The Study On The Solution Of Chitoson And Its Film-Forming And Stringiness In The Ionic Liquid

The chitosan film and fiber have attracted wildly attentions because of their excellence properties. The important process was the preparation of chitosan solution. Conventionally, the diluted acid was used as solvent in the process. The disadvantages of traditional technology were as follows: easy volatilization, difficult recycle and serious pollution. Therefore, it's time to find an effective green solvent to dissolution chitosan for the preparation of chitosan film and fiber. Ionic liquids were regarded as green solvents. At present, the dissolution research of chitosan mostly used pure ionic liquid as solvent. The obtained system was difficult to carry out deep treatment due to high viscosity. The significant problem was how to overcome high viscosity of dissolution system of chitosan. In this article, the obtained dissolution system of chitosan has lower viscosity with the ionic liquid aqueous solution as solvents. Therefore, a convenience method for the preparation of chitosan film and fiber is provided.Twenty-four kinds of ionic liquids were synthesized in this article. The different concentration aqueous solutions were prepared using these ionic liquids. The ionic liquid [Gly]Cl was of better solubility performance than the other ionic liquids through the comparison of chitosan soluble ability and performance. The structure was characterized by FT-IR, 1H-NMR and 13C-NMR. The structure of regeneration chitosan was characterized by FT-IR and XRD. The results indicated that chitosan did not reacted in the dissolution process. Therefore, the ionic liquid aqueous solution of [Gly]Cl was an excellent solvent to chitosan.The rheological property, film-forming and spinning capability of chitosan/[Gly]Cl ionic liquid aqueous solution were investigated and the recovery of ionic liquid was discussed. The results showed that the viscosity of chitosan solution was regulated through the increasing temperature and fit dosage of urea. The optimum conditions of film-forming and spinning process was obtained by the comparison of tensile strength and the SEM characterization. The homogeneous chitosan membrane with excellent properties was obtained when the weight percentage ration of glycerol and chitosan is 8-12%, the concentration of chitosan 2.0-2.5% and dry temperature 40℃. The optimum conditions of chitosan fiber with better performance were obtained as follows: the distance of air layer 3cm, jet stretch ratio 1.2-1.3, the concentration of chitosan 3.5%, the same volume of absolute alcohol and sodium sulfate(weight percentage is 3%) as coagulation bath and temperature 50℃.In this technique, the chitosan solution was prepared with ionic liquid aqueous solution as solvent. This process was low temperature, short time and low viscosity. The disadvantages of pure ionic liquids as solvents were avoided in this method. Meanwhile, a new green approach for film and fiber of chitosan is given.