The Dissolution Of Natural Luffa Fibers And Its Regeneratd Spinning Properties

Luffa is an abundance and inexpensive natural polymer. Its physical structure of cellulose, hemicelluloses and lignin contents are very complex. To improve the use of cellulose, it must be pretreat to destroy their physical structure and achieve an effective separation of the cellulose, hemicelluloses and lignin. In this paper the alkali-hydrogen-peroxide. And hemicellulase were used for the pretreatments of luffa fibers. The purpose of pretreatments was to reduce the hindrance of lignin on the solution of cellulose and a high content of cellulose in the natural luffa raw materials. Regenerated cellulose films, wet-spinning fibers and electrospinning fibers were prepared successfully from pretreated luffa cellulose in [BMIM]Cl ionic liquid. The main conclusions of this article were as follows.The results of pretreatments showed that alkali-hydrogen-peroxide and hemicelluloses could effectively remove the luffa fiber surface’s lignin in a certain extent. The content of cellulose with alkali-hydrogen-peroxide pretreatment was80.51%. The content of hemicelluloses pretreatment was75.26%. With comparison and analysis of two methods showed that alkali-hydrogen-peroxide method was more effective. Then it was choosed as the pretreatment method of pretreated luffa fibers.The dissolving system research of luffa/phosphate anhydrous showed that the optimal conditions were as follows:the P2O5concentration in74%to76%, the concentration at12%and temperature at15℃. The regenerated cellulose film’s structures were analyzed by the SEM, XRD and FTIR. After dissolving in the anhydrous phosphoric acid, the cellulose crystalline form was changed from cellulose Ⅰ to cellulose Ⅱ. There was no derivative in above dissolving process.The dissolving system research of luffa/ionic liquid showed that the optimal pretreated luffa dissolution process was as follows:the dissolution rate of12%, dissolution temperature at80℃and dissolution time at12h. The studies showed that the ionic liquid [BMIM]Cl was a direct solvent of the luffa fibers. Compared to the luffa raw materials, the crystalline form of regenerated film and spun fiber were all transformed from cellulose Ⅰ to cellulose Ⅱ. Theirs thermal stability was not reduced and tensile strength was high relatively, the surface of files were smooth and with excellent wettability.Wet spinning was carried out at the laboratory homemade machine. The spinneret diameter was0.08mm, spinning temperature was90℃, and coagulating bath was deionized water. The pretreated luffa fibers were dissolved12h,80℃and5%cellulose. Electrospinning was carried out at5%luffa fiber and2.5%DMSO, plate spacing15cm, plate voltage20kV and anhydrous alcohol coagulating bath. The results of wet-spinning showed that the regenerated fibers were transformed from cellulose I to cellulose II and thermal stability decreased a little. Fiber surface was rough and had groove aspect or small holes of tending round shape. Hollow fibers got circular cross section. The structure was more compact. The fiber surface and cross-section structure were decided by the spinning conditions. The results of electrospun showed that the cellulose crystalline form had changed from cellulose I to cellulose II and there was no derivative in above dissolving process. But distribution of fiber diameter was uneven and discontinuity. The electrospun of luffa/[BMIM]Cl had a the feasibility in the future. But there was a great relationship with experimental conditions.