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

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.