Theory of Flow Properties of Attapulgite Suspension in Water. A Method for Determining the Relaxation-Time Parameter β

Abstract

In two previous papers the stress-strain-time relations with respect to variables of temperature, concentration, and pH were given for attapulgite suspension in water, in terms of rheopexy (dilatancy) and thixotropy. Stress relaxation and script S-like curves showing both thixotropy and rheopexy were determined at various temperatures. Yield-point viscosities for the rheopectic and thixotropic curves showed activation energies of about 1 and 2 kcal, respectively. In the present paper Eyring's rate theory of viscosity is briefly discussed in terms of the well known generalized-viscosity equation η= ∑ i=1iXiβiαisinh−1βiṡβiṡ, which is applied successfully to given flow curves. A new method for determining the parameter βi is discussed.