VISCOMETRIC BEHAVIOR OF KEVLAR FIBER FILLED LIQUID-CRYSTALLINE SOLUTIONS OF ETHYL CELLULOSE IN M-CRESOL

Liquid crystalline solutions of ethyl cellulose in m-cresol were mixed with Kevlar fibres, and the viscometric behaviour with respect to temperature of those filled systems was determined with a cone-plate type viscometer. The viscosity of the systems exhibited a maximum and a minimum at temperatures denoted by Tmax and Tmin, respectively. The effects of fibre on the critical temperatures (Tmax and Tmin) and critical concentrations (Ca and Cb) and on the viscosity enhancement are discussed. Tmax and Tmin decreased with fibre concentration for single-phase anisotropic solutions, whereas they increased for the biphasic solution. The critical concentrations increased with fibre concentration and Cb was more sensitive to the fibre than Ca. The viscosity enhancement due to the fibre depended on the phase of solution. In the single-phase (isotropic and anisotropic), the viscosity enhanced with fibre; however, in the biphasic solution, the effect was not simple. The viscosity enhancement for the single-phase anisotropic solutions with fibre was lower than that for the isotropic solutions.