SYNTHESIS AND PROPERTIES OF MODIFIED XANTHAN GUM

Abstract

Xanthan gum is widely used as a stabilizing, emulsifying, thickening agent in pharmacology, medicine, food, oil, paint, textile, perfume, mining and agriculture. For food purposes, potassium, sodium or calcium salts of xanthan formed by carboxyl groups of glucuronic acid and pyruvate group are used. Currently, xanthan gum is not produced on an industrial scale in Russia. There are repeated attempts to create industries in various regions of the country. The paper synthesizes hydrophobized acetylated xanthan gum derivatives with different degrees of substitution. Physical-chemical and colloidal-chemical properties of initial and modified gum are compared by methods of viscosimetry, tensiometry, IR spectroscopy. The point of zero charge of xanthan gum is determined.. Change of macromolecule conformation depending on pH of aqueous solution and preliminary dewatering is shown. Delamination temperatures of initial and modified forms of xanthan gum were determined. The critical micelle formation concentration of the modified gum is 0.2%. At this concentration, the surface activity of the gum is 6.1 and 7.9 mJ m/kg when replacing two and five hydroxo groups, respectively. The possibility of using modified xanthan gum as a binder for obtaining fuel pellets with improved operational properties and calorific value is shown.