Synthesis and Properties of Modified Xanthan Gum

Xanthan gum is widely used as a stabilizing, emulsifying, thickening agent in pharmacology, medicine, food, oil, paint and varnish, textile, perfumery, mining industry and agriculture. For food purposes, potassium, sodium or calcium salts of xanthan are used formed due to carboxyl groups of glucuronic acid and the pyruvate group. At present, xanthan gum is not produced on an industrial scale in Russia. There are numerous attempts to create the production facilities in different regions of the country. In this work, hydrophobized acetylated xanthan gum derivatives with various degrees of substitution were synthesized. A comparison of physicochemical and colloid-chemical properties of the initial and modified gum was carried out by viscometry, tensiometry, and IR spectroscopy methods. A point of zero charge of xanthan gum was determined. A change in the conformation of macromolecules depending on pH of water solution and preliminary dehydration was demonstrated. Separation temperatures of the initial and modified forms of xanthan gum were determined. The critical concentration of micelle formation of the modified gum is 0.2%. At this concentration, the surface activity of gum is 6.1 and 7.9 mJ m/kg when substituting two and five hydroxo groups, respectively. The possibility of using the modified xanthan gum as a binder for the production of fuel pellets with increased performance properties and calorific value was demonstrated.