Durable Flame Retardant Cotton Fabric Prepared by Partial Pyrophosphorylation and Metal Complexation

Abstract

In order to prepare durable flame retardant cotton, mercerized cotton fabric is treated with orthophosphoric acid at 140°C or pyrophosphoric acid at 110°C, followed by metal-complexation. The LOI (limited oxygen index) values of the pyrophosphorylated cotton fabrics are higher than those of orthophosphorylated fabrics; the pyrophosphory lated fabric treated with Ni 2+ has an LOI value of 28, and those treated with Ca2+, Mg 2+, or Zn2+ have a value of 26. The pyrophosphorylated fabric merely rinsed in running tap water has an LOI value of 26. These values are similar to those for cotton fabrics resin-finished with organophosphorus compounds. The LOI values of treated fabrics do not decrease after laundering, in contrast to the behavior of resin-finished fabrics. The pyrophosphorylated sample has a tensile strength, elongation, and hand similar to those of untreated fabrics, and is susceptible to enzymatic hydrolysis to release reducing sugars.