RHEOLOGICAL STUDY OF CONCENTRATED DISPERSIONS IN BINARY LIQUIDS

Rheological data for concentrated dispersions of particles in polyethers of different molecular weight are presented and analyzed by using Eiler's maximum packing volume fraction concept. While the dispersion medium may affect the degree of dispersibility, the theoretical maximum packing volume fraction is ultimately governed by properties of the particles. For a given packing volume fraction, the viscosity of a dispersion must be a function of the medium viscosity. A binary liquid medium can be used to furnish desirable viscosity and chemical characteristics of the dispersion. However, the viscosity of the binary polymeric liquid system cannot be predicted by the Kendall logarithmic summation equation. A modified predictive analysis, based on critical “hole” size, is presented, with examples. © 1990, American Chemical Society. All rights reserved.