Novel fibers spun from cellulose in anisotropic phosphoric acid solution

Liquid crystalline solutions of cellulose were prepared in a kneader by mixing cellulose and phosphoric acid/poly-phosphoric acid solution. The composition of solvent is expressed in a P2O5 concentration. Influence of P2O5 concentration of compound solvent on solubility and dissolution behavior of cellulose was evaluated. The experiment results indicated that the P2O5 concentration could play an important role in breaking the intra- and inter-molecular hydrogen bonding of cellulose and increasing the expanding extent of the cellulose molecules chains. Based on these experiment results, dissolution process and mechanism were depicted. Moreover novel regenerated cellulose fibers have been successfully spun from this cellulose dope. The tensile strength, elongation at break and crystallinity index of the novel fibers were measured to be 5.35 cN/dtex, 3.97% and 50%, respectively, revealing good mechanical properties. The structure of fibers was analyzed by using C-13 NMR, wide-angle X-ray diffraction (WAXD) and FT-IR spectroscopy. The experiment results show that the cellulose I family crystal structure transferred to cellulose II family crystal structure during the regeneration process of the fibers. This technology is simple, cheap, and environmentally friendly, promising to substitute for viscose rayon production having hazardous byproducts.