Eco-friendly fire-retardant finishing of cotton fabric with mixture of ammonium sulfamate and sodium Stannate with and without zinc acetate as external reagent.

In this investigation, combination of ammonium sulfamate (AS), sodium stannate (SS) and zinc acetate (ZA) (as external reagent) was applied by simple double bath pad-dry-cure method to acquire fire-retardancy (FR) on cotton woven fabric. This chemical combination is eco-friendly as it neither releases taxic formaldehyde nor produces any bi-hazardous corrosive gases. During preliminary study with an aim to keep total added chemical around 20–30%, optimum FR result obtained at 16%AS + 8%SS + 5%ZA with a synergistic effect. Reaction mechanism showed that proton (H⁺ ion) developed from AS during heating, dehydrated the cellulose causing increase in char formation and other two chemicals (SS and ZA) formed protective coating on cotton. With this optimum chemical combination, limiting oxygen index value was achieved 38.30 with char length of 6.7 cm at 45° inclined plane flammability test but there was around 30% loss of fabric tenacity. The data obtained from thermo gravimetric analysis showed change in path of pyrolysis by lowering decomposition temperature with almost 29% increase in residual char formation indicating good FR property. Surface topography analysis by SEM, functional groups by analysis of FTIR, element identification by XPS confirmed surface deposition of these chemical compound along with agglomerated precipitation of "Zinc Hydroxy Stannate". During wash stability analysis, it was found that after application of 5% ZA, wash stability was better than without ZA after 10 wash cycles. [ABSTRACT FROM AUTHOR]