An activation energy approach to analysing non-Newtonian slurry viscosities with application to a suspension of starch in a carboxymethylcellulose solution

•Viscosities determined for a suspension of starch in carboxymethylcellulose•Tests were at several, concentrations, temperatures and shear rates•Relative activation enthalpy independent of particle concentration•Shear rate results interpreted in terms of activation entropy•Positive entropy change implies increased disorder at higher shear rates

Many suspensions of practical importance exhibit non-Newtonian fluid behaviour. For a given particle concentration and temperature, these often have relative viscosities that vary with shear rate and this necessitates modifications to the frequently applied Krieger–Dougherty equation. A simple way to analyse viscosity data is by consideration of the activation energy. It is demonstrated as an example of the approach that the properties of a non-Newtonian suspension of starch in a carboxymethylcellulose solution may be described simply in terms of the activation entropy which can be interpreted as a semi- empirical measure of the degree to which structural re-arrangement occurs during flow.

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