THERMODYNAMIC STUDY OF POLY(N-VINYL CAPROLACTAM) HYDRATION AT TEMPERATURES CLOSE TO LOWER CRITICAL SOLUTION TEMPERATURE / TAGER AA,SAFRONOV AP,SHARINA SV,GALAEV IY // COLLOID AND POLYMER SCIENCE. - 1993. - V. 271, l. 9. - P. 868-872.

ISSN/EISSN:

0303-402X / нет данных

Type:

Article

Abstract:

The lower critical solution temperature of aqueous solutions of poly(N-vinyl caprolactam) falls in the 305-307 K range and depends on the molecular weight of the polymer. The thermodynamic functions of mixing at 298 K have been calculated from measurements of vapor pressures and heats of dissolution and dilution. Partial Gibbs energy, partial enthalpy, and partial entropy of mixing were negative over the entire range of composition. Increasing temperature resulted in a decrease in the exothermal character of mixing. Excessive heat capacity values, calculated from the dependencies of enthalpy of mixing on temperature, were positive over the entire composition range. Heat capacity of dilute solutions was measured at 298 K and partial heat capacity of poly(N-vinyl caprolactam) at infinite dilution was shown to be positive. The data obtained point out the hydrophilic and hydrophobic hydration of poly(N-vinyl caprolactam) in aqueous solutions. Hydrophobic hydration dominates at temperatures close to binodal curve. As a result, the mutual mixing of the polymer with water is decreased and phase separation takes place.

Author keywords:

POLY(N-VINYL CAPROLACTAM); LOWER CRITICAL SOLUTION TEMPERATURE; THERMODYNAMICS OF POLYMER HYDRATION POLYSTYRENE SOLUTIONS

DOI:

10.1007/BF00652769

Web of Science ID:

ISI:A1993LY69000007

Соавторы в МНС:

—

Другие поля

Поле	Значение
Month	SEP
Publisher	DR DIETRICH STEINKOPFF VERLAG
Address	C/O SPRINGER-VERLAG, HEIDELBERGER PLATZ 3, 1000 BERLIN 33, GERMANY
Language	English
Keywords-Plus	POLYSTYRENE SOLUTIONS
Research-Areas	Chemistry; Polymer Science
Web-of-Science-Categories	Chemistry, Physical; Polymer Science
Number-of-Cited-References	16
Usage-Count-Since-2013	12
Journal-ISO	Colloid Polym. Sci.
Doc-Delivery-Number	LY690