Effect of condensed‐phase and gas‐phase flame retardants on the ignition behaviour of cotton fabric

The purpose of this study is to evaluate the effect of some well-known flame retardants on the ignition behaviour of cotton fabric. Two types of flame retardants acting in different phases (e.g. condensed phase and gas phase) were used. At low add-on of the retardant acting in the condensed phase the ignition behaviour of the cotton is different from that treated with retardant acting in the gas phase. The condensed-phase retardant caused cotton to burn more rapidly than untreated fabrics. This was attributed to the fact that small add-on of the retardant makes the fuel for the flame available at a lower temperature. However, in the presence of sufficient amounts of retardant, the decomposition of cellulose becomes more directed towards the dehydration mechanism and thus the concentration of the flammable gases is insufficient to reach the flammability limits required. When gas-phase flame retardants were used, a linear dependency of ignition time on the concentration of additive was found. This is explained in terms of the dilution effect of this retardant on the fuel produced from the decomposing fabric.