Relationships between molecular structure and theology for xanthan, a naturally occurring, bacteria-produced cellulose derivative

Conference · Sat Jan 01 04:00:00 EST 1983 · J. Appl. Polym. Sci.: Appl. Polym. Symp.; (United States)

OSTI ID:7138753

Southwick, J G; Jamieson, A M; Blackwell, J

Quasielastic light scattering and other physical chemical techniques were used to compare the conformation and intermolecular interactions of xanthan in water, aqueous sodium chloride, and urea solutions. The results show that xanthan has a disordered conformation when dissolved in salt-free 4 M urea solutions, after they were maintained at 90/sup 0/C for 3 h and then cooled to room temperature. This conformation is similar to that observed previously only in low-ionic-strength solutions at higher temperature following disruption of the ordered low-temperature form. Anomalous behavior is seen for xanthan as a function of ionic strength, in that the hydrodynamic radius increases with increasing ionic strength, whereas a decrease is typical for polyelectrolytes. These observations suggest that aggregation of rod-like chains, similar to that seen for other stiff-chain polymers, occurs for xanthan in salt solutions, where the charged groups of the polyelectrolyte are screened by the salt ions. This aggregation may explain some of the high values of the molecular weight reported in the literature. 19 references, 4 figures, 3 tables.

• Research Organization: Shell Development Co., Houston, TX
• OSTI ID: 7138753
• Report Number(s): CONF-8205234-Vol.1
• Conference Information: Journal Name: J. Appl. Polym. Sci.: Appl. Polym. Symp.; (United States)
• Country of Publication: United States
• Language: English

Related Subjects

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ALKALI METAL COMPOUNDS
AMIDES
AQUEOUS SOLUTIONS
CARBOHYDRATES
CARBONIC ACID DERIVATIVES
CELLULOSE
CHLORIDES
CHLORINE COMPOUNDS
DISPERSIONS
HALIDES
HALOGEN COMPOUNDS
HYDROGEN COMPOUNDS
LIGHT SCATTERING
MIXTURES
MOLECULAR STRUCTURE
OPTICAL ACTIVITY
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXYGEN COMPOUNDS
POLYSACCHARIDES
RHEOLOGY
SACCHARIDES
SCATTERING
SODIUM CHLORIDES
SODIUM COMPOUNDS
SOLUTIONS
UREA
VISCOSITY
WATER
XANTHUM GUM