Durable Flame-retardant Finishing of Cotton with a Reactive Phosphorus-based Environmental Flame Retardant

A mannitol (MNT) - based reactive halogen-free flame retardant, FR-MNT, was synthesized and used for the flame-retardant finishing of cotton. FR-MNT was covalently grafted onto cotton fiber through -P = O(O-NH4+) groups, which endowed cotton fabric superior flame retardancy. Phosphorous acid was used instead of all phosphoric acid for esterification with mannitol, which reduced the amount of the -P = O(O-NH4+) groups, thus reducing the effect of metal ions on the flame-retardant fabric during soaping. Vertical combustion and LOI tests showed that treated cotton fabrics had excellent washing resistance. The thermal stability and combustion behavior of cotton fabric were evaluated by thermogravimetry (TG) and cone calorimetry tests. The mechanical properties of cotton fabrics changed only slightly after flame-retardant treatment.