Recoverable shear strain of liquid crystal-forming concentrated hydroxypropyl cellulose solutions

摘要

The recoverable shear strain (S-R) for the liquid crystal-forming hydroxypropyl cellulose solutions was determined by means of a concentric cylinder rotational apparatus as functions of shear stress prior to recovery and concentration of the solutions at 30degreesC. S-R greatly depended on shear stress and concentration; the phase of the solution (the single phase or biphase) governed the dependences of S-R on stress and concentration. S-R increased with increasing stress for the single phase and decreased for the biphase. S-R seemed to be related to the die swell (B): S-R alpha B-n. S-R exhibited a maximum and a minimum with respect to concentration. S-R for the cellulosic cholesteric liquid crystalline solutions was greater than that for the isotropic solutions. A model was proposed for explaining the greater S-R. (C) 2002 Wiley Periodicals, Inc. [References: 23]