THE RHEOLOGICAL CHARACTERIZATION OF POLYMERIC AND COLLOIDAL FLUIDS

The rheological characterization of a number of industrial and consume r fluids is considered. Experimental measurements of the fluid's linea r viscoelastic, non-linear viscoelastic and steady shear response are presented. A model originally developed for the description of polymer melts is then extended to test its applicability on an associative th ickener, shampoo, a liquid crystalline polymer, tomato ketchup, an oil -based paint, and a kaolinite slurry. The oscillatory linear viscoelas tic data are fitted to a discrete set of Maxwell elements and the non- linear step-strain data to a Wagner-type damping function. A factored time and strain dependent constitutive equation is then found in gener al to predict adequately the non-linear steady shear response. The rhe ological scheme has useful potential both for characterization and num erical prediction of engineering and processing flows.