Research On LYOCELL Fiber Modified By Phosphorus-nitrogen Flame Retardant

Lyocell fibers are a kind of newly regenerated cellulose fibers,which are mainly composed of carbohydrates.Lyocell fibers are known as "green fiber" because of wear comfort,good dyeing,excellent air permeability,environmental friendly and rich in nature.Lyocell fibers burn fast when exposed to the flame.Therefore,the flammability characteristics greatly limit its applications in some fields.Therefore,improving the flame retardant properties of lyocell fibers have become a focus in the field of textile.First,the paper use a new type of halogen-free flame retardant to treat lyocell fibers by a simple and easy to conduct and one-step chemical finishing approach.Then lyocell fibers with excellent flame retardant properties were prepared.The combustibility,thermal stability and surface structures of control and treated lyocell fibers were discussed in detail.The results show that the resistance to combustion and carbon residue are significantly improved by treating lyocell fibers with EADP.The carbon residue of the flame retardant fibers after combustion increased up to 41.3%compared with that of control sample(15.7%).The surface structures of treated lyocell fibers did not show significant change,but many bubbles appeared in the surface of the treated lyocell fibers after burning.The heat release rate and total heat release also decreased obviously by micro cone calorimetry analyses.Secondly,a state-of-the-art flame retardant ATEPA with high contents of phosphorus and nitrogen elements were designed and synthesized.Lyocell fibers were treated by ATAFPA via repeated pad-dry-cure processes.The structure and properties of flame-retardant fibers are studied by a variety of analytical techniques,i.c.,infrared spectroscopy,thermogravimetry,scanning electron microscopy,microcoinical calorimeter,and etc.The results show that the introducing of flame rctardant has little effect on the morphology of modified fiber.Furthermore,the resistance to burning of treated lyocell fibers is significantly improved after being treated with ATAEPA.The results demonstrate that the modified lyocell fibers possess excellent flame retardancy.The probable flame-retardant mechanism of the fibers during combustion is proposed to be a combination of gas-phase flame-retardant and solid-phase flame retardant based on the analyses of coupled thermogravimetric-infrared technique and pyrolysis gas chromatography/mass spectrometry.