REGENERATION OF CELLULOSE FROM LIQUID SULFUR DIOXIDE SOLUTION AND SOME PROPERTIES OF THE REGENERATED CELLULOSE

Abstract

In the previous paper, it was reported on the preparation of cellulose liquid sulfur dioxide solution in the presence of secondary or tertiary amines. In the present work, cellulose is regenerated from cellulose-triethylamine-liquid sulfur dioxide solution in a form of the model filament under various conditions. Some properties of these filaments were investigated comparing with those of viscose model filaments.Clear and uniform filament was obtained by dry spinning in cooled atmosphere or wet spinning using cooled methanol (-10°C) as coagulating and regenerating bath. Meanwhile, in the case of wet spinning using acetone or NaCl-HCl aqueous solution (-10°C), cellulose was regenerated as milky white and non-uniform filament. From the above observations, it is clear that phat physical conditions such as the elimination of sulfur dioxide in the coagulating bath have an extremely great effect on the characteristics of these filaments.The characteristics of the fine structure of the model filaments were studied by X-ray diffraction water and Iodine sorption methods. From these examinations, it is recognized that the filament regenerated in methanol or acetone is highly accessible (crystallinity: 12_??_18%, accessibility: 89_??_93%. calculated from water sorption data), and the X-ray diffraction pattern is similar to that of amorphous cellulose, while the filament regenerated in water is less accessible than the filaments regenerated in methanol or acetone (crystallinity: about 26%, accessibility: about 86%). Therefore, it is confirmed that the regenerated cellulose from liquid sulfur dioxide solution is more amorphous comparing with viscose model filament (crystallinity: about 34%, accessibility: about 81%).These fresh filaments are also anisotropical for the shrinkage (the degree of shrinkage to the cross direction for fibre axis: 50_??_60%, longitudinal direction: 26_??_37%). While cellulose is coagulated by the elimination of sulfur dioxide, the cellulose gel may shrink to the cross direction for fibre axis, and consequently these filaments may have the above anisotropical property.