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Superabsorbent hydrogel composed of covalently crosslinked gum arabic with fast swelling dynamics
Author(s) -
Favaro Silvia L.,
de Oliveira Fernando,
Reis Adriano V.,
Guilherme Marcos R.,
Muniz Edvani C.,
Tambourgi Elias B.
Publication year - 2007
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.27140
Subject(s) - swelling , gum arabic , glycidyl methacrylate , acrylamide , materials science , absorption of water , composite material , distilled water , acrylic acid , arabic , chemical engineering , polymer chemistry , chemistry , nuclear chemistry , polymer , chromatography , organic chemistry , monomer , linguistics , philosophy , engineering
Abstract A superabsorbent hydrogel (SH) with fast swelling dynamics and good mechanical stability in the swollen state was prepared. The SH was obtained from chemically modified gum arabic (MGA) with glycidyl methacrylate (GMA), acrylic acid (AAc), and acrylamide (AAm). The water‐transport mechanisms and equilibrium swelling ratio (SR) were the parameters used to describe the water‐absorption profile of SH. A 2 3 factorial design with a central point was built to evaluate the influence of the chemical modification of gum arabic (GA) on the SH sensitivity to water. The main effects of the temperature and amount of GMA and the interaction effect of the temperature and amount of GMA on the SR responses were statistically significant. It was demonstrated that the amount of GMA had a more prominent effect on gel swelling. Lower elastic modulus values for the SH were found when a decreased amount of GMA was used (0.05 g), which produced an SH with a high SR capacity. The SH matrix consisting of 3.0 g of AAc, 0.5 g of AAm, and 0.5 g of MGA was more suitable to absorb a large amount of water (SR = 503.17 ± 22.65 within 60 min of water immersion) without its mechanical stability being affected. Better GA modifying conditions to produce such an SH were as follows: 60°C for the temperature, 24 h for the time of MGA, and 0.05 g for the amount of GMA. It exhibited a diffusional exponent higher than 0.89, which corresponded to the supercase II type of penetrating transport mechanism, indicating that its water‐absorption mechanism exclusively depended on the macromolecular relaxation of the polymer chains. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008