Preparation and characterization of collagencoclotriphosphazene and its action in flame-retardant viscose fiber

In order to develop a flame retardant using the phosphazene derivative of a natural polymer, hexachlorocyclotriphosphazene and collagen were used as the raw materials to synthesize collagencoclotriphosphazene. The Fourier transform infrared results indicate that flame retardant collagencoclotriphosphazene(CGCP) was successfully synthesized. Thermal properties of CGCP were evaluated using thermogravimetry. The thermal analysis shows that the introduction of phosphazene into collagen lowered the primary decomposition temperature, increased the decomposition rate, and caused less weight loss. The viscose fibers blended by CGCP were prepared by the wet spinning method, and the properties of the fiber were investigated. Limiting oxygen index of the flame-retardant fiber containing 12% CGCP was 28.3%, which increased greatly comparing to the fiber sample without CGCP and just decreased slightly to 27.6% after 30 washing cycles. The thermal analysis shows that the introduction of CGCP increased the decomposition rate of viscose fiber at a lower temperature, and caused less weight loss. After burning, the scanning electron microscopy image showed an inflated carbonized coat on the fiber surface. The effect of CGCP on the mechanical properties of the fibers was insignificant. CGCP was compatible with cellulose, and the flame retardancy of the viscose fiber was significantly improved. Due to the introduction of CGCP, moisture regain of the fiber is a little higher than that of viscose fiber.