Dissolution Analysis Of Cotton Stalk Fibers In Ionic Liquids

China produced most of the cotton in the world, but vast majority of the cotton stalk was discarded without further utilization. Cotton stalk fiber is a kind of natural fiber with cellulose,hemicellulose, lignin and pectin in different proportion, which could not be used for garment directly. After regeneration, properties of regenerated cotton stalk fiber are significantly improved. However, amount of lignin and other impurities ought to be diminished to obtain better spinnability. This work provided an in-depth research on regeneration of cotton stalk into membrane and fiber. Degumming conditions are optimized through orthogonal experiment with alkali-hydrogen peroxide method under high temperature and high pressure.Degummed cotton stalk fiber was dissolved in 1-butyl-3-methyl imidazole chloride and1-ethyl-3-methyl imidazole acetate respectively and effects of time, temperature and cellulose content on dissolution were discussed. As prepared regenerated cellulose solution was then molded to prepare membrane with wool keratin solution to analyze spinnability of regenerated cellulose. Main conclusions are listed below.Alkali-hydrogen peroxide method is effective in removal of impurities of cotton stalk fiber under high temperature and high pressure. With optimized conditions of sodium hydroxide(20%) and sulfidity(22%) under 170℃ for 100 min, cellulose content could be up to66.76% and lignin content no more than 1.66%.It can be learn from the experiment of dissolving cotton stalk in ionic liquid that dissolution increases with cellulose content. Besides, long time and high temperature can accelerate the dissolving process in a extent and finally reaches its equilibrium. The best dissolving conditions were chosen as temperature of 120℃ for 11 h.No changes are found in FTIR spectra of regenerated cellulose membrane with wool keratin during dissolving and regeneration process, indicated that there is no chemical change in the regeneration process. Small shift of characteristic diffraction peak of cellulose in XRD patterns suggest that it’s a transformation of crystal structure. Results of property test presentsthat regenerated membrane has admirable wettability and breaking strength could be up to16.7Mpa with 100% of cellulose.Regenerated cellulose and blend fibers are obtained via electrostatic spinning, space between polar plates 15 cm, voltage of polar plate 20 kv and alcohol is used as coagulation bath. SEM graphs shows that surface of blended fibers is much smoother than cellulose fibers,and diameter is evenly distributed.