Synthesis, characterization, and swelling studies of guar gum-based pH, temperature, and salt responsive hydrogels

Properties of galactomannans and their textile-related applications-A concise review

Galactomannans are reserve carbohydrates in legume plants and are primarily extracted from their seeds. They contain galactose side chains throughout the mannose backbone and have unique features such as emulsifying, thickening, and gelling together with biodegradability, biocompatibility, and non-toxicity, which make them an appealing material. Guar gum and locust bean gum mainly are used in all galactomannan needed applications. Nonetheless, tara gum and fenugreek gum have also attracted considerable attention in recent decades. Despite the increased usage of galactomannans in the textile-related fields in recent years, there is no review article published yet. To fill this gap and to demonstrate the striking and increasing importance of galactomannans, a concise summary of the properties of common galactomannans and their comparisons is given first, followed by an account of recent developments and applications of galactomannans in the textile-related fields. The associated potential opportunities are also provided at the end of this review.

Surface-Crosslinked Guar Gum-g-Sodium Polyacrylate Superabsorbents: Swelling Characteristics and Mechanics Performance

Guar gum grafted sodium polyacrylate have been prepared via aqueous solution graft polymerization. Furthermore, the polymers were then surface-crosslinked using trimethylolpropane triglycidyl ether (TMPTGE) to improve the properties of swollen hydrogel. Polymerization conditions were systematically optimized to achieve the optimum swelling capacity. FTIR and DSC spectra confirmed that sodium acrylate had been grafted onto guar gum chains. SEM observations showed morphology of the samples. The results confirmed that introducing guar gum into the superabsorbent could improve the swollen hydrogel mechanics performance, including hydrogel strength, resilience and dispersion, although making the water absorbency decreasing slightly. The good mechanics performance will make it feasible in hygiene application.

A new guar gum-based adsorbent for the removal of Hg(II) from its aqueous solutions

Modification of biopolymers by oxidation is an easy process to develop effective adsorbents for the removal of toxic metal ions from their aqueous solutions. In the present study, guar gum (GG) was crosslinked with epichlorohydrin and then oxidized to the polydialdehyde form (GG-clPDA). The latter was converted to a Schiff-base, GG-clCHN(CH2)6NCHGG, by reaction with hexamethylenediamine. Different forms of the modified GG were characterized by SEM, FTIR and XRD and investigated as adsorbents for the removal of Hg(II) ions from their aqueous solutions. The adsorption process was carried out through the variation of time, temperature, pH and initial concentration of Hg(II) ions. GG-clCHN(CH2)6NCHGG was observed to be an efficient adsorbent with a maximum adsorption capacity of 41.13 mg/g. It is reusable up to five cycles at the optimum conditions obtained for the maximum ions uptake. The kinetic data generated fit the Freundlich isotherm and pseudo-second order kinetics.