New binary ionic liquid system for the preparation of chitosan/cellulose composite fibers

A binary system consisting of acidic ionic liquid glycine hydrochloride (Gly·HCl) and neutral ionic liquid 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) is proposed to be cosolvent for chitosan and cellulose, the spinning solution of chitosan/cellulose can be prepared in one step. The regenerated chitosan/cellulose composite fiber with 9.4 wt.% chitosan was prepared through dry–wet spinning process. SEM shows that the chitosan is scattered on the surface and interior of the composite fiber. WAXD shows that the degree crystallization of the composite fibers is far less than that of raw materials. The result of elemental analysis (EA) indicates that there is little weight loss of chitosan during the spinning process. Moreover, the prepared composite fiber presents good thermal stability, i.e. its Tonset is 305.1 °C, and excellent mechanical property, i.e. its tensile strength is 4.63 cN/dtex. All the results show that Gly·HCl/[Bmim]Cl binary system is a promising solvent for the preparation of chitosan/cellulose composite fiber.

► A binary solvent system presents strong dissolving power for chitosan and cellulose.
► The spinning solution including chitosan and cellulose can be prepared in one step.
► The prepared composite fibers via solution spinning present good mechanical property.