Opposite trends in thermodynamic compatibility between copolyamide and chitosan in their binary blend / Safronov Alexander P.,Suvorova Anna I.,Tyukova Irina S.,Smirnova Yelena A. // JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS. - 2007. - V. 45, l. 18. - P. 2603-2613.

ISSN/EISSN:

0887-6266 / нет данных

Type:

Article

Abstract:

Gibbs energy, enthalpy, and entropy of mixing in binary blends of chitosan with ter-copolyamide 6/66/610 at ambient conditions have been determined over the entire concentration range using thermodynamic cycle based on dissolution of individual polymers and their blends of different composition in a common solvent formic acid. Experimental procedure included stepwise equilibrium vapor sorption of glacial formic acid on the cast films and isothermal microcalorimetry of dissolution of these films in liquid glacial formic acid at 25 degrees C. Formic acid appeared to be a very good solvent for individual polymers and their blends. Flory-Huggins interaction parameter determined from sorption isotherms was negative and varied from -2.56 to -1.79 depending upon blend composition. The enthalpies of dissolution of individual polymers and their blends were strongly exothermic and varied from -200 to -40 Joule/g. Independent thermodynamic cycles for Gibbs free energy and enthalpy remarkably revealed similar trends in concentration dependence of different thermodynamic functions of mixing between chitosan and copolyamide. At high chitosan content, the binary blend is characterized by large and negative values of Gibbs free energy, enthalpy, and entropy of mixing that provide high polymer compatibility. On the contrary, at high copolyamide content the blends are incompatible and are characterized by positive values of enthalpy, entropy, and Gibbs free energy of mixing. Such complicated thermodynamic behavior is the result of the superposition of strong molecular interactions (H-bonds) between polymers in the blend and isothermal fusion of copolyamide crystallites. Thermodynamic analysis correlates well with the data obtained by polarized microscopy. (c) 2007 Wiley Periodicals, Inc.

Author keywords:

blending; calorimetry; chitosan; compatibility; polyamides; vapor sorption POLYMER BLENDS; STABILITY; EQUATION; LIQUIDS; STARCH; STATE

DOI:

10.1002/polb.20981

Web of Science ID:

ISI:000249704800009

Соавторы в МНС:

Другие поля

Поле	Значение
Month	SEP 15
Publisher	JOHN WILEY \& SONS INC
Address	111 RIVER ST, HOBOKEN, NJ 07030 USA
Language	English
Keywords-Plus	POLYMER BLENDS; STABILITY; EQUATION; LIQUIDS; STARCH; STATE
Research-Areas	Polymer Science
Web-of-Science-Categories	Polymer Science
Author-Email	alexander.safronov@usu.ru
Number-of-Cited-References	29
Usage-Count-Last-180-days	1
Usage-Count-Since-2013	4
Journal-ISO	J. Polym. Sci. Pt. B-Polym. Phys.
Doc-Delivery-Number	213ZC