RHEOLOGY OF AGGREGATED POLYSTYRENE LATEX-GELATIN DISPERSIONS

The diameter of aggregates of a polystyrene latex-gelatin dispersion w as calculated from theological data. An anomalous increase in the diam eter of aggregates with an increase in temperature was attributed to t he prevailing role of variation in the viscosity of the dispersion med ium with temperature, as compared to other effects. By substituting th e experimental data into Batchelor's equation, it was found that, even at a high shear rate (epsilon approximate to 1300 s(-1)), the disinte gration of aggregates to single particles is incomplete, and the dispe rse system contains both particles and aggregates. The combined effect ive concentration of the particles and aggregates was estimated to be approximately tenfold higher than the actual concentration of the indi vidual particles used in this study (4.8%). Hence, ultimate breakdown of the structure does not occur under high-rate shear deformation.