Nanocomposite super‐swelling hydrogels with nanorod bentonite

Abstract

A modified bentonite (nanorod bentonite) was obtained from conventional bentonite by an ultrasonic treatment. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images indicated that modified bentonite comprised rod-shape morphology without any change in the chemical structure confirmed by Fourier transform infrared (FTIR) spectroscopy and Xray diffraction (XRD) patterns. Novel super-swelling hydrogels with nanocomposite structure were then prepared via solution polymerization of 2-acrylamido-2-methylpropane sulfonic acid (AMPS) and (N-[3-(dimethylamino)propyl] methacrylamide) (DMAPMA) in the presence of the nanobentonite and a crosslinker. The DMAPMA consisted of either intercalant or monomer in the polymerization. The hydrogel products were characterized by FTIR, swelling studies, dynamic mechanical thermal analysis (DMTA), XRD, and rheological measurements. It was proposed that exfoliated and intercalated morphology were obtained at low and high-nanobentonite contents, respectively. DMTA indicated that mechanical properties of the dried gel were improved with raising the clay content. In the water-swollen state, storage modulus was considerably increased in nanocomposites having <8% of modified bentonite, and then it was decreased at the higher clay content due to interfering effect of the clay in polymerization progression.

Recent advances in clay mineral-containing nanocomposite hydrogels

“…It is noteworthy that such an increment is also caused by the CNPs used in the hydrogels. For instance, Darvishi et al 109 and when attapulgite was used for PAA/attapulgite nanocomposite hydrogels. 115 In comparison to attapulgite, kaolinite, and mica, PAM/Na + -montmorillonite nanocomposite hydrogels exhibit a higher swelling rate in distilled water.…”

Synthesis and characterization of chitosan‐graft‐poly(acrylic acid)/nontronite hydrogel composites based on a design of experiments

“…In light of this, many researchers have focused on the introduction of natural polymers [e.g., starch, 4 chitosan (CTS), 5 and arabic gum 6] by grafting synthetic polymers to the biopolymer backbone rendering biodegradable, biocompatible, and/or superabsorbent hydrogels. 9,10 However, it has been shown that the swelling capability, strength, and thermal behavior can be tuned through the addition of organic fillers (e.g., cellulose, 11,12 starch, 13 and chitin 13 nanocrystals) and inorganic fillers (e.g., magnetic nanoparticles, 14 ash, 15 and clays such as montmorillonite, 16 vermiculite, 17 and bentonite 18 ) with nanometric dimensions due to the formation of nanocomposite materials. 9,10 However, it has been shown that the swelling capability, strength, and thermal behavior can be tuned through the addition of organic fillers (e.g., cellulose, 11,12 starch, 13 and chitin 13 nanocrystals) and inorganic fillers (e.g., magnetic nanoparticles, 14 ash, 15 and clays such as montmorillonite, 16 vermiculite, 17 and bentonite 18 ) with nanometric dimensions due to the formation of nanocomposite materials.…”

Poly(2‐hydroxyethyl methacrylate) nanocomposites: From a nonionic gel to pH sensitivity

“…In the past decades, to improve the properties of hydrogels, many efforts have been made [4–8]. Recently, polymer/clay nanocomposites have been studied to improve the properties of hydrogels such as swelling and deswelling properties and mechanical strength [4, 9–11]. Montmorillonite (MMT) [12, 13], kaolin [14], mica [15, 16], attapulgite [17], and halloysite [15] have already been incorporated into the polymer structure.…”