Change of Morphological Properties in Drawing Water-Swollen Cellulose Films Prepared from Organic Solutions. a View of Molecular Orientation in the Drawing Process

Drawable water-swollen cellulose films were prepared by coagulating in water two different cellulose organic solution systems. The drawability of the water-swollen films was dependent on the rate of coagulation. Transparent films prepared by the slow coagulation showed good drawability and had a maximum draw ratio of 2.0. However, the drawn films maintained the highly noncrystalline state even after dried at 50°C under vacuum. X-ray analysis and polarized FT-IR measurements performed under a saturated deuterium oxide vapor of these dried drawn films, prepared by slow coagulation, showed that their noncrystalline regions (more than 80%) as well as crystalline regions (less than 20%) were highly oriented by the drawing process. Furthermore, meridional intensity curves in the X-ray diffraction exhibited interesting patterns even though the drawn sample was highly noncrystalline. In fact, they are quite different from those in regenerated cellulose II fibers. However, despite this increase in draw ratio and in the orientation of the chains, the number of crystalline domains in the films did not increase significantly. This may perhaps be attributed to the three-dimensional network structure resulting from the intermolecular hydrogen bonds between chains which are maintained through the drawing process and which can hinder the crystallization of cellulose.