FLAME RETARDANT FINISHING OF COTTON FABRIC USING PHOSPHORUS-CONTAINING SILOXANE AND THERMAL STUDY
Sol-gel technique have been used to develop phosphorus-doped silica hybrid film on cotton fabric (CF) that improves its flame retardancy and stability. Phosphorus based compounds namely phosphoric acid, pyrophosphoric acid, and nitrilotris(methylene)triphosphoric acid solution were used with 3-aminopropyltriethoxysilane a sol-gel precursor for finishing of cotton fabric. FTIR spectrum confirms the presence of silane and phosphorus on treated fabric surface having additional stretching vibrations at 1238 cm-1 (P=O), 1052 cm-1 (Si–O–Si) and 810 cm-1 (Si-C). The limiting oxygen index value of a treated cotton fabric sample (CF-3P-SG) increased to 39.0% from 19.1% of untreated cotton fabric. The treated cotton fabric samples are extinguished instantly upon removal of the ignition source after 5s in Auto flammability test showing exceptional flame-retardant property. The char residue of CF-3P-SG sample increases significantly to 29.8% at 600ºC in thermogravimetric analysis in air atmosphere due to protective effect of phosphorus and nitrogen-containing sol-gel treatment of cotton fabric by favoring the formation of carbonaceous structure.