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Modified carrageenan. 2. Hydrolyzed crosslinked κ -carrageenan-g-PAAm as a novel smart superabsorbent hydrogel with low salt sensitivity

Hosseinzadeh, H ; Sharif University of Technology | 2004

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  1. Type of Document: Article
  2. DOI: 10.1163/1568562042459715
  3. Publisher: 2004
  4. Abstract:
  5. A novel pH-responsive superabsorbing hydrogel based on κ-carrageenan (κC) was prepared through polyacrylamide crosslinking grafting followed by alkaline hydrolysis. The hydrogel structure was confirmed using FT-IR spectroscopy. The hydrolysis conditions were systematically optimized to obtain a hydrogel with maximum swelling capacity. Thus, the reaction variables, including the hydrolysis time and temperature, concentration of sodium hydroxide, amount of hydrogel hydrolyzed and post-neutralization pH, were optimized. The swelling measurements of the hydrogels were conducted in 0.15 M aqueous solutions of LiCl, NaCl, KCl, CaCl2 and AlCl3. As observed for the hydrolyzed hydrogel (H-carragPAM), it was found that a 'charge screening' action of small cations and carboxylate anions affected the swelling in univalent salt solutions. In the case of the non-hydrolyzed hydrogel (carragPAM), however, a converse trend was observed. As a result, carragPAM and H-carragPAM superabsorbent hydrogels showed a maximum swelling of 45 and 135 g/g in LiCl and KCl solutions, respectively. Due to the high swelling capacity in salt solutions, the hydrogels may be referred to as anti-salt superabsrbents. The swelling of superabsorbing hydrogels was examined in buffer solutions with pH values ranging between 1 and 13. The H-carragPAM hydrogel exhibited a pH-responsie character so that a swelling-deswelling pulsatile behavior was recorded at pH 4 and 9. The swelling kinetics of H-carragPAM were preliminary investigated. © VSP 2004
  6. Keywords:
  7. Carrageenan ; Graft polymerization ; Hydrogel ; PH-sensitive ; Superabsorbent ; Swelling
  8. Source: Journal of Biomaterials Science, Polymer Edition ; Volume 15, Issue 12 , 2004 , Pages 1499-1511 ; 09205063 (ISSN)
  9. URL: https://www.tandfonline.com/doi/abs/10.1163/1568562042459715