The nature of thermodynamic compatibility of components of aqueous solutions of starch and cellulose carboxymethyl derivatives / Safronov A. P.,Tyukova I. S.,Suvorova A. I. // POLYMER SCIENCE SERIES A. - 2009. - V. 51, l. 2. - P. 174-181.

ISSN/EISSN:

0965-545X / нет данных

Type:

Article

Abstract:

The Gibbs free energy, enthalpy, and entropy of mixing of starch and carboxymethyl derivatives of starch and cellulose with water were determined by sorption and calorimetry methods at 25A degrees C throughout the entire range of compositions. The contributions due to the equilibrium intermolecular interactions and relaxation of a metastable glassy structure were separated. The relaxation of the metastable structure taking place during physical adsorption of the first portions of water on polymers makes a negative contribution to all thermodynamic functions of mixing. The contribution of equilibrium interactions, which includes pair nonviolent interactions of units and water molecules and electrostatic interactions of ions, is positive for the enthalpy and entropy of mixing. In this case, the positive entropy values exceed those of enthalpy, which is responsible for the thermodynamic compatibility. Thermodynamic analysis of the processes of dissolution of starch, carboxymethyl starch and carboxymethyl cellulose sodium salts showed that, contrary to the popular point of view, the compatibility of polysaccharides and their derivatives with water is based not on the enthalpy, but entropy nature and is strengthened additionally owing to relaxation of the metastable glassy structure of polymers.

Author keywords:

WATER SYSTEMS; POLYMER; FLUCTUATIONS

DOI:

10.1134/S0965545X09020059

Web of Science ID:

ISI:000264266000005

Соавторы в МНС:

Другие поля

Поле	Значение
Month	FEB
Publisher	MAIK NAUKA/INTERPERIODICA/SPRINGER
Address	233 SPRING ST, NEW YORK, NY 10013-1578 USA
Language	English
Keywords-Plus	WATER SYSTEMS; POLYMER; FLUCTUATIONS
Research-Areas	Polymer Science
Web-of-Science-Categories	Polymer Science
Author-Email	Irina.tyucova@usu.ru
Funding-Acknowledgement	Russian Foundation for Basic Research {[}04-03-96087]
Funding-Text	This work was supported by the Russian Foundation for Basic Research (project no. 04-03-96087).
Number-of-Cited-References	22
Usage-Count-Since-2013	1
Journal-ISO	Polym. Sci. Ser. A
Doc-Delivery-Number	420CM