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

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 30°C. 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 ∝ 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 . © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 865–872, 2002