Abstract: | The viscose rayon containing cyclotriphosphazene were prepared by the method of blending spinning. The combustibility and thermal stability of the fire‐retardant viscose rayon were evaluated by 45 ° slope burning method, limit oxygen index (LOI), differential scanning calorimetry, thermogravimetry analysis. The results indicated that the LOI of the modified fiber could reach LOI ≥ 28, and the combustibility of the modified fiber could reach the fire‐retardant standard of Japan industry standard JIS 10 91–77 (times of ignition ≥ 3 times). The analysis of the fiber's thermal degradation suggested that the flame retardant plays a multirole of heat absorption, catalytic dehydration and carbonization, condensation‐phase and gas‐phase flame retardation. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 698–702, 2006 |