Hydroxypropylation of Guar Splits: Kinetics and Rheology

Hydroxypropyl guar (HPG) is one of the most important derivatives of natural guar gum. In this paper, we describe the hydroxypropylation kinetics when these functional groups are added to guar splits, which are the form of guar gum typically modified in an industrial process. NMR spectroscopy was applied to quantify the amount of reacted propylene as a function of reaction time. A kinetic model was then established, enabling the derivation of a reaction rate law for the hydroxypropylation of guar. Finally, we investigated the rheological properties of aqueous-phase HPG and its cross-linked derivatives as a function of propylene content and cross-linker amount.