Rheololgy of Mesomorphic Solutions of Cellulose

Solutions of cellulose were prepared with liquid crystal phases by mixing cellulose, water and N‐methylmorpholine N‐oxide under appropriate conditions of concentration and temperature. Their rheological behaviour was studied using capillary rheometry. For each solution, flow curves were plotted over a temperature range of 70‐‐120°C, and a shear rate range of 1‐‐500 sec−1. Considerable agreement was found between the rheological and optical characterisations of the anisotropic‐isotropic transition temperature T*. The variations of the strain rate sensitivity parameter m were studied over a large temperature range and particularly around T*. These results, new for cellulose solutions, provide some valuable information about the rheology of anisotropic polymer fluids.