| The guar gum is a polysaccharide originated from the seed endosperm in India and Pakistan. It is extracted from cyamopsis tetragonolobus' seed and belongs to galactomannan. It is one of present known best water-soluble compound of natural polymers. Pure and modified guar gums are widely used as thickeners or protective colloids in the food, textile, petroleum and mining industries. However, it has a few shortcomings, such as slowly to dissolve. so it is often chemically modified to improve its physical and chemical properties. In this work, 2,2,6,6-tetra methyl-1-piperidinyloxy radical (TEMPO)-mediated oxidation of guar gum' and hydroxypropyl guar gum was studied with NaOCl as the primary oxidant. The introduction of additional carboxylate groups along the polymer chain is expected to improve the properties of this polysaccharides.Two phases were observed from typical kinetic plot of TEMPO-mediated oxidation of guar gum as monitored by the consumption of NaOH. From the IR spectra, the absorption bands of the C=O was observed in the 1615cm-1 while it shifted to the 1739cm-1 after acidifying the samples. It indicate that the absorption bands of oxidized guar gum is -COOH group. From 13C-NMR spectra the fact that the carboxylate resonate could be found at near 175 ppm indicates that the hydroxyl of C6 was oxidized to -COOH. But no resonance in the 198-210 ppm region was observed, indicating no ketone group formation during the oxidation.
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