Abstract

Mohammad Sadeghi¹ and Mojgan Yarahmadi²

This article describes the synthesis of a superabsorbing hydrogel based on sodium alginate (NaAlg) and polyacrylonitrile (PAN). The physical mixture of Alg and PAN was hydrolyzed by NaOH solution to yield Alg-poly(sodium acrylate-co-acrylamide) superabsorbent hydrogel. The nitrile groups of PAN were completely converted to a mixture of hydrophilic carboxamide and carboxylate groups during alkaline hydrolysis followed by in situ crosslinking of the PAN chains by the alkoxide ions of sodium alginate. A proposed mechanism for hydrogel formation was suggested and the structure of the product was established using FTIR spectroscopy. The effect of reaction variables such as concentration of NaOH, hydrolysis time, hydrolysis temperature and PAN/Alg wight ratio were systematically optimized to achieve a hydrogel with swelling capacity as high as possible. Under the optimized conditions concluded, maximum capacity of swelling in distilled water was found to be 518 g/g. .

sodium alginate; polyacrylonitrile; hydrogel; superabsorbent; swelling behavior

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