Water activity of aqueous solutions of ethylene oxide-propylene oxide block copolymers and maltodextrins

Brazilian Journal of Chemical Engineering. 2010;27(1):173-181 DOI 10.1590/S0104-66322010000100015


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Journal Title: Brazilian Journal of Chemical Engineering

ISSN: 0104-6632 (Print); 1678-4383 (Online)

Publisher: Brazilian Society of Chemical Engineering

LCC Subject Category: Technology: Chemical technology: Chemical engineering

Country of publisher: Brazil

Language of fulltext: English

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N. D. D. Carareto
E. S. Monteiro Filho
P. A. Pessôa Filho
A. J. A. Meirelles


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Time From Submission to Publication: 12 weeks


Abstract | Full Text

The water activity of aqueous solutions of EO-PO block copolymers of six different molar masses and EO/PO ratios and of maltodextrins of three different molar masses was determined at 298.15 K. The results showed that these aqueous solutions present a negative deviation from Raoult's law. The Flory-Huggins and UNIFAC excess Gibbs energy models were employed to model the experimental data. While a good agreement was obtained with the Flory-Huggins equation, discrepancies were observed when predicting the experimental behavior with the UNIFAC model. The water activities of ternary systems formed by a synthetic polymer, maltodextrin and water were also measured and used to test the predictive capability of both models.