Preparation And Property Research On Chitosan Fiber Based On New Amino Acid Ionic Liquid

Chitosan has a lot of advantages such as biocompatibility, antibacterial property and easily absorbed by organism, so it is very suitably used in medical and textile industry. Till now, the preparation of chitosan fiber is still using volatile and difficulty recover solvent, which will cause corrosion in equipments, waste recourses and do harm to environment. As a result, finding a efficient and eco-friendly solvent for chitosan is of great importance for chitosan fiber industry. Ionic liquids (ILs) aroused wide concern for its excellent properties, and they had great solubility in chitosan, too. However, the high viscosity of ILs perhaps blocks the possibility to dissolve chitosan. In order to solve the problem, the aqueous solution of ILs is introduced in the dissolution of chitosan, which make them a kind of great solvent for chitosan.28 ILs have been prepared in the paper. The research of solubility on chitosan and the degradation rate of chitosan of different ILs were studied. [Thr][CH₃CH₂COO], [Pro][CH₃COO] and [Ser][CH₃COO] were selected as the best choice for dissoving chitosan. The mechanization of chitosan being dissolved in ILs aqueous solution has been discussed and put forward the theory that new hydrogen bonding between chitosan and ILs caused chitosan dissolving in ILs aqueous solution. Chitosan regenerated from ILs aqueous solution has been characterized by FT-IR,XRD and SEM to make sure the structure of chitosan did not change during the process of dissolution and regeneration.Acetic acid and ILs were used as solvent to dispose spinning dope. The composition and temperature of coagulating bath, water bath and stretch bath, draw ratio, and the additives etc. have been studied during the course of fiber-making on the spinning equipment. The result showed the best temperature of coagulating bath was 25℃, and alkali such as NaOH was good as coagulating bath. When the draw ratio was 1:1.4, the fiber was smoothest and perfect. The chitosan fiber containing additives had excellent breaking elongation. The breaking strength and breaking elongation of the chitosan fiber made in the experiments (1.801 cN/dtex and 11.69%) met the ideal value of fiber (1.0 cN/dtex and 10%) and was better than in CH₃COOH (0.863 cN/dtex, 15.79%). The ILs were successfully recycled and could meet the usage for at least 3 times.The paper used ILs aqueous solution as the solvent to prepare chitosan spinning dope and prepared chitosan fiber on spinning equipment. Soft and pale yellow fiber which has superior tenacity has been prepared and the ILs used in the experiment were recycled. The procedure avoided the contaminative way and supplied a green way to prepare chitosan fiber.