Effect of Sodium Ion on Flame Retardance and Thermal Degradation of Cellulose Fiber

Abstract

Flame retardance and thermal degradation of CMC-Na fibers were investigated using limiting oxygen index (LOI), thermal gravimetry (TG), differential TG (DTG) and Scanning electron microscopy (SEM). The LOI values of different CMC-Na fibers are 23, 26, 28.5, 31 and 34, compared with about 20 for viscose fiber. TG and DTG studies indicate that the temperature of maximum degradation rate and the maximum degradation rate for CMC-Na fibers are much lower than those of viscose fiber. However, CMC-Na fibers generate much more residues or carbonaceous char than does viscose fiber. The increase of sodium ion content, the carbon residual also increases. SEM studies of combustion residues after LOI testing indicate that all CMC-Na fibers produce intumescent, hard and brittle residue crusts.