Abstract:

Guar gum was modified by the cross-linking in order to improve its properties and broaden its applications.
The technology conditions for preparing the cross-linked guar gum were explored by using guar gum as the raw materials,
phosphorous oxychloride as a cross-linking agent, sodium hydroxide as a catalyst and ethanol as a solvent. The effects of the
reaction temperature, reaction time, amount of phosphorous oxychloride and pH on the sedimentation volume of the crosslinked
guar gum were investigated. On the basis of one-factor-at-a-time design, the response surface methodology was used
to optimize the process parameters of the cross-linking. The order for influencing the guar gum cross-linking from primary
to secondary was as follows: the amount of phosphorous oxychloride, reaction time, reaction temperature and pH. The best
reaction conditions for preparing the cross-linked guar gum were: the amount of phosphorous oxychloride 1.2%, reaction
time75 min, reaction temperature 33 ℃, pH 11.5. The sedimentation volume of the cross-linked guar gum was 1.03 mL
under the optimal conditions.

Key words: guar gum, cross-linking, phosphorous oxychloride, preparation, response surface methodology