Crystalline characteristics of cellulose fiber and film regenerated from ionic liquid solution.

Regenerated cellulose fiber, fiber extrudate, and film were produced from cellulose solution prepared with raw pulp and ionic liquid solvent 1-butyl-3-methylimidazolium chloride ([BMIM]Cl). Spinning setting was based on a dry-jet and wet-spun approach including extrusion, coagulation, drawing, drying, and winding. Crystallization of the experimental fiber, fiber extrudate, and film was evaluated using a technique of wide angle X-ray diffraction (WAXD). Crystallinity index, crystallite size, and crystal orientation factor were calculated and compared among these samples. Influence of die shape, die dimension, and drawing speed on the regenerated cellulose crystallinity was discussed. The study indicated that the pulp cellulose was a Cellulose I type structure. The cellulose regeneration from the [BMIM]Cl solution completed a transformation from this intermediate phase to a final Cellulose II phase. The die shape and dimension and drawing speed were all important factors affecting the crystallinity of regenerated cellulose fiber and film.