The Study Of Dissolution And Regeneration Of Natural Fiber In Ionic Liquid

Natural fibers include plant fibers and animal fibers. They are concerned widely because of an abundant of source and can be renewable used. Ionic liquids are organic salts liquid at room temperature with advantages of low melting point, non-volatile, and adjustable structure. Based on the structural characteristics of the existing solvent that can dissolve natural fiber, ionic liquids which natural fibers can be dissolved in were synthesized. The cellulose produces were dissolved in ionic liquids and regenerated, then they were tested to explore the possibility and feasibility of recycled fiber.In this study, eight kinds of ionic liquids were produced at the first, and they were synthesized and characterized by means of FTIR,H-NMR techniques. Then four kinds of methods were used to activate cellulose, the activation of cellulose crystallinity, structure and surface morphology changes were analyzed by using X-ray diffraction, infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Finally, The properties of regenerated cellulose and silk were tested by X-ray diffraction, infrared spectroscopy (FTIR), polarizing microscopy, TGA, and the determination of degree of polymerization.It was found that a variety of activation methods can improve the solubility of cellulose, of which 18% sodium hydroxide activate affection was better. Ionic liquids can be a good solvent of natural fibers, by the testing of the dissolution capability of cellulose and Tussah silk elements in the synthesis of a variety of ionic liquids.It was found that four kinds of ionic liquids ([AMIM]Cl, [(MA)MIM]Cl, [BMIM]Cl and [EMIM]Ac)had relatively good dissolving effect. Especially in the [AMIM]Cl, natural cellulose (DP = 638) can be dissolved in a very short period of time with a 5-6% concentration, largest dissolution concentration of more than 14%.Through dissolution mechanism of cellulose dissolved in the ionic liquid, it was believed that natural fibers dissolved in ionic liquids are direct dissolution mechanism, but not derivatization reaction. By variety of means, the cellulose dissolved in the ionic liquid transformed from cellulose I to cellulose II. The molecular conformation of silk does not change compared to Tussah which B-sheet structure disappeared butα-helical structure appeared. The relationship between conformation and TGA changes behavior remains to be further studied. The polymerization of regeneration fibers will reduce to a certain extent degree.