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A rheological study of the order–disorder conformational transition of xanthan gum
Author(s) -
Pelletier E.,
Viebke C.,
Meadows J.,
Williams P. A.
Publication year - 2001
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/1097-0282(20011015)59:5<339::aid-bip1031>3.0.co;2-a
Subject(s) - rheology , differential scanning calorimetry , chemistry , dynamic mechanical analysis , thermodynamics , xanthan gum , superposition principle , extensional definition , time–temperature superposition , viscoelasticity , polymer , organic chemistry , physics , quantum mechanics , paleontology , tectonics , biology
The rheological properties of a moderately concentrated solution of xanthan gum in both the ordered and the disordered state have been studied. Oscillatory shear, steady shear flow, and extensional flow experiments have been performed at different temperatures, covering the order–disorder transition determined by differential scanning calorimetry (DSC). The principle of time/temperature superposition was applied to the xanthan solutions for the different types of flow. Although a master curve covering six decades of frequency could be obtained for the storage modulus over the entire investigated temperature range, less agreement was found for the other modulus. This indicates that the order–disorder transition reflects changes on the molecular scale and slight modification of the physical network structure. To the authors' knowledge, this is the first time that this transition has been observed using these different rheological techniques. © 2001 John Wiley & Sons, Inc. Biopolymers 59: 339–346, 2001