Preparation And Properties Of Cellulose Antibacterial Fiber By Ionic Liquid/co-solvent Plasticization

The annual production of cellulose is more than 200 billion tons,which has the largest reserves in nature.Ionic liquids have the characters of strong cellulose dissolving capacity and are used as the solvent for cellulose.However,the viscosity of ionic liquid and cellulose/ionic liquid is high,which is disadvantage for preparation,transportation and extrusion of spinning solution.In this dissertation,dimethyl sulfoxide(DMSO)was chosen as the co-solvent for cellulose/1-ethyl-3-methyl imidazole chloride([EMIM]CI)system.The solution of cellulose/[EMIM]Cl/DMSO was prepared.The rheology of cellulose/[EMIM]CI]/DMSO was studied.The pattern of cellulose movement and the effect of DMSO in the solution were discussed.The suitable content of DMSO in the solution was found which is reasonable for spinning.The twin screw was used for plasticization and the single screw was chosen for spinning,the effect of cellulose on the structure and property of cellulose fibers was studied.Seven ionic liquids including imidazole cation and thiazole cation were filtrated to dissolve chitosan.The cellulose/chitosan derivative blend fiber was prepared by two screws.The effects of chitosan derivative on spinning solution and the mechanical and antifungal properties were studied,which laid the theoretical foundation for the industrialization of the antibacterial cellulose fiber.Firstly,the rheology property of cellulose/[EMIM]Cl/DMSO solution was studied.The effects of different DMSO contents and temperatures on the viscosity and modulus were analysised.The complex viscosity decreased with the increase of DMSO in the solution.But the entanglement network structure of cellulose remains.The viscosities of cellulose/[EMIM]Cl/DMSO solutions obey the Cox-Merz rule.[EMIM]Cl/DMSO is solvent for cellulose at this temperature of 25?.It is good solvent for cellulose at the temperature of 100?.The high concentration of cellulose/[EMIM]Cl/DMSO solution was successfully prepared by twin screw.The solution is anisotropic at room temperature which can be kept for a long time.The spinning test of orthogonal experimental results within the scope of the test influence orders show that:the screw rotation speed>the air gap>fiber content>spinning temperature.The DMSO decreases the viscosity of the solution which benefits for the transformation and extrusion of the solution.However,the strength of the fibers decreases with the increase of DMSO in the solution.When the content of DMSO is above 30%,the strength of the cellulose fibers keep constant.Seven different ionic liquids,[EDIMTZ]Br?[BDIMTZ]Br?[BIBTZ]Br?[HMIM]HSO4?[(CH2)4SO3Hpy][HSO4]?[(CH2)4SO3HMIM][HSO4]?[IMIM-COOH]Cl were syntheticd.[(CH2)4SO3Hpy][HSO4]?[(CH2)4SO3HMIM][HSO4]and[IMIM-COOH]Cl aqueous solutions can dissolve chitosan.Considering the decomposition of cellulose under the acidic condition,the carboxymethyl chitosan and ionic liquid[EMIM]Cl/DMSO were used to dissolve cellulose,the cellulose/carboxymethyl chitosan blend fiber was fabricated by dry-jet wet spinning and showed good antibacterial properties.