Sodium lignin sulfonate: a bio-macromolecule for making fire retardant cotton fabric

Sodium lignin sulfonate (SLS) has been explored as a fire retardant finishing agent on cotton fabric. 30% [w/v] SLS treated cotton fabric has registered LOI value of 28.5 with minimum char length of 4 cm (self-extinguishment) whereas control cotton fabric was found to burn out with flame and afterglow within 1 min. Thermo-gravimetry of the treated cotton fabric showed 35% mass retention at 500 degrees C while only 8% char mass was left for the control cotton fabric at the said temperature. Volatile species liberated during burning were analyzed by GC-MS technique which demonstrated the restriction of flammable gas formation from the SLS treated fabric. Char mass left after burning also has been characterized in terms of its morphology, elemental analysis, etc. Moreover, it has also been proven that SLS treatment imparts a natural attractive yellow color, UV protective property to the treated fabric without altering physical strength of the fabric which can be considered as an added advantage over flame retardant effect. [GRAPHICS] .