Primarily Industrialized Trial of Novel Fibers Spun from Cellulose Dope in NaOH/Urea Aqueous Solution

Faced with the serious pollution caused by the viscose method (use of CS2), a primarily industrialized trial via a "green" wet-spinning process based on dissolution of cellulose in NaOH/urea aqueous solution precooled to -12.5 degrees C was performed. In a dissolution tank of 1000 L capacity, the cellulose could be dissolved completely in the NaOH/urea system within 5 min, and cellulose fibers were spun successfully from the transparent dope. A 15:10 H2SO4/Na2SO4 aqueous solution was adopted as the first coagulants in the bath, and a 5 wt % H2SO4 aqueous solution was used as the second coagulant to fabricate new regenerated cellulose fibers. There was no evaporation of any chemical agent during dissolution and regeneration. The structure of the fibers was characterized with scanning electron microscope, wide-angle X-ray diffraction, C-13 NMR, and tensile testing. The cellulose fibers exhibited a bright surface and a circular section, and their tensile strength reached 1.63-1.97 cN/dtex, which is close to commercial viscose fiber, although the drawing orientation in the production process was not performed. Therefore, we created a novel and simple approach combining a nonpolluting, low-cost, and quick process for the production of cellulose fibers, which was important for environmental conservation.