Artículos de revistas
WATER ACTIVITY OF AQUEOUS SOLUTIONS OF ETHYLENE OXIDE-PROPYLENE OXIDE BLOCK COPOLYMERS AND MALTODEXTRINS
Fecha
2010Registro en:
BRAZILIAN JOURNAL OF CHEMICAL ENGINEERING, v.27, n.1, p.173-181, 2010
0104-6632
Autor
CARARETO, N. D. D.
MONTEIRO FILHO, E. S.
PESSOA FILHO, P. A.
MEIRELLES, A. J. A.
Institución
Resumen
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.