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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