Synthesis of an alginate–poly(sodium acrylate‐co‐acrylamide) superabsorbent hydrogel with low salt sensitivity and high pH sensitivity

Abstract

This article describes the synthesis and swelling behavior of a superabsorbing hydrogel based on sodium alginate (NaAlg) and polyacrylonitrile (PAN). The physical mixture of NaAlg and PAN was hydrolyzed with a solution of NaOH to yield an alginate-poly(sodium acrylate-co-acrylamide) [Alg-poly(NaAA-co-AAm)] superabsorbent hydrogel. A proposed mechanism for hydrogel formation was suggested, and the structure of the product was established with Fourier transform infrared spectroscopy. The effects of reaction variables were systematically optimized to achieve a hydrogel with a swelling capacity as high as possible. Under the optimized conditions concluded, the maximum capacity of swelling in distilled water was 610 g/g. The absorbency of the synthesized hydrogels was also measured in various salt solutions. The swelling ratios decreased with an increase in the ionic strength of the salt solutions. In addition, the swelling capacity was determined in solutions with pHs ranging from 1 to 13. The Algpoly(NaAA-co-AAm) hydrogel exhibited pH responsiveness, so a swelling-deswelling pulsatile behavior was recorded at pHs 2 and 8. This on-off switching behavior made the hydrogel as a good candidate for the controlled delivery of bioactive agents. Finally, the swelling kinetics of the hydrogels with various particle sizes were preliminarily investigated as well.

Recycling of reactive dye using semi‐interpenetrating polymer network from sodium alginate and isopropyl acrylamide

“…NaAlg, a natural ionic hydrophilic linear polysaccharide containing β‐ d ‐mannuronic acid and α‐ l ‐guluronic acid (Scheme ) with OH and COO − groups are commonly used in the synthesis of hydrogels for different applications with improved mechanical properties . The sugar residues in NaAlg can either be arranged in blocks or they can be randomly distributed . Moreover, NaAlg‐based semi‐IPN was shown to be an excellent adsorbent for the removal of colored materials and toxic heavy metal ions from industrial effluent .…”

“…The sugar residues in NaAlg can either be arranged in blocks or they can be randomly distributed . Moreover, NaAlg‐based semi‐IPN was shown to be an excellent adsorbent for the removal of colored materials and toxic heavy metal ions from industrial effluent . Hence, semi‐IPN is viewed as one of the potential adsorbent for recycling of colored materials .…”

“…17 Moreover, NaAlgbased semi-IPN was shown to be an excellent adsorbent for the removal of colored materials and toxic heavy metal ions from industrial effluent. [16][17][18][19] Hence, semi-IPN is viewed as one of the potential adsorbent for recycling of colored materials. 11,18 The present investigation involves the synthesis and evaluation of potential adsorbent to recycle reactive dye from the textile dye effluent.…”

Enhanced swelling and methylene blue adsorption of polyacrylamide‐based superabsorbents using alginate modified montmorillonite

“…Furthermore, there exist only a few reports on the investigation of SAPs incorporated with clay and polysaccharides to improve their dye adsorption properties . It was reported that the organic modification of clay could improve the performance of SAPs/clay composites . Inspired by this, we prepared SAPs/clay composites using polysaccharides modified clay, the reaction was carried out under normal atmospheric conditions which caused brevity and simplicity in industrial processes …”

Alginate graft copolymers and alginate–co-excipient physical mixture in oral drug delivery

“…The pH-sensitive swelling characteristics of graft copolymer render it suitable for use to control drug release as a function of pH. Alginate-poly(sodium acrylate-co-acrylamide) [134] Hydrogel exhibits swelling-deswelling pulsatile behaviour at pH 2 and 8. The swelling of hydrogel decreases with an increase in ionic strength of the surrounding medium.…”