PREDICTING STEADY AND OSCILLATORY SHEAR RHEOLOGICAL PROPERTIES OF CMC/GUAR BLENDS USING THE BIRD-CARREAU CONSTITUTIVE MODEL |
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Authors: | JOSEF L KOKINI GARY J PLUTCHOK |
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Affiliation: | Rutgers University New Jersey Agricultural Experiment Station Cook College Food Science Department New Brunswick, New Jersey 08903 |
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Abstract: | The Bird-Carreau constitutive model, a five parameter semi-empirical set of equations, was used to predict the steady shear viscosity η, the dynamic viscosity η', and the out-of-phase component of the complex viscosity divided by frequency η"/ω, for aqueous blends of sodium carboxymethylcellulose (CMC) and guar gum. The five Bird-Carreau constants were derived from equations which correlate the constants to concentration and molecular weight of the CMC/guar blends. Blends of ratios 3:1, 2:1, 1:1, 1:2, and 1:3 by weight were studied in concentrations of 0.5, 0.75, 1.0, and 1.5% by weight. For most blends the model accurately predicted the experimental η and η' data in the frequency/shear rate range of 0.1–100 s-1 and the experimental η"/ω data in the frequency/shear rate range of 1.0–100 s?1. |
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