Synthesis, Characterization, and Swelling Properties of a New Highly Absorbent Hydrogel Based on Carboxymethyl Guar Gum Reinforced with Bentonite and Silica Particles for Disposable Hygiene Products.

Superabsorbent polymers derived from petroleum have been widely used as the primary component of high-water-absorption disposable sanitary products. However, environmental concerns as well as unstable market prices influence the quality of disposable hygiene products. The development of superabsorbent polymers from natural, non-petroleum-derived materials has become more predominant. In the present study, two borax-cross-linked carboxymethyl guar-based superabsorbents with bentonite (CMG-Bt) and fumed silica particle reinforcement (CMG-Bt-Si) were synthesized. The materials have been fully characterized by various techniques. The swelling behavior was studied through free swelling capacity (FSC) and centrifuge retention capacity (CRC). The swelling kinetics and urea absorption capacity were further analyzed. The effects of the cross-linking ratio, mineral clay, silica particles, and pH of the liquids on the swelling properties of the superabsorbents have been studied. The incorporation of silica particles demonstrated a positive effect on water uptake reaching 78.63 and 41.09 g/g of FSC and CRC, respectively, at an optimum pH of 6.8. The optimum swelling kinetics were attributed to CMG-Bt-Si of 5 wt % silica particle content, indicating a velocity parameter (ζ) of 41 s in saline solution. Finally, the highest swelling values were obtained at 10, 10, and 5 wt % for the cross-linking ratio, bentonite content, and silica particle content, respectively; in addition, the absorption of urea by the CMG-Bt-Si material was also confirmed.

A Novel Superabsorbent Polymer from Crosslinked Carboxymethyl Tragacanth Gum with Glutaraldehyde: Synthesis, Characterization, and Swelling Properties.

Nowadays, current global environmental problems include measures to eliminate or reduce the negative impact of chemicals from petroleum sources and, therefore, the use of materials from natural resources is increasingly recommended. In this context, natural-based superabsorbent polymers derived from polypeptides and polysaccharides have undergone chemical and biochemical modifications to improve their ability to absorb and retain large amounts of liquids. In the present paper, a new process has been used to overcome the side effects of radical polymerization in the manufacture of conventional polyacrylate superabsorbents (SAPs). Tragacanth gum (TG) was selected to prepare a new superabsorbent material (CMTG-GA) based on carboxymethyl tragacanth (CMTG) crosslinked with glutaraldehyde (GA). The characterization of the polymer was carried out by FTIR, TGA, XRD, and SEM. The effect of the amount of crosslinking agent and the pH on the water absorption capacity was also examined. Subsequently, swelling studies were performed using free swelling capacity (FSC) and centrifuge retention capacity (CRC) techniques in distilled water, tap water, and saline solution. The results showed that the CRC of the new material is not less than 42.1 g/g, which was observed for a ratio of 20% by weight of GA to CMTG. Likewise, the maximum absorption results were 43.9 and 32.14 g/g, respectively, for FSC and CRC at pH 8.0. In addition, a comparison of the swelling capacities of the synthesized product with a commercial SAP extracted from a baby diaper, well known in the Moroccan market, showed that the performances were very similar.