Formation of Irreversible Gels of Cellulose/Aqueous Calcium Thiocyanate Solution and Its Application to Wet Spinning.

Abstract

: We attempted to develop a high wet strength cellulose fiber using cellulose/aqueous calcium thiocyanate solution (aq.Ca(SCN)2) gel, as a precursor. The aq.Ca(SCN)2 showed a high dissolving power against several cellulose resources. The cellulose/aq.Ca (SCN) 2 gel generated using various organic and inorganic gelling agents were examined in terms of tenacity, elongation, and the morphology. From the results, it was found that rigid and homogeneous cellulose gels with low crystallinity were formed in a short time when ketones, such as acetone and methyl ethyl ketone, and alcohols, such as methanol and ethanol, were used as a gelling agent since aq.Ca (SCN) 2 is extracted from the cellulose solution. The wet spinning of the cellulose/ aq.Ca (SCN) 2 system was carried out using acetone or ethanol as a gelling agent. In both cases, we successfully obtained cellulose filaments with much higher tensile strength in conditioned and wet states than that of commercially available viscose and cuprammonium rayons for cloth uses.

Surface carboxylation of porous regenerated cellulose beads by 4-acetamide-TEMPO/NaClO/NaClO2 system

“…Water-soluble cellouronic acids Na salts were obtained from Bemliese by the oxidation under the conditions similar to those for the cellulose beads used in this study. This difference in oxidation behavior between the cellulose beads and Bemliese might be caused by different hydrophilicity of the solid cellulose surfaces and/or fine structures between them (Hattori et al 1999;Yamane et al 2006).…”

“…Isogai (&) Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan e-mail: aisogai@mail.ecc.u-tokyo.ac.jp CM-cellulose beads produced on the basis of the above principle are now commercially available. The Ca(SCN) 2 solvent gives regenerated cellulose fibers with quite high wet strength in comparison with other cellulose solvents (Hattori et al 1999). Moreover, when hydrophobic solvents such as hydrocarbons and toluene are used as the regeneration solvents, regenerated celluloses prepared from aqueous cellulose solutions have tendencies to form hydrophobic C-H planes of cellulose molecules facing to outside on the cellulose surfaces (Yamane et al 2006).…”