Intumescent flame retardant coatings on cotton fabric of chitosan and ammonium polyphosphate via layer-by-layer assembly

Intumescent flame retardant coating, composed of cationic chitosan and anion ammonium polyphosphate, has been constructed on cotton fabric by layer-by-layer assembly technique. The result of Fourier transform infrared spectroscopy confirmed that the assembly coating was successfully deposited on fabric and the coating quantity increased linearly with the growth of bilayer number. Evaluation of thermal and flammability properties showed increased residual chars at 700 degrees C in air during thermogravimetric analysis and decreased peak heat release rates and total heat releases in microscale combustibility test for the coated fabrics, as compared with the uncoated. Significantly, in vertical flame test the residues of the coated fabrics perfectly remained the textile structure and fiber shape with respectable strength, indicating that the intumescent coating show an excellent flame retardant efficiency on cotton. These results demonstrated a completely intumescent coating for cotton via layer-by-layer assembly technique which provides an effective alternative to phosphorus-based coating. (C) 2014 Elsevier B.V. All rights reserved.