Xanthan is a natural polymer used by Chemtotal as an additive in food, soil erosion control, oil-field applications, mining, etc..
Generated by the bacteria Xanthamonas Campestris and produced commercially by a fermentation process, the Xanthan gums are composed of three monosaccharides – mannose, glucose and glucuronic acid, arranged in a highly branched structure with an estimated molecular weight of 5 million.
Xanthan’s polar side chains provides sites for extensive hydrogen bonding with water and interactions between polymer chains that give rise to a helical structure in solution. This type of structure allows for a significant increase in solution viscosity especially at low shear rates.
The physical properties of the Xanthan gums have lead to their use in a variety of applications. Readily soluble in hot and cold water these gums brine over a wide pH range. In aqueous solutions, the polymer is highly pseudoplastic and shows stability to moderate temperatures and pH changes.
The Xanthan gums are mainly used in the petroleum industry additives for drilling fluids. The “scaffolding” structure presented by Xanthan makes these gums excellent suspending agents to carry cuttings from drilling operations. Xanthan’s rheological properties are particularly well suited to this application in that it is pseudoplastic and has high viscosity while at rest. Because of this high viscosity, a certain amount of stress on the fluid is high viscosity while at rest. Because of this high viscosity, a certain amount of stress on the fluid is required to initiate flow. The amount of stress required to initiate flow is known as the yield point.