Chemical modification and solution viscosity characteristics of Xanthan gum

Xanthan gum-OH and maleic anhydride were esterified to produce the modified Xanthan gum MX with better viscosity characteristics. The best conditions for reaction are: molar ratio of XG and MA is 1 ∶11; the temperature is 70℃ and reaction time 24h. MX has better solubleness and dispersity compared with XG. When the polymer concentration increased from 7 to 8g·L-1, the viscosity went up to 240mPa·s, while MX70 viscosity increased 582mPa·s; in the 1.2% NaCl solution, viscosity of 2g·L-1MX70 is 234mPa·s, while XG 95mPa·s. In the3g·L-1aqueous solution, when pH=4, viscosity of MX70 is 284mPa·s, while XG 178mPa·s. when pH=11, viscosity of MX70 is 262mPa·s, while XG 178mPa·s; In the 3g·L-1aqueous solution, when the temperature increased from20℃ to 80℃, the colloidal viscosity turned down in proper order. However, the scale of decrease of MX70 viscosity is 18.7% less than XG. The hydrotropy of modified Xanthan gum MX is good. And the solution viscosity has increased remarkably. The ability of temperature resistance and salt tolerance has also been strengthened. It is of great importance to the research and application of oilfield drilling fluid tackifier.