Non-soluble Silicate Retardant Viscose Fiber

Cellulose, the most abundant natural polymer material in the earth, is the main component of viscose fiber. Viscose fiber, with good water-absorbing quality, is comfortable to wear and liked by people. However, viscose fiber is flammable which limits its application greatly. In order to get flame retardant performance, viscose fiber with different metal were prepared through adding insoluble silicate into viscose.The flame retardancy of viscose fiber with and without metal ions were analysed by LOI and CONE. The flame retardancy of four metal ions was compared. It was found that addition of insoluble silicate could increase the LOI value of viscose fiber. The heat release rate and total heat release of retardant viscose fiber were significantly decreased after addition of insoluble silicat, thus the fiber obtained outstanding flame retardant properties.The burning residues of flame retardant fiber were characterized by scanning electron microscope (SEM). The photographs indicated that a compact physical barrier layer was formed by metal salt together with carbon. X-ray diffraction (XRD) results proved that the salts involved in chemical reactions demonstrated obvious flame retardancy on viscose fiber.TG measurement revealed that the degradation temperature of cellulose increased and metal ions changed the pathway of cellulose pyrolysis to produce more small molecular gas and char. This increased the yield of residues.To solve losses of metal ions in the clotting bath, an improved technology was explored. Fiber prepared by this process contained more metal ion than before and better flame retardance.