Development of Novel Superabsorbent Hybrid Hydrogels by E-Beam Crosslinking

Abstract

In this study, several superabsorbent hybrid hydrogel compositions prepared from xanthan gum (XG)/sodium carboxymethylcellulose (CMC)/graphene oxide (GO) were synthesized by e-beam radiation crosslinking. We studied and evaluated the effects of GO content from the chemical structure of the hydrogels according to: sol-gel analysis, swelling degree, diffusion of water, ATR-FTIR spectroscopy, network structure, and dynamic mechanical analysis. The gel fraction and swelling properties of the prepared hydrogels depended on the polymer compositions and the absorbed dose. The hybrid XGCMCGO hydrogels showed superabsorbent capacity and reached equilibrium in less than 6 h. In particular, the XGCMCGO (70:30) hydrogel reached the highest swelling degree of about 6000%, at an irradiation dose of 15 kGy. The magnitude of the elastic (G′) and viscous (G″) moduli were strongly dependent on the absorbed dose. When the degree of crosslinking was higher, the G′ parameter was found to exceed 1000 Pa. In the case of the XGCMCGO (80:20) hydrogel compositions, the Mc and ξ parameters decreased with the absorbed dose, while crosslinking density increased, which demonstrated that we obtained a superabsorbent hydrogel with a permanent structure.

NaAlg-g-AA Hydrogels: Candidates in Sustainable Agriculture Applications

“…The hydrogel structure and the cross-linking degree are usually dependent on the irradiation dose [ 31 ]. If natural polymers are added to the monomeric solutions, unstable structures and insufficient cross-linking degrees can be obtained by e-beam irradiation [ 32 ].…”

“…According to the literature [ 54 , 59 ], n values can be as follows: (i) n < 0.45–0.5 for Fickian diffusion or Case I, where the rate of solvent diffusion is much lower compared to the macromolecular chain relaxation of the polymer [ 32 ]; (ii) 0.45–0.5 < n < 1.0 for non-Fickian diffusion or anomalous (in which the diffusion of the solvent into the hydrogel structure is fast compared to the relaxation rate of the macromolecular chain of the polymer [ 32 ]; (iii) n = 1.0 for zero order or Case II, where the diffusion process is much faster than the relaxation process [ 32 ]; and (iv) n > 1.0 for super Case II type of penetrating mechanism. The anomalous case is a summation of Fickian diffusion (Case I) and non-Fickian diffusion (Case II) [ 54 , 60 ].…”

Kappa-carrageenan and sodium alginate-based pH-responsive hydrogels for controlled release of methotrexate

“…It is clear from the data that solvent molecules diffused into hydrogel matrix. As the value of n for hydrogels is in accordance with 0.5 < n < 1 that indicated anomalous non-Fickian diffusion was followed by water molecules [ 47 ].…”

3D Porous Collagen Matrices—A Reservoir for In Vitro Simultaneous Release of Tannic Acid and Chlorhexidine

“…On the other hand, TA , as a specific representative of natural tannins, may interact with collagen not only by hydrogen bonding [ 17 , 18 ], but also hydrophobically [ 18 , 19 , 20 ], with the formation of tannin–protein complexes [ 20 ]. By choosing TA as a crosslinking agent for collagen hydrogels or collagen-based dry matrices, the potential cytotoxicity produced by the classical chemical crosslinkers [ 21 ] can thus be avoided, even though there is also the approach of obtaining real hydrogels covalently crosslinked under the action of ionizing radiation (γ rays, accelerated electron beams) in the absence of any crosslinking molecules when it comes to the synthesis of collagen-based hydrogels [ 22 , 23 , 24 ], or, generally, of other types of polymer/biopolymer hydrogels [ 25 , 26 ]. Starting from the general crosslinking ability reported in building up 3D polymeric networks [ 27 ], TA has proved to be a very promising partner in TA -crosslinked collagen scaffolds intended for many biomedical purposes [ 27 , 28 , 29 , 30 , 31 , 32 , 33 ], and, very recently, even in attempting to synthesize a solid catalyst consisting of collagen fibers loaded with TA , Fe 3+ , and peroxymonosulfate, with excellent properties of adsorption towards rhodamine B (via π–π interactions between TA and the organic dye) and chemical affinity to decompose it (by facilitating redox cycle Fe 3+ -Fe 2+ under the reducing activity of TA to finally promote production of sulfate radicals from peroxymonosulfate effective in dye decay), and, eventually, dedicated to treating the industrial wastewater polluted with aromatic-type organic dyes [ 33 ].…”