Synthetic polymeric absorbent for dye based on chemically crosslinked acrylamide/mesaconic acid hydrogels

Adsorption properties of copolymers of acrylamide and mesaconic acid (CAME) in aqueous Basic Blue 12 (Nile blue chloride) solution have been investigated. Chemically crosslinked CAME hydrogels with various compositions were prepared from ternary mixtures of acrylamide (A), mesaconic(ME) acid, and water by free radical polymerization in aqueous solution, using a multifunctional crosslinker such as ethylene glycol dimethacrylate (EGDMA). Dynamic swelling tests in water was applied to the hydrogels. Weight swelling ratio (S) values have been calculated. Sorption of Basic Blue 12 (BB 12) onto CAME hydrogels was studied by batch sorption technique at 25°C. In the experiments of the sorption, L type sorption in the Giles classification system was found. Some binding parameters such as initial binding constant (K_i), equilibrium constant (K), monolayer coverage (n), site‐size (u), and maximum fractional occupancy (Ô) for CAME hydrogels‐BB 12 binding system were calculated by using Klotz, Scatchard, and Langmuir linearization methods. Finally, the amount of sorbed BB 12 per gram of dry hydrogel (q) was calculated to be 2.28 × 10^?6–7.91× 10^?6 mol BB 12 per gram for hydrogels. Sorption % was changed range 16.09–58.86%. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 405–413, 2006     

Controlled release of testosterone propionate based on poly N-vinyl pyrrolidone/2-acrylamido-2-methyl-1-propanesulfonic acid hydrogels prepared by ionizing radiation

The mechanical properties of SAN/PB-g-SAN blends of different compositions under uniaxial tensile tests were studied. Matrix ligament thickness (MLT) concept was employed to correlate microscopic deformations with macroscopic mechanical response. It was found that, the experimental values of the blends moduli are in a good agreement with the theoretical values obtained from Takayanagi and mixture rules in parallel models. The MLTs in which transition from brittle-to-ductile and from ductile-to-rubbery occur were determined according to interparticle distance model. Fractography studies of the samples with MLT values greater than brittle to ductile transition showed that rubber particles act as craze initiators rather than craze terminators. Due to poor overlapping of stress fields around the particles, no extensive shear yielding took place during the fracture process, leading to unstable macroscopic behavior. For the samples with MLTs smaller than brittle-ductile transition, a necked region developed. The stability of necked region increased with PB-g-SAN content, which resulted in improved post yield deformation stability. This process was accompanied by the participation of larger volume of material in the deformation process and strong overlapping of the stress field around the particles, which facilitated matrix shear yielding. Based on macroscopic response, this delocalized deformation manifested itself by a gradual decrease in load drop after yielding point. For the samples with PB-g-SAN content higher than 75 wt%, the great reduction in MLT and direct interconnection between the neighbor rubber particles caused the appearance of rubbery behavior. These results were also confirmed by analyzing of the fractured surfaces.     

Fabrication of Schottky diode based on Zn electrode and polyaniline doped with 2-acrylamido-2-methyl-1-propanesulfonic acid sodium salt

The electrical properties, including current-voltage (I-V) and capacitance-voltage (C-V) characteristics, of ITO/polyaniline/Al and ITO/polyaniline/Zn Schottky diodes have been investigated. Polyaniline (PANI) was prepared chemically and doped with 2-acrylamido-2-methyl-1-propanesulfonic acid sodium salt (AMPSNa). The maximum conductivity value for PANI-AMPSNa films was 1.8 × 10⁻² S/cm at 0.5 weight ratio of AMPSNa. The values of various junction parameters such as ideality factor, barrier height and charge carrier concentration were calculated based on the thermionic emission theory. Zn electrode showed better rectifying behavior with PANI-AMPSNa film than Al electrode. The obtained C-V characteristics showed that the charge carrier concentration is in the range of 10¹⁶/cm³.     

Proton conducting properties of ionically cross-linked poly(1-vinyl-1,2,4 triazole) and poly(2-acrylamido-2-methyl-1-propanesulfonic acid) electrolytes

The synthesis and thermal as well as proton conducting properties of complex polymer electrolytes based on poly(2-acrylamido-2-methyl-1-propanesulfonic acid) PAMPS and poly(1-vinyl-1,2,4-triazole) PVTri were investigated. The materials were produced by complexation of PAMPS with PVTri at various compositions to get PVTriP(AMPS) _x where x is the molar ratio of the polymer repeating units and varied from 0.25 to 4. The structure of the materials was confirmed by FT-IR spectroscopy. The TGA results verified that the polymer electrolytes are thermally stable up to approximately 200 °C. The DSC and SEM results demonstrated the homogeneity of the materials. The electrochemical stability of the materials was studied by cyclic voltammeter (CV). Proton conductivity, activation energy, and water/methanol uptake of these membranes were also measured. After humidification (RH = 50%), PVTriP(AMPS)₂ and PVTriP(AMPS)₄ showed proton conductivities of 0.30 and 0.06 S/cm at 100 °C, respectively.     

Associated structures of aqueous solution of comblike polymers from 2-acrylamido-2-methyl-1-propanesulfonic acid, dodecylmethacrylate and poly(ethyleneglycol) acrylate macromonomer

Water soluble surface active comb like terpolymers consisting of 0.66:0.22:0.12m (A) and 0.37:0.52:0.11m (B) of 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPS), dodecylmethacrylate (DoDMAc) and poly(ethylene glycol) monomethacrylate (PEGAc) macromonomer have been designed. The molecular weights of the polymers A and B are estimated to be 9.64×10⁴ and 9.52×10⁴. It is demonstrated that polymer A promotes intermolecular aggregated structures in contrast to polymer B favoring isolated micellar assemblies. The compact coil structures from polymer B effect considerable reduction in interfacial tension of octadecane/water interface to 14.6 mN m⁻¹.     

Syntheses and antitumor activities of polymers containing 2-acrylamido-2-methyl-1-propanesulfonic acid or 5-fluorouracil

Summary The polymers containing 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPA) were prepared by radical polymerizations. The polymers were identified by FT-IR, ¹H-, and ¹³C-NMR spectroscopies. The contents of AMPA unit in poly(AMPA-co-MAH), terpoly(AMPA-MAH-FUR), and poly(AMPA-co-EETFU) were 67, 73 and 49 mol %, respectively. The number average molecular weights of the polymers determined by GPC were in range from 5,600 to 9,200. The IC₅₀ values of the synthesized polymers against cancer cell lines were in the range of 0.02 to 127. The in vivo antitumor activities of polymers against Balb/C mice bearing the sarcoma 180 tumor cells were greater than those of 5-FU. Received: 6 September 2000/Revised version: 12 March 2001/Accepted: 22 March 2001     

New highly proton-conducting membrane poly(vinylpyrrolidone)(PVP) modified poly(vinyl alcohol)/2-acrylamido-2-methyl-1-propanesulfonic acid (PVA-PAMPS) for low temperature direct methanol fuel cells (DMFCs)

A new type of chemically cross-linked polymer blend membranes consisting of poly(vinyl alcohol) (PVA), 2-acrylamido-2-methyl-1-propanesulfonic acid (PAMPS) and poly(vinylpyrrolidone) (PVP) have been prepared and evaluated as proton conducting polymer electrolytes. The proton conductivity (σ) of the membranes was investigated as a function of cross-linking time, blending composition, water content and ion exchange capacity (IEC). Membranes were also characterized by FT-IR spectroscopy, thermogravimetric analysis (TGA), and the differential scanning calorimetry (DSC). Membrane swelling decreased with cross-linking time, accompanied by an improvement in mechanical properties and a small decrease in proton conductivity due to the reduced water absorption. The membranes attained 0.088 S cm⁻¹ of the proton conductivity and 1.63 mequiv g⁻¹ of IEC at 25±2 °C for a polymer composition PVA-PAMPS-PVP being 1:1:0.5 in mass, and a methanol permeability of 6.1×10⁻⁷ cm² s⁻¹, which showed a comparable proton conductivity to Nafion 117, but only one third of Nafion 117 methanol permeability under the same measuring conditions. The membranes displayed a relatively high oxidative durability without weight loss of the membranes (e.g. 100 h in 3% H₂O₂ solution and 20 h in 10% H₂O₂ solution at 60 °C). PVP, as a modifier, was found to play a crucial role in improving the above membrane performances.     

A new proton conducting membrane based on copolymer of methyl methacrylate and 2-acrylamido-2-methyl-1-propanesulfonic acid for direct methanol fuel cells

In this paper, a new kind of copolymer methyl methacrylate and 2-acrylamido-2-methyl-1-propanesulfonic acid (PAMPS-co-MMA) was synthesized by free radical polymerization. IR-spectrum and ¹H NMR were used to confirm the structure of the copolymers, and the thermal character of the copolymers was investigated with TGA and DSC. Flexible and transparent membranes based on this kind of copolymer were prepared by solution casting method. The physical properties including ionic exchange capability (IEC), water uptake, proton conductivity, methanol permeability and morphology of the membranes were investigated. These membranes showed higher water uptake though they had lower IEC compared with Nafion-117. The proton conductivity of the membrane with IEC of 0.9 mmol/g was 1.14 × 10⁻² S/cm and its methanol permeability coefficient was 5.46 × 10⁻⁷ cm²/s, much lower than that of Nafion-117. Tests on cells were also carried out to measure the performance of the membrane.     

Influence of grafting conditions on the properties of polyacrylamide-based cation-exchange cryogels grafted with 2-acrylamido-2-methyl-1-propanesulfonic acid

The effects of grafting conditions on the properties of a novel cation-exchange cryogel by grafting of 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPSA) onto polyacrylamide-based cryogel (pAAm cryogel) using potassium diperiodatocuprate (Cu(III) solution) as initiator were investigated experimentally. The basic cryogels were saturated with the initiator solution followed by the solution of monomers to get the expected sulfo groups under various grafting conditions, such as concentrations of monomers and initiator, graft reaction time, graft temperature and the volume ratio of Cu(III) to NaOH. The results showed that these factors influenced the liquid dispersion behaviors and the flow resistance as well as the protein binding capacity of the grafted cryogels. Protein binding capacity increased with the increase of concentration of AMPSA and Cu(III), the graft temperature and the graft reaction time in a wide range under the present conditions. Compared with these factors, the volume ratio of Cu(III) to NaOH in the initiator solution in the considered situations had a relatively weaker influence on the cryogel microstructures and protein binding capacity. The maximum binding capacity of lysozyme reached 2.5 mg/mL cryogel in these grafted cryogels.     

Hydrogels from 2-(dimethylamino)ethylacrylate with 2-acrylamido-2-methyl-1-propanesulfonic acid: synthesis,characterization, and water-sorption properties

A novel series of copolymer hydrogels of 2-(dimethylamino)ethylacrylate (DMAEA)/2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) were prepared by solution free radical polymerization at different feed monomer mol ratios. The monomer reactivity ratios were determined by Kelen–Tüdös method. According to that, the monomer reactivity ratios for poly(DMAEA-co-AMPS) were r₁ = 0.125 and r₂ = 2.85, (r₁ × r₂ = 0.356). The effect of reaction parameters, including the concentration of cross-linking reagent N,N′-methylene-bis-acrylamide (MBA) and initiator ammonium persulfate (APS), the monomer concentration, pH, temperature, salt solutions, and solvent polarity on the water absorption have been also studied. The hydrogels achieved water-absorption values of 430 g of water/g of xerogel for the copolymer 1:2 richest in AMPS moiety. This copolymer is also very stable to the temperature effect. The optimum pH for the copolymers is 7. Aqueous solutions of the copolymers showed lower critical solution temperature behaviour (LCST). The phase transition temperatures of aqueous solutions of these copolymer increased with increasing of hydrophilic AMPS unit content in the copolymers. The glass transition temperature (Tg) of hydrogels showed a decrease by increasing of comonomer DMAEA content.     

Synthesis and Characterizations of Macroporous Poly(acrylamide-2-acrylamido-2-methyl-1-propanesulfonic acid) Hydrogels for In Vitro Drug Release of Ranitidine Hydrochloride

Macroporous hydrogels were prepared with acrylamide (AM) and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) as well as with anhydrous dextrose (AD) as porogen by crosslinking with N,N¹-methylenebisacrylamide (MBA). The chemical structure of hydrogels is characterized by Fourier transform infrared (FTIR) spectroscopy. Morphological studies done by scanning electron microscopy (SEM) showed the macroporous nature of the hydrogels. Swelling studies of hydrogels were done in distilled water, in aqueous NaCl solution and in different pH solutions. In addition, drug release studies of selected macroporous hydrogels (DAMPS1, DAMPS4, DAMPSM1 and DAMPSM3) are also investigated.     

Synthetic absorbent for dyestuffs based on gamma crosslinked poly(vinyl alcohol) (PVA)

This work reports on the characterization and uses of gamma radiation‐crosslinked poly(vinyl alcohol) (PVA) films as absorbents for different classes of dyestuffs normally released from textile factors. Dyestuffs were selected from different producers. These dyestuffs were Remacryl Blue (basic dye), Remazol Golden Orange (reactive dye), Solar Orange (direct dye), and Sandolan (acid dye). The percentage dye sorption by PVA was determined by spectroscopic analysis and color‐strength measurements of the PVA films after absorbing the different dyestuffs. The results showed that the concentration of dimethylbisacrylamide as a crosslinking agent has a great effect on the gel fraction and percentage swelling in water of the PVA polymer. In general, crosslinked PVA showed a low tendency to absorb the different dyestuffs under investigation at room temperature. This tendency was shown to increase with an increasing temperature of the dye solution from room temperature to 70°C. Meanwhile, the highest percentage of dye sorption was found in the case of the basic dye and the lowest one in the case of the reactive dye depending on the active groups on the dyes. Moreover, the percentage dye sorption by PVA was slightly higher in the acid medium rather than in the alkaline one. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 349–354, 2003     

Ultrasonic characterization of water sorption in poly(2-hydroxyethyl methacrylate) hydrogels

A complex mechanism characterizes the water uptake kinetics in hydrogels, as a consequence of the strong structural changes occurring in the material during the sorption process. The water sorption involves the transformation of a glassy, moderately crosslinked polymer in a rubbery material. In this study, the changes in the ultrasonic attenuation and velocity in crosslinked poly(2-hydroxyethyl methacrylate) [poly-(HEMA)] hydrogel films during water sorption are measured by scanning laser acoustic microscopy (SLAM) and a pulse–echo system. In particular, the pulse–echo technique provides additional valuable information, thanks to its capability for monitoring the position of the swollen/unswollen fronts during water sorption. The evolution of the attenuation observed by SLAM is analyzed in terms of reflections on macroscopic discontinuities and absorption mechanisms. Finally, the propagation of ultrasonic waves acts as a dynamic mechanical test of the material; and, therefore, the measured longitudinal velocity and ultrasonic attenuation are applied to the calculation of the storage bulk longitudinal modulus of the poly(HEMA) hydrogels during water sorption. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:823–831, 1998     

Sorption for removing Lauths Violets in aqueous solutions by chemically crosslinked poly(AAm-co-SA) hydrogels

Summary Superswelling poly(acrylamide-co-sodium acrylate) hydrogels were prepared by free radical polymerization in aqueous solution of acrylamide (AAm) with sodium acrylate (SA) as comonomer and a multifunctional crosslinker such as trimethylolpropane triacrylate (TMPTA). In the sorption studies, binding of a cationic dye such as Lauths Violet (Thionin, LV) onto chemically crosslinked poly(AAm-co-SA) hydrogels has been investigated. Sorption of LV onto poly(AAm-co-SA) hydrogels was studied by batch sorption technique at 25°C. In the experiments of the sorption, C type sorption in the Giles classification system was found. Some binding parameters such as initial binding constant (K_i), equilibrium constant (K), monolayer coverage (n), site-size (u), and maximum fractional occupancy (O) for poly(AAm-co-SA) hydrogels-LV binding system were calculated by using Klotz and Scatchard linearization methods. Finally, the mass of sorbed LV per gram of dry hydrogel (q) was calculated to be 3,9–5,9mg LV per gram for hydrogels.     

Ultrasonic wave attenuation during water sorption in poly(2-hydroxyethyl methacrylate) hydrogels

A scanning laser acoustic microscope (SLAM) was used to measure the acoustic attenuation during water sorption in a film of crosslinked poly(2-hydroxyethyl methacrylate) [poly(HEMA)] hydrogel. The contribution of reflection, scattering, and absorption of acoustic waves to the measured attenuation is evaluated. The analysis of a model accounting only for the possible reflection of the acoustic waves at the swollen/unswollen boundaries indicates that the time dependence of the attenuation during water sorption cannot be explained simply by accounting for the presence of two additional interfaces. A predominant contribution of acoustic wave absorption during the glass transition, occurring at the two swollen/unswollen interfaces, is assumed. Also, microvoids cannot be excluded as contributors to craze growth in the glassy matrix at the penetrant/polymer interface.     

DSC studies on states of water in crosslinked poly(methyl methacrylate-co-n-vinyl-2-pyrrolidone) hydrogels

Mixtures of methyl methacrylate (MMA) with N-vinyl-2-pyrrolidone (VP) of various composition in the presence of fixed concentration of ethylene glycol dimethacrylate (EDMA) have been copolymerized to 100% conversion by γ-irradiation. The resultant solid xerogels were swollen in water to yield hydrogels of equilibrium water contents ranging from 15 to 76wt%. The state of water in the poly(MMA-co-VP) hydrogels has been studied by differential scanning calorimetry (DSC) and the percentages of free freezing, freezable bound and nonfreezing water were found to vary with the xerogel composition, i.e. the degree of hydration of the hydrogels. At low equilibrium swelling, most of the water exists as a non-freezing type, whereas at higher equilibrium swelling the majority of water exists as free freezing water. The maximum number of non-freezing water molecules per VP unit in the hydrogel is about 7.5.     

Water-soluble polyelectrolyte complexes formed by poly(diallyldimethylammonium chloride) and poly(sodium acrylate-co-sodium 2-acrylamido-2-methyl-1-propanesulphonate)-graft-poly(N,N-dimethylacrylamide) copolymers

The formation of polyelectrolyte complexes (PECs) between the cationic homopolymer poly(diallyldimethylammonium chloride) (PDADMAC) and the anionic graft copolymers poly(sodium acrylate-co-sodium 2-acrylamido-2-methyl-1-propanesulphonate)-graft-poly(N,N-dimethylacrylamide) (P(NaA-co-NaAMPS)-g-PDMAM) was studied in aqueous solution in comparison with the PECs formed between PDADMAC and the graft copolymer backbone poly(sodium acrylate-co-sodium 2-acrylamido-2-methyl-1-propanesulphonate). The turbidimetric study of the PECs formed revealed that associative phase separation is prevented when the anionic polyelectrolyte is grafted with the nonionic hydrophilic poly(N,N-dimethylacrylamide) side chains. The PECs are formed through a charge neutralisation process and they adopt a compact structure, as shown by conductivity and viscometry measurements respectively. The water-insoluble PEC core seems to be stabilised by a hydrophilic PDMAM corona, leading to the formation of nanoparticles with a hydrodynamic radius of some decades of nanometers as determined by quasi-elastic light scattering measurements.     

Dual-network hydrogels based on chemically and physically crosslinked chitosan/chondroitin sulfate

The formation of a novel type of hydrogel that combines chemically and physically crosslinked networks in a dual-network approach is presented here. Chitosan (CHT) and chondroitin sulfate (CS) were chemically modified with glycidyl methacrylate (GMA) and then crosslinked. The chemical hydrogels (CHT- and CS-gel) were deposited in different vials filled with CS or CHT stock solutions to form the dual-network hydrogels. FTIR, TGA and XRD analyses were used to characterize the chemical and the dual-network hydrogels. The percentages of CS or CHT complexed to the CHT- and CS-gel networks were calculated from the HPLC data. SEM images and swelling assays indicated that the formation of a secondary network by polyelectrolyte complexation changes the morphologies and liquid uptake capacities of the chemical hydrogels. Hence, the data and discussion presented here enable the formation of dual-network hydrogels with very interesting properties, such as the ability to interact with charged specimens (i.e., drugs, proteins or metal ions), a desirable feature for a wide range of applications.     

Preparation and properties of physically crosslinked sodium carboxymethylcellulose/poly(vinyl alcohol) complex hydrogels

A series of physically crosslinked complex hydrogels of poly(vinyl alcohol) (PVA) and sodium carboxymethylcellulose (CMC) were prepared via physical mixing and a freeze/thaw technique. The morphology of the CMC/PVA complex gels was analyzed with differential scanning calorimetry and wide‐angle X‐ray diffraction. It was found that the crystallinity and melting temperature of the complex gels decreased, whereas the glass‐transition temperature increased, with an increase in the content of CMC. The reswelling of the complex gels was pH‐responsive and relied on the content of CMC and the freeze/thaw cycles. A network structure model of the complex gel was presented. PVA crystalline regions served as physical crosslinks; the interaction between CMC and PVA resulted in intramolecular entanglements. It was also found that the model drug hemoglobin was released completely from the complex hydrogels in 4 h, and its release rate increased with an increase in the content of CMC. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Calcium ion‐induced self‐healing pattern of chemically crosslinked poly(acrylic acid) hydrogels

Poly(acrylic acid) hydrogels crosslinked with N,N′‐methylenebisacrylamide were synthesized by free radical polymerization. Polymerization conditions had a significant influence over the gel content and swelling behaviour of the hydrogels. The incorporation of calcium ions led to the origin of a self‐healing feature. The self‐healing behaviour and mechanical performance of the hydrogels were systematically investigated. The hydrogels showed good tensile strength of 1 MPa and excellent stretchable behaviour where hydrogels regained instantaneously. Hydrogel pieces joined together to become an integrated matrix as soon as two cut pieces were brought in contact. The hydrogels possessed a marked healing efficiency of 97% within 6 h at room temperature without any external intervention. The results are explained in terms of the dynamic mobility of calcium ions within the dual‐crosslinked networks of the poly(acrylic acid) hydrogels. © 2017 Society of Chemical Industry