Chitosan modified MMT‐poly(AMPS) nanocomposite hydrogel: Heating effect on swelling and rheological behavior

Vulnerability of hydrogels against thermal circumstances may be substantially eliminated via incorporating nanoclay to prepare nanocomposite hydrogels. In this research, chitosan‐intercalated montmorillonite (ChitoMMT) was used as a bionanoclay to yield novel nanocomposite hydrogels based on 2‐acrylamido‐2‐methylpropanesulfonic acid. The bionanoclay is suitable especially for preparing biomaterials used in biomedical, food, and pharmaceutical applications, unlike conventional commercial nanoclays (alkyl ammonium‐intercalated MMT) which are not appropriate for bio‐applications due to toxicity of the intercalant particularly where the clay content is high. Two different crosslinkers (i.e., methylene bisacrylamide, and polyethyleneglycol dimethacrylate) were employed to synthesize the nanocomposites. The variations in swelling, rheological and thermal properties of the hydrogels were essentially attributed to thermally induced crosslink cleavage/formation depending upon the crosslinker nature. The nanocomposites comprised superior thermal properties in comparison with the clay‐free hydrogel counterpart. They can preserve substantially their swelling ability for longer heating periods. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effect of intercalated hydrotalcite on swelling and mechanical behavior for poly(acrylic acid‐co‐N‐isopropylacrylamide)/hydrotalcite nanocomposite hydrogels

A series of nanocomposite hydrogels were prepared from acrylic acid (AA), N‐isopropylacrylamide (NIPAAm), and intercalated hydrotalcite (IHT) by photopolymerization. The influence of the intercalating content of 2‐acrylamido‐2‐methyl propane sulfonic acid (AMPS) in HT on the swelling and mechanical properties for poly(AA‐co‐NIPAAm)/IHT nanocomposite hydrogels was investigated. The results showed that the higher the content of the AMPS‐HT was, the higher the swelling ratio of the gels and the higher the content of the intercalating agent was, the lower swelling ratio. It was also demonstrated that the swelling ratio of the gel was not affected by the counterion in HT. The gel strength and crosslinking density were not enhanced by adding AMPS‐HT into the gel composition, but the maximum effective crosslink density and shear modulus of the nanocomposite hydrogels were increased with an increase of the content of the intercalating agent in HT. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1572–1580, 2005     

Antipolyelectrolyte superabsorbing nanocomposites: Synthesis and properties

Novel polyampholytic superabsorbing nanocomposites based on the zwitterionic sulfobetaine monomer [3‐(methacrylamido)propyl)]dimethyl(3‐sulfopropyl)ammonium hydroxide were synthesized through in situ polymerization in aqueous solution with different contents of an organo‐modified clay (OMMT, Cloisite 30B). Structural and thermomechanical properties of hydrogels were characterized by FT‐IR, XRD, and DMTA, respectively. Swollen gel strength of hydrogels was determined by a rheological method. Storage modulus of the hydrogels was considerably improved in comparison with its the clay‐free counterpart. The nanocomposite hydrogel containing 15% OMMT possessed the highest gel strength. The glass transition temperature was increased from 58.4 to 67.0°C for the clay‐free and nanocomposite hydrogel containing 8% OMMT, respectively. The swelling behavior of the hydrogel in various salt solutions was investigated. Antipolyelectrolyte behavior was observed with enhancement of concentration of mono‐ and multivalent salts. Swelling in the various pH media was nearly pH‐independent over a wide range of pH. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Undesirable effects of heating on hydrogels

Heating is the most conventional drying method for removing water from as‐synthesized hydrogels in laboratory and industry. In this article, the effects of the heating temperature (60–200°C) and time (10 min–24 h) on swelling properties of highly absorbent hydrogels based on 2‐acrylamido‐2‐methylpropane sulfonic acid (AMPS), acrylic acid (AA), potassium acrylate (KA), and acrylamide (AM) were studied. Crosslinkers methylene bisacrylamide (MBA) and poly(ethyleneglycol) dimethacrylate (PEGDMA) were used in the syntheses. Depending on the hydrogel structural composition and its drying temperature and time, the swelling capacities were extremely changed. Generally, AA‐, KA‐, and AM‐based hydrogels showed more hydrolytic‐thermal stability than the corresponding AMPS‐based hydrogels. MBA‐crosslinked hydrogels generally exhibited higher vulnerability against heating. Swelling of PEGDMA‐crosslinked poly(AM‐KA‐AA) hydrogel was greatly increased after heating, whereas its analogousAM‐free sample exhibited huge loss of swelling. PEGDMA‐crosslinked poly(AMPS) samples also exhibited swelling reduction after drying. Rheological studies showed that the storage modulus was highly reduced (～ 5200 Pa) after heating of MBA‐crosslinked poly(AMPS) hydrogels, which reconfirmed the crosslink cleavage. Mechanistic discussions were proposed for the thermal‐induced swelling changes. It was concluded that the chemical nature of both crosslinker and monomer must be taken into consideration to choose the temperature and time of the hydrogel drying. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

A new composite sorbent for water and dye uptake: Highly swollen acrylamide/2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid/clay hydrogels crosslinked by 1,4‐butanediol dimethacrylate

A novel type of highly swollen hydrogels based on acrylamide (AAm) with 2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid (AMPS) and clay such as bentonite (Bent) crosslinked by 1,4‐butanediol dimethacrylate (BDMA) was prepared by free radical solution polymerization in aqueous media. Water uptake and dye sorption properties of polyelectrolyte AAm/AMPS hydrogels and AAm/AMPS/Bent composite hydrogels were investigated as a function of composition to find materials with swelling and sorption properties. FTIR analyses were made. Swelling experiments were performed in water and dye solution at 25°C, gravimetrically. Highly swollen AAm/AMPS and AAm/AMPS/Bent hydrogels were used in experiments on sorption of water‐soluble monovalent cationic dye such as Lauths violet “LV, (Thionin).” Swelling of AAm/AMPS hydrogels was increased up to 1,920–9,222% in water and 867–4,644% in LV solutions, while AAm hydrogels swelled 905% in water and swelling of AAm/AMPS/Bent hydrogels was increased up to 2,756–10,422% in water and 1,200–3,332% in LV solutions, while AAm/Bent hydrogels swelled 849% in water. Some swelling kinetic and diffusional parameters were found. Water and LV diffusion into hydrogels was found to be non‐Fickian in character. For sorption of cationic dye, LV into AAm/AMPS and AAm/AMPS/Bent hydrogel was studied by batch sorption technique at 25°C. The amount of the dye sorbed per unit mass removal effiency and partition coefficient of the hydrogels was investigated. The influence of AMPS content in the hydrogels to sorption was examined. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Swelling properties of CMC‐g‐poly (AAm‐co‐AMPS) superabsorbent hydrogel

A series of biopolymer‐based superabsorbent hydrogels based on carboxymethyl cellulose has been prepared by free‐radical graft copolymerization of acrylamide and 2‐acrylamido‐2‐methylpropan sulfonic acid (AMPS) in aqueous solution using methylenebisacrylamide as a crosslinking agent and ammonium persulfate as an initiator. The effect of variables on the swelling capacity such as: acrylamide/AMPS weight ratio, reaction temperature, and concentration of the initiator and crosslinker were systematically optimized. The results indicated that with increasing the amount of AMPS, the swelling capacity is increased. FT‐IR spectroscopy and scanning electron microscope analysis were used to confirm the hydrogel structure. Swelling measurements of the synthesized hydrogels in different salt solutions indicated considerable swelling capacity. The absorbency under load of the superabsorbent hydrogels was determined by using an absorbency under load tester at various applied pressures. A preliminary swelling and deswelling behaviors of the hydrogels were also studied. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Thermo-hydrolytic stability of swelling capacity of superabsorbing composite hydrogels based on AMPS and acrylamide

N,N′-Methylenebisacrylamide (MBA) is a conventional crosslinker most often used to produce hydrogels. We have previously shown that MBA-crosslinks were thermo-hydrolytically cleaved upon heating during oven-drying, particularly in hydrogels based on 2-acrylamido-2-methylpropane sulfonic acid (AMPS). The present paper deals with the effect of comonomer acrylamide (AM, ranged 0–100%) and an organomodified clay on swelling stability of MBA-crosslinked poly(AMPS–AM) superabsorbing composite hydrogels. It was found that either AM or the organoclay had constructive effects on thermo-hydrolytic stability of the network through delaying or stopping the undesirable swelling changes originated from the crosslink cleavage, de-crosslinking. The incorporated organomodified clay, however, exhibited fewer stabilizing effect rather than AM, when AM content was higher than 15%. The swelling of hydrogels was turned out to be stable during heating even at high temperature (200 °C) when they composed at least 15% AM. Based on rheometrical studies, swollen gel strength of heated composite hydrogel was typically shown to be significantly higher than that of the clay-free counterpart.     

HES-HEMA nanocomposite polymer hydrogels: swelling behavior and characterization

Organophilic sodium montmorillonite (Na-MMT) and Laponite-RD clays were incorporated into photopolymerizable hydroxyethyl starch (HES) modified with 2-hydroxyethyl methacrylate (HEMA). Swelling, mechanical properties and thermal stability of obtained crosslinked nanocomposite polymers were evaluated. A camphorquinone-amine system was used as photoinitiating system in visible light. The interaction between nano-sized filler particles and polymer hydrogel was evaluated by FT-IR spectroscopy and the platelet distribution was investigated by SEM. An increased thermal stability of nanocomposite polymers upon addition of clay was observed by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) indicating interaction between the clay platelets and the polymer chains. The crosslinking density for HES-HEMA/MMT nanocomposite hydrogels as investigated by swelling measurements increases with increasing the organo-clay content. The mechanical properties of virgin hydrogels were improved by the introduction of organo-clay as evidenced by oscillation rheology measurements. Whereas, the increase in crosslink density and storage modulus with clay content for laponite was found to be increasing for all concentrations investigated, for MMT there is an optimum content of ca. 1.5 wt%.     

Solvent-, ion- and pH-specific swelling of poly(2-acrylamido-2-methylpropane sulfonic acid) superabsorbing gels

Homopolymer hydrogel of 2-acrylamido-2-methylpropane sulfonic acid (AMPS) and its nanocomposite counterpart were prepared to study their swelling properties. The hydrogels showed ability to absorb and retain electrolytes as well as binary mixtures of water and organic solvents (i.e., methanol, ethanol, acetone, ethylene glycol (EG), polyethylene glycol, N-methyl-2-pyrrolidone (NMP), and dimethylsulfoxide (DMSO). The nanocomposite gel exhibited lower swelling in all solvent compositions in comparison with non-composite gel. Unlike conventional acrylic acid-based hydrogels, the poly(AMPS) gels showed superabsorbing capacity in pure ethanol, methanol, EG, DMSO and NMP. Meanwhile, swelling capacity of poly(AMPS) hydrogel in DMSO-water mixtures was surprisingly found to be even higher than that in water. This extraordinary superswelling behavior was explained based on the interactions involved in solvation as well as the solubility parameters. The gels showed pH-independent superabsorbency in a wide range of pH (3–11). Saline-induced swelling transitions were also investigated and the ionic interactions were confirmed by FTIR spectroscopy.     

Swelling behavior and structural characteristics of polyvinyl alcohol/montmorillonite nanocomposite hydrogels

A series of nanocomposite hydrogels based on polyvinyl alcohol containing 0–10 wt % of the organically modified montmorillonite clay were prepared by freezing‐thawing cyclic method. The morphology of the nanocomposite hydrogels was observed by the scanning electron microscopy technique. The structural properties were determined by measuring the network mesh size, crosslinking density, and average molecular weight of polymer chains between crosslinks. The swelling behavior and the effect of swelling medium temperature on the swelling kinetics and characteristics of the nanocomposite hydrogels were also investigated. The results showed that two structural characteristics i.e., network mesh size and average molecular weight of polymer chains between crosslinks have inverse dependence on the clay loading level in the nanocomposite hydrogel, while crosslinking density shows completely direct dependence. Swelling measurements demonstrated a linear relation between the degree of swelling and the square root of immersion time at all swelling medium temperatures. The results indicated that the swelling characteristics of the nanocomposite hydrogels including the equilibrium degree of weight and volume swelling and the equilibrium water content were decreased by increasing the quantity of the clay incorporated into the hydrogel as well as by decreasing the temperature of swelling medium. While, the time required to reach to the equilibrium condition, as another swelling characteristic of the hydrogels, exhibited a completely opposite behavior. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.     

Rheological properties of thermoresponsive nanocomposite hydrogels

Highly elastic and robust nanocomposite hydrogels based on N‐isopropylacrylamide (NIPAM) and cationic (3‐acrylamidopropyl) trimethylammonium chloride (AMPTMA) were synthesized by photopolymerization. Nanoscopic clay, laponite XLS, was added in the gels during the synthesis. The effect of a hydrophobic salt, lithium bis(trifluoromethane) sulfonimide (LiNTf₂), and clay content on the viscoelastic properties, swelling ratio, and stiffness of the nanocomposite hydrogels were investigated as a function of temperature. Synthetic clay served as a multifunctional cross‐linker, producing hydrogels with enhanced elastic properties. Anionic NTf₂ binds to the cationic comonomer units and significantly affected the viscoelasticity and thermal properties. DSC measurements showed that the volume phase transition temperature and its enthalpy changed with the clay content and with introducing the cationic comonomer (AMPTMA) in the PNIPAM network. With the addition of either laponite XLS or the comonomer and 5 mM solution of LiNTf₂, a fourfold and fivefold increase in elastic modulus was obtained, respectively, compared to that of the homopolymer PNIPAM hydrogel. With increasing the temperature from 20 to 45°C for the copolymer gel with 10% AMPTMA in 5 mM LiNTf₂, the elastic modulus grew 15 times larger. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43123.     

Swelling behavior of novel protein‐based superabsorbent nanocomposite

A novel superabsorbent nanocomposite based on hydrolyzed collagen was synthesized by simultaneously graft copolymerization of 2‐acrylamido‐2‐methylpropane sulfonic acid (AMPS) and acrylamide (AAm). Sodium montmorilonite (Na‐MMt) was used as clay. Methylenebisacrylamide (MBA) and ammonium persulfate (APS) were used as crosslinker and initiator, respectively. The effect of reaction variables such as nanoclay content, MBA and APS concentrations as well as the AMPS/AAm weight ratio on the water absorbency of nanocomposites was investigated. Although the water absorbency was decreased by increasing of MBA concentration, an optimum swelling capacity was achieved for clay, APS, and AMPS/AAm variables. The structure of nanocomposite was identified using FTIR spectroscopy, XRD patterns, and scanning electron microscopy graphs. The effect of swelling media comprising various dissolved salts and different pHs was studied. Also, water retention capacity was studied, and the results showed that inclusion of Na‐MMt nanoclay causes an increase in water retention under heating. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis and evaluation of swelling kinetics of electric field responsive poly(vinyl alcohol)‐g‐polyacrylic acid/OMNT nanocomposite hydrogels

Novel electro‐responsive nanocomposite hydrogels were prepared by the radical graft polymerization reaction of partially neutralized acrylic acid on poly(vinyl alcohol) and organically modified MMT nanoclay (OMMT) using glutaraldehyde as a crosslinker and potassium initiator. The structures of the hydrogels were confirmed by using Fourier transform infrared, X‐ray diffraction, and scanning electron microscopy study. The nanocomposite hydrogels were characterized by evaluating such molecular weight between crosslinks, (Mc) crosslinking density (ρ), and mesh size (ξ). The effects of various parameters on the swelling behavior of the hydrogels were studied. The thermogravimetric analysis indicated that introduction of clay resulted in an increase in thermal stability. Finally, the electric stimuli responsive measurement indicates the bending of hydrogel toward the cathode in an aqueous solution of NaCl. POLYM. COMPOS., 36:34–41, 2015. © 2014 Society of Plastics Engineers     

Rheological properties of poly(ethylene glycol)/poly(N‐isopropylacrylamide‐co‐2‐acrylamido‐2‐methylpropanesulphonic acid) semi‐interpenetrating networks

For the increasing demands of multifunctional materials in applications such as drug delivery system, a pH‐ and temperature‐responsive polyelectrolyte copolymer gel system was studied using rheometry. Rheological properties, determined by plate–plate rheometry in oscillatory shear, of hydrogels formed by free radical initiated copolymerization of N‐isopropylacrylamide (NIPA) and 2‐acrylamido‐2‐methylpropanesulphonic acid (AMPS) in the presence of methylene bisacrylamide (MBAA) as crosslinker are compared with the properties of semi‐interpenetrating network (SIPN) polyelectrolyte gels made by incorporation of poly(ethylene glycol) with molar mass 6000 g mol^?1 (PEG6000). Based on our systematic studies for this PEG/SIPN system, the effects of initiator and crosslinker concentration, relative proportions of comonomer units in the main chains, PEG6000 content and temperature on viscoelastic properties, unusual high storage moduli at small strain for the SIPN were discussed. The SIPN gel with characteristics of PEG molecules as well as pH and temperature responsiveness from AMPS and NIPA units has potential application in drug delivery system design. Ice‐like rheological behavior of the PEG/AMPS‐NIPA SIPN gels at low temperature was first time reported and water remains homogeneous without phase separation in PEG/AMPS‐NIPA SIPN hydrogels at low temperature may be considered as an ideal candidate for water storage material. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Behaviors of polyelectrolyte AAm/AMPS/bentonite composite hydrogels in uptake of uranyl ions from aqueous solutions

Uranyl ion (UO₂²⁺) sorption properties of polyelectrolyte composite hydrogels made by the polymerization of acrylamide (AAm) with 2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid (AMPS) and clay such as bentonite (Bent) were investigated as a function of composition to find materials with swelling and uranyl ion sorption properties. Highly swollen AAm/AMPS hydrogels and AAm/AMPS/Bent composite hydrogels were prepared by free radical solution polymerization in aqueous solutions of AAm with AMPS as co‐monomer and two multifunctional crosslinkers such as ethylene glycol dimethacrylate (EGDMA) and 1,4 butanediol dimethacrylate (BDMA). Swelling experiments were performed in water at 25°C, gravimetrically. The influence of AMPS content in hydrogels was examined. Uranyl ion adsorption from aqueous solutions was studied by batch sorption technique at 25°C. The effect of uranyl ion concentration and mass of AMPS on the uranyl ion adsorption were examined. Finally, adsorption capacity (the amount of sorbed uranyl ion per gram of dry hydrogel) (q) was calculated to be 0.67 × 10⁻³–2.11 × 10⁻³ mol uranyl ion per gram for the hydrogels. Removal effiency of uranyl ions (RE%) was changed range 9.05–29.92%. The values of partition ratio (K_d) of uranyl ions was calculated to be 0.10–0.43 for AAm/AMPS hydrogels and AAm/AMPS/Bent composite hydrogels, respectively. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers     

Preparation of tailor‐made polystyrene nanocomposite with mixed clay‐anchored and free chains via atom transfer radical polymerization

Tailor‐made polystyrene nanocomposite with mixed free and clay‐attached polystyrene chains was synthesized using atom transfer radical polymerization. Vinylbenzyl trimethylammonium chloride having a double bond, which could be incorporated into polystyrene chains by a grafting through process, was used as a nanoclay modifier. Conversion and molecular weight evaluation was carried out using gas chromatography and gel permeation chromatography, respectively. The thermogravimetric analysis results confirmed the elevated thermal stability of the nanocomposites in comparison with the neat polystyrene sample. Additionally, the T_g increases by clay loading was confirmed by differential scanning calorimetry (DSC). The difference in the degradation temperature of C? Br bond in attached and free polystyrene chains was well revealed in DSC thermograms. Finally, a lower clay loading resulted in an exfoliated structure as proved by X‐ray diffraction and transmission electron microscopy results. © 2010 American Institute of Chemical Engineers AIChE J, 2011     

Harmless hydrogels based on PVA/Na+‐MMT nanocomposites for biomedical applications: Fabrication and characterization

A series of nanocomposite hydrogels were prepared by a freeze‐thaw process, using polyvinyl alcohol (PVA) as polymer matrix and 0–10 wt% of hydrophilic natural Na‐montmorillonite (Na⁺‐MMT), free from any modification, as composite aggregates. The effect of nanoclay content and the sonication process on the nanocomposite microstructure and morphology as well as its properties (physical, mechanical, and thermal) were investigated. The microstructure and morphology were investigated by Fourier transform infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, atomic force microscopy, and X‐ray diffraction technique. The thermal stability and mechanical properties of nanocomposite hydrogels were examined using thermogravimetric analysis, differential scanning calorimetry, dynamic mechanical analysis; moreover hardness and water vapor transmission rate measurements. It was concluded that the microstructure, morphology, physical (thermal) and mechanical properties of nanocomposite hydrogels have been modified followed by addition of nanoclay aggregates. The results showed that Na⁺‐MMT may act as a co‐crosslinker. Based on the results obtained, the nanocomposite hydrogel PVA/Na⁺‐MMT synthesized by a freeze‐thaw process, appeared to be a good candidate for biomedical applications. POLYM. COMPOS., 38:1135–1143, 2017. © 2015 Society of Plastics Engineers     

Structural effects of type of intercalant in poly (4‐vinylpyridine) nanocomposites: compatible homopolymer or block copolymer

4‐vinylpyridine monomer was mixed with organophilic montmorillonite (MMT) clay and polymerized in the presence of free‐radical initiator. MMT clay was rendered organophilic by means of ion‐exchanging sodium cations for low‐molecular‐weight quaternized poly(4‐vinylpyridine) (P4VP) homopolymer and diblock copolymers of styrene and quaternized 4‐vinylpyridine (SVP) with different sequence lengths. The swelling behaviour of the MMT clay was studied by X‐ray diffraction (XRD). After the cation exchange, the resulting organophilic clays showed an expansion of interlayer distance indicating the nanoscale ordering of intercalant polymer and MMT layers. The nanocomposite materials, when moulded, exhibited improved thermal stability and dynamic mechanical properties compared with neat P4VP. The composite, having longer ionic segments in its organophilic MMT, showed exfoliated nanocomposite structure as well as higher stiffness and damping properties at higher temperatures even for MMT loading as low as 2 wt%. Copyright © 2006 Society of Chemical Industry     

Preparation of polystyrene–clay nanocomposites via dispersion polymerization using oligomeric styrene‐montmorillonite as stabilizer

This study describes the preparation of polystyrene–clay nanocomposite (PS‐nanocomposite) colloidal particles via free‐radical polymerization in dispersion. Montmorillonite clay (MMT) was pre‐modified using different concentrations of cationic styrene oligomeric (‘PS‐cationic’), and the subsequent modified PS‐MMT was used as stabilizer in the dispersion polymerization of styrene. The main objective of this study was to use the clay platelets as fillers to improve the thermal and mechanical properties of the final PS‐nanocomposites and as steric stabilizers in dispersion polymerization after modification with PS‐cationic. The correlation between the degree of clay modification and the morphology of the colloidal PS particles was investigated. The clay platelets were found to be encapsulated inside PS latex only when the clay surface was rendered highly hydrophobic, and stable polymer latex was obtained. The morphology of PS‐nanocomposite material (after film formation) was found to range from partially exfoliated to intercalated structure depending on the percentage of PS‐MMT loading. The impact of the modified clay loading on the monomer conversion, the polymer molecular weight, the thermal stability and the thermomechanical properties of the final PS‐nanocomposites was determined. Copyright © 2012 Society of Chemical Industry     

Removal of hazardous by radiation‐synthesized copolymer hydrogels based on 2‐acrylamido‐2‐methylpropanesulfonic acid and 2‐dimethyaminoethyl methacrylate monomers

Superabsorbent copolymer hydrogels were prepared by gamma irradiation of aqueous solutions of 2‐acrylamido‐2‐methylpropanesulfonic acid (AMPS) and 2‐dimethyaminoethyl methacrylate (DEMA) monomers mixtures. The thermal stability of hydrogels was evaluated by thermogravimetric analysis. The ability to adsorb Cu²⁺ ions and dyes by the prepared hydrogels from aqueous solutions was investigated. The swelling study, in water, showed that the hydrogels based on pure AMPS monomer and AMPS/DEMA copolymers reached the equilibrium state after 6 h. However, the hydrogel based on pure AMPS monomer showed higher swelling than the copolymer hydrogels based on AMPS/DEMA. It was found that the copolymer hydrogels based on different compositions showed affinity to absorb Cu²⁺ metal ions as well as basic and acid dyes; however, this affinity was found to decrease with increasing the ratio of DEMA in the initial feeding solutions. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers