chitosan, sodium alginate, polyester fabric, thermal stability, flame retardancy