Vinyl Formamide Research Articles

Photo‐responsive systems based on anisotropic composites of poly(N‐vinyl formamide) and active fillers using directional freezing combined with gamma irradiation crosslinking

AbstractThis study deals with the fabrication of smart anisotropic composite systems capable of reacting to light stimulus and reversibly providing significant change in the length. Surface‐modified carbon nanotubes (CNTs) and poly(pyrrole) (PPy) nanotubes were used as photoactive fillers. Anisotropic composites containing these fillers and poly(N‐vinyl formamide) (PNVF) matrix were fabricated using a directional freezing technique with freezable monomer, N‐vinyl formamide (NVF), as structure guiding medium and subsequent gamma irradiation polymerization and crosslinking technique. The dielectric properties showed that there is the presence of both relaxation processes α and β, which are significantly influenced by the presence of photoactive filler. The anisotropic distribution of fillers in samples was confirmed using microscopical, electrical conductivity and mechanical properties analysis. Finally, the photoactuation capabilities were investigated and showed enhanced photoactive response for the anisotropic system in the change in the length up to 54 μm after irradiation at 627 nm with a very low light intensity of 6 mW cm−2 in a fully reversible and repeatable manner. The simple, affordable, and industrially scalable fabrication technique opens an avenue for smart anisotropic photoactive composite systems.

Stereoselective Synthesis of (E)- and (Z)-Isocyanoalkenes.

(E)- and (Z)-isocyanoalkenes were selectively synthesized via the sequential cross coupling of vinyl iodides with formamide, followed by dehydration. The optimal catalyst, generated in situ from CuII and trans-N,N'-dimethyl-1,2-cyclohexanediamine, rapidly coupled (E)- or (Z)-vinyl iodides with formamide, which minimized the isomerization of the resultant vinyl formamide. The method efficiently provided a range of acyclic, carbocyclic, and heterocyclic isocyanoalkenes; the versatility is illustrated with the selective, stereodivergent syntheses of the diastereomeric isocyanoalkene antibiotics, B371 and E-B371.

Synthesis and Characterization of Functional Monomer N‐Vinyl Formamide (NVF)

AbstractN‐vinyl formamide (NVF) is successfully synthesized by using the intermediate polystyrene maleic anhydride ester. The prepared NVF owns high purity and the diacid as a by‐product of synthesis can be reused. N‐a‐hydroxyethyl formamide (NHEF) is synthesized by using acetaldehyde and formamide as raw materials in the presence of basic catalyst. Acetaldehyde is purified by distillation under reduced pressure and dried with anhydrous magnesium sulfate. Low molecular weight styrene/maleic anhydride copolymer (SMA) is synthesized by the reaction of styrene and maleic anhydride in the presence of benzoyl peroxide initiator using acetone as solvent. The intermediate polystyrene maleic anhydride ester (NHEF–ADDUCT) is synthesized with SMA and NHEF as raw materials. Finally, the obtained NHEF–ADDUCT is cracked and the target product NVF is isolated and purified. The NVF is characterized by Fourier transform infrared spectroscopy, gas chromatography (GC), 1H‐NMR, and 13C‐NMR. The purity of NVF is 86.7% as measured by iodometric method and GC internal standard method, indicating the small amount of impurity formamide in it.

Metal-Polymer Complexes of Gallium/Gallium-68 with Copolymers of N-Vinylpyrrolidonewith N-Vinylformamideand N-Vinyliminodiacetic Acid: A Hint for Radiolabeling of Water-Soluble Synthetic Flexible Chain Macromolecules.

Copolymer of N-vinylpyrrolidone (VP) with vinylformamide (VFA) and N-vinyliminodiacetic acid (VIDA) was synthesized; its metal-polymer complexes (MPCs) with gallium were obtained. The complexes were characterized by size exclusion chromatography, hydrodynamic and optical methods, scanning electron microscopy, and spectral methods (UV, IR, 1Н NMR spectroscopy). It was demonstrated that in going from polymer to complex, hydrodynamic parameters of macromolecules change only slightly, although the polymer contains intramolecular Ga(VIDA)2 fragments in its structure. A new method for preparation of MPCs with gallium and gallium-68 radionuclide was suggested. The obtained metal-polymer complex is stable over a wide range of pH values as well as in the histidine challenge reaction. In vivo distribution experiments in intact animals showed high primary accumulation of thegallium-68 MPC in blood with subsequent excretion via urinary tract.

Sodium alginate grafted poly(N-vinyl formamide-co-acrylic acid)-bentonite clay hybrid hydrogel for sorptive removal of methylene green from wastewater

The treatment of industrial effluents is highly desirable due to the presence of numerous toxic, non-biodegradable and water soluble dyes which adversely affect living organisms and the environment. Sorptive treatment of these contaminants by using hydrogel sorbents may be a fascinating approach due to facile operation, high efficacy, simple synthesis, rapid recovery and subsequent reuse of hydrogels. Therefore, a novel sodium alginate grafted and bentonite clay doped poly (N-vinyl formamide-co-acrylic acid-)[SA-g-p(VFA-co-AAc)/BC] hydrogel was fabricated from acrylic acid (AAc), N- vinyl formamide (VFA) and bentonite clay (BC). The percent swelling of hybrid material was comprehensively investigated at different pH in Milli-Q distilled water. The composite material absorbed water by Fickian diffusion and attained equilibrium in 23 h with corresponding maximum swelling capacity of 8049 %. The sorption potential of the anionic hydrogel was thoroughly inspected at pH 7 by using methylene green (MG) as a cationic probe dye in aqueous medium. During batch sorption experiments, conditions for maximum removal of MG were optimized by investigating the effect of agitation time, MG- concentration, solution temperature and pH. The resultant sorption data obeyed the pseudo second order kinetic and Langmuir isotherm models which unambiguously reflected chemisorption of MG onto the hybrid material owing to the ionic interaction of sorbent with the dye. The outstanding swelling (8049 %) and sorption capacities (2108 mg g−1) make the hybrid hydrogel a viable superabsorbent and sorbent for relevant industrial and environmental applications.

Characterization of poly (N‐vinyl formamide) by size exclusion chromatography–multiangle light scattering and asymmetric‐flow field‐flow fractionation–multiangle light scattering

ABSTRACTThe molar mass and the radius of gyration of three poly N‐vinyl formamide (polyNVF) synthesized in aqueous solution polymerization were characterized using two different fractionation techniques: size exclusion chromatography (SEC) and asymmetric‐flow field‐flow fractionation (AF4) coupled with a multiangle light scattering (MALS) and a refractive index (RI) detector. For the sake of comparison, the polymers were also characterized by MALS using the Zimm plot approach (no fractionation). The dn dc−1 of the poly (N‐vinyl formamide) was measured (0.1564 mL g−1) and it was found to be insensitive to the molar mass (in the range 150–450 kDa) and also to the eluents used (DDI water or mixed eluent DDI water/acetonitrile (80 : 20) at pH = 5.5). Interestingly, the concentrations of the samples injected in the SEC and AF4 should be different because concentrations in the range of 20–40 mg mL−1 used for the AF4 caused overloading and anomalous elution in the SEC and hence misleading molar masses. At adequate concentrations in each fractionation equipment, the molar masses were in reasonable good agreement although AF4/MALS provided larger values than the other two techniques likely because samples were not filtered before injection. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42434.

Synthesis and characterization of poly(N-vinyl formamide) hydrogels-A potential alternative to polyacrylamide hydrogels

The synthesis and characterization of solution-cast, molded gels of N-vinyl formamide (NVF) has not been previously reported even though NVF is an isomer of acrylamide (AAm) and polyacrylamide (PAAm) hydrogels have many commercial applications. Aqueous NVF solutions were cross-linked into gels using a novel cross-linker, 2-(N-vinylformamido)ethylether, and the thermally-activated initiator VA-044. For a given formulation, PNVF gels swell up to twice that of PAAm gels cross-linked with N,N′-methylenebisacrylamide. From swelling and compression measurements, PNVF gels were found to be more hydrophilic than PAAm gels. Flory-Huggins solubility parameters were χ = 0.38ϕ2 + 0.48 for PNVF and χ = 0.31ϕ2 + 0.49 for PAAm, where ϕ2 is the polymer volume fraction. The shear moduli for PNVF and PAAm scale with ϕ and ϕ respectively, consistent with good solvent behavior, also suggesting PNVF is more hydrophilic than PAAm. Similarity of mechanical properties for both gels as a function of ϕ2 suggests that network structures of PNVF and PAAm gels are similar. Fracture strains of both gels declined with ϕ2 by the same linear function while fracture stresses were about 500 kPa regardless of formulation. Since NVF is a liquid monomer, less toxic than AAm and can be hydrolyzed to a cationic form, PNVF gels could become technologically significant. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013

Chemically modifiable fluorinated copolymer nanoparticles for 19F‐MRI contrast enhancement

AbstractRecently there has been interest in developing imaging contrast media for magnetic resonance imaging (MRI) that contain biologically rare, magnetically active nuclei such as fluorine. In principle, fluorinated contrast agents can be used to generate highly selective 19F magnetic resonance images that can be superimposed over complimentary 1H magnetic resonance images to provide an anatomical context for the fluorinated contrast agent. Additionally, nanoparticles can be made to target various pathological sites via active and passive targeting mechanisms. In this study, fluorinated nanoparticles were produced using a free radical polymerization of vinyl formamide monomers with two different fluorinated monomers. The nanoparticles showed a clear, single 19F‐NMR signal. Additionally, surface amide groups were hydrolyzed to primary amines to yield additional surface reactivity. Fluorinated nanoparticles produced using a free‐radial polymerization method yield a new nanoparticle for 19F‐MRI applications with potential for facile functionalization. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

One-Step Preparation of Uniform Cane-Ball Shaped Water-Swellable Microgels Containing Poly(N-vinyl formamide)

In this study we report the preparation of a new family of core-shell microgels that are water-swellable and have a morphology that is controllable by particle composition. Here, nearly monodisperse core-shell PNVF-xGMA [poly(N-vinylformamide-co-glycidyl methacrylate)] particles (where x is the weight fraction of GMA used) were prepared via nonaqueous dispersion (NAD) polymerization in one step. The shells were PGMA-rich and were cross-linked by reaction of epoxide groups (from GMA) with amide groups (from NVF). The core of the particles was PNVF-rich. A bifunctional cross-linking monomer was not required to prepare these new microgels. The particles had a remarkable "cane-ball"-like morphology with interconnected ridges, and this could be controlled by the value for x. The particle size was tunable over the range 0.8-1.8 μm. Alkaline hydrolysis was used to hydrolyze the PNVF segments to poly(vinylamine), PVAM. The high swelling pressure of the cationic cores caused shell fragmentation and release of some of the core polymer when the hydrolyzed particles were dispersed in pure water. The extent to which this occurred was controllable by x. Remarkably, the PGMA-rich shells could be detached from the hydrolyzed particles by dispersion in water followed by drying. The hydrolyzed PNVF-0.4GMA particles contained both positively and negatively charged regions and the dispersions appeared to exhibit charge-patch aggregation at low ionic strengths. The new cross-linking strategy used here to prepare the PNVF-xGMA particles should be generally applicable for amide-containing monomers and may enable the preparation of a range of new water-swellable microgels.

Synthesis of new hybrid material based on copolymer and Pd-nanoparticles.

ABSTRACTIn this work, the synthesis of new hybrid material based on a poly (buthyl acrylate –co- vinyl formamide) copolymer using the emulsion polymerization and doped with Pd, is discussed. The copolymer structure was confirmed by FT-IR. Afterwards, Pd nanocrystals previously synthesized, resulting on a spherical shape of ~ 5 nm, as measured by High-resolution transmission electron microscopy (HR-TEM), were deposited on the structure of the organic material. The films were analyzed using AFM and Scanning electron microscopy (SEM), giving rise to a hybrid material that could be applied in areas such as nanolithography, catalysis, and sensors.

Adsorption of Poly(vinyl formamide-co-vinyl amine) (PVFA-co-PVAm) Polymers on Zinc, Zinc Oxide, Iron, and Iron Oxide Surfaces

The adsorption of poly(vinyl formamide) (PVFA) and the statistic copolymers poly(vinyl formamide-co-vinyl amine) (PVFA-co-PVAm) onto zinc and iron metal particles as well as their oxides was investigated. The adsorbates were characterized by means of XPS, DRIFT spectroscopy, wet chemical analysis, and solvatochromic probes. Dicyano-bis-(1,10-phenanthroline)-iron(II) (1), 3-(4-amino-3-methylphenyl)-7-phenyl-benzo-[1,2-b:4,5-b']difuran-2,6-dione (2), and 4-tert-butyl-2-(dicyano-methylene)-5-[4-(diethylamino)-benzylidene]-Δ(3)-thiazoline (3) as solvatochromic probes were coadsorbed onto zinc oxide to measure various effects of surface polarity. The experimental findings showed that the adsorption mechanism of PVFA and PVFA-co-PVAm strongly depends on the degree of hydrolysis of PVFA and pH values and also on the kind of metal or metal oxide surfaces that were employed as adsorbents. The adsorption mechanism of PVFA/PVFA-co-PVAm onto zinc oxide and iron oxide surfaces is mainly affected by electrostatic interactions. Particularly in the region of pH 5, the adsorption of PVFA/PVFA-co-PVAm onto zinc and iron metal particles is additionally influenced by redox processes, dissolution, and complexation reactions.

Free‐Radical Propagation Kinetics of N‐Vinyl Formamide in Aqueous Solution Studied by PLP–SEC

AbstractThe propagation rate coefficients, kp, were determined for free‐radical polymerization of N‐vinyl formamide (NVF) in aqueous solution by pulsed‐laser‐initiated polymerization in conjunction with size‐exclusion chromatography. The polymerizations were carried out in the temperature range from 5 to 60 °C for concentrations between 3 and 100 wt.‐% NVF. A six‐fold decrease in kp was observed between polymerization of NVF in dilute aqueous solution and in bulk monomer. Intermolecular hydrogen bonding and dipolar interactions between solvent molecules and the transition state structure for NVF propagation are proposed to be responsible for these observed solvent effects, which are compared to similar effects found for the aqueous solution polymerizations of nonionized methacrylic acid and N‐vinyl pyrrolidone (NVP). Batch aqueous‐phase polymerizations of NVF and NVP demonstrate that the difference in initial rates of fractional conversion correlates with the differences in kp values for these two monomers. 2D NMR is used to study transfer reactions that occur at higher temperatures and NVF concentrations to the formic group and to the polyNVF backbone.magnified image

Self-assembly of monodisperse nanoparticles of styrene copolymers with N-vinylformamide into periodic colloidal structures

532 Studying the self-assembly of nanoparticles is important for nanotechnology, since this process is promising for the fabrication of twoand three-dimensional ordered matrices of optical elements, detectors, and sensors [1]. For example, submicron monodisperse particles of silicon dioxide or polystyrene are applied as structural elements of photonic crystals [1, 2]. The formation of periodic colloidal structures (PCS) with negatively charged polymer nanoparticles has been revealed even in dispersions at low ionic force and a volume ratio of 0.001–0.04 [3]. The action of proportional attraction and repulsion forces between particles is a necessary condition for the process. An enhancement of the ability of nanoparticles to self-assemble, provided that they have a hydrophilic surface layer, has been noted [4]. Due to the extension of chains of the layer into the aqueous phase the particles “sense” each other at distances on the order of 50 nm, which is longer than follows from the DLVO theory. These chains also facilitate a high capillary adhesion of the particles. To extend the range of nanoparticles capable of selfassembling, a series of positively charged monodisperse nanoparticles with hydrophilic surface layer and 55–110 nm in diameter with its standard deviation less than 2% was obtained via the emulsion copolymerization of styrene (St) with N -vinylformamide (VFA) (3– 7 wt %) initiated by 0.2–3.5 wt % of 2,2'-azobis-[2-(2imidazoline-2-yl)propane] dihydrochloride (AIP) in 0.9–1.5 × 10 –3 mol/l cetyltrimethylammonium bromide (CTAB) solutions with pH 3.5–6.5 at 90°e (Fig. 1). The particle size decreased in a weakly acidic medium with an increase in the VFA and AIP concentrations as a result of an increase in the amount of oligomer chains enriched in VFA units. Such chains are formed in the initial stage of the synthesis and participate in the nucleation process along with CTAB. At the initial pH below 5.8, the hydrolysis of the AIP residues yielding carboxylic groups at the ends of polymer chains caused a decrease in the surface charge and an increase in the particle size. The holding of the nanoparticles in a 1 M PHOTONIC CRYSTALS

Ionic conductivity studies of gel polyelectrolyte based on ionic liquid

Novel lithium polyelectrolyte-ionic liquids have been prepared and characterized of their properties. Poly(lithium 2-acrylamido-2-methyl propanesulfonate) (PAMPSLi) and its copolymer with N-vinyl formamide (VF) also has been prepared as a copolymer. 1-Ethyl-3-methylimidazolium tricyanomethanide (emImTCM) and N, N-dimethyl- N-propyl- N-butyl ammonium tricyanomethanide (N 1134TCM) which are chosen because of the same with the anion of ionic liquid were prepared. The ionic conductivity of copolymer system (PAMPSLi/PVF/emImTCM: 5.43 × 10 −3 S cm −1 at 25 °C) exhibits about over four times higher than that of homopolymer system (PAMPSLi/emImTCM: 1.28 × 10 −3 S cm −1 at 25 °C). Introduction of vinyl formamide into the copolymer type can increase the dissociation of the lithium cations from the polymer backbone. The ionic conductivity of copolymer with emImTCM (PAMPSLi/PVF/emImTCM) exhibits the higher conductivity than that of PAMPSLi/PVF/N 1134TCM (2.48 × 10 −3 S cm −1). Because of using the polymerizable anion it is seen to maintain high flexibility of imidazolium cation effectively to exhibit the higher conductivity. And also the viscosity of emImTCM (19.56 cP) is lower than that of N 1134TCM (28.61 cP). Low viscosity leads to a fast rate of diffusion of redox species.

Structural Basis for the Interaction of CCR5 with a Small Molecule, Functionally Selective CCR5 Agonist

The chemokine receptor CCR5 is an attractive target for HIV-1 drug development, as individuals whose cells lack surface CCR5 expression are highly resistant to HIV-1 infection. CCR5 ligands, such as CCL5/RANTES, effectively inhibit HIV-1 infection by competing for binding opportunities to the CCR5 and inducing its internalization. However, the inherent proinflammatory activity of the chemotactic response of CCR5 ligands has limited their clinical use. In this study, we found that a novel small molecule, functionally selective CCR5 agonist, 2,2-dichloro-1-(triphenylphosphonio)vinyl formamide perchlorate (YM-370749), down-modulates CCR5 from the cell surface without inducing a chemotactic response and inhibits HIV-1 replication. In molecular docking studies of YM-370749 and a three-dimensional model of CCR5 based on the rhodopsin crystal structure as well as binding and functional studies using various CCR5 mutants, the amino acid residues necessary for interaction with YM-370749 were marked. These results provide a structural basis for understanding the activation mechanism of CCR5 and for designing functionally selective agonists as a novel class of anti-HIV-1 agents.

Synthesis and characterization of xanthan gum‐g‐N‐vinyl formamide with a potassium monopersulfate/Ag(I) system

AbstractA xanthan gum‐g‐N‐vinyl formamide graft copolymer was synthesized through the graft copolymerization of N‐vinyl formamide (NVF) onto xanthan gum with an efficient system, that is, potassium monopersulfate (PMS)/Ag(I) in an aqueous medium. The effects of the concentrations of Ag(I), PMS (KHSO5), hydrogen ion, xanthan gum, and NVF along with the time and temperature on the graft copolymerization were studied by the determination of the grafting parameters (grafting ratio, add‐on, conversion, grafting efficiency, and homopolymer) and the rate of grafting. The maximum grafting ratio was obtained at a 0.6 g/dm3 concentration of xanthan gum. All the parameters showed an increasing trend with an increasing concentration of peroxymonosulfate, except the homopolymer percentage, which showed a decreasing trend. The grafting ratio, add‐on conversion, grafting efficiency, and rate of grafting increased with the concentration of Ag(I) increasing from 0.8 × 10−2 to 1.2 × 10−2 mol/dm3. The optimum time and temperature for the maximum degree of grafting were 90 min and 35°C, respectively. The graft copolymer was characterized with IR spectral analysis, thermogravimetric analysis, and differential calorimetry analysis. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1637–1645, 2006

Immunomodulating properties of homo-and copolymers of N-vinylamides

A series of new water-soluble copolymers of methacrylamidoglucose (MAG) with N-vinylamides (N-vinylformamide and N-alkyl-N-vinylacetamides) have been synthesized and characterized as modulants in BALB/C mice (i.p. administration) and by the method of local gel hemolysis. The imunostimulant action was observed for poly(vinyl formamide) in a dose of 25, 10, and 5 mg/kg and for MAG copolymers with N-octyl-N-vinylacetamide in a dose of 50 and 10 mg/kg. The other copolymers did not exhibit significant activity.

Adsorption of poly(vinyl formamide‐co‐vinyl amine) onto silica particle surfaces and stability of the formed hybrid materials

AbstractIn order to produce silica/polyelectrolyte hybrid materials the adsorption of the polyelectrolyte poly(vinyl formamide‐co‐vinyl amine), P(VFA‐co‐VAm) was investigated. The adsorption of the P(VFA‐co‐VAm) from an aqueous solution onto silica surface is strongly influenced by the pH value and ionic strength of the aqueous solution, as well as the concentration of polyelectrolyte.The adsorption of the positively charged P(VFA‐co‐VAm) molecules on the negatively charged silica particles offers a way to control the surface charge properties of the formed hybrid material. Changes in surface charges during the polyelectrolyte adsorption were studied by potentiometric titration and electrokinetic measurements.X‐ray photoelectron spectroscopy (XPS) was employed to obtain information about the amount of the adsorbed polyelectrolyte and its chemical structure.The stability of the adsorbed P(VFA‐co‐VAm) was investigated by extraction experiments and streaming potential measurements. It was shown, that polyelectrolyte layer is instable in an acidic environment. At a low pH value a high number of amino groups are protonated that increases the solubility of the polyelectrolyte chains. The solvatation process is able to overcompensate the attractive electrostatic forces fixing the polyelectrolyte molecules on the substrate material surface. Hence, the polyelectrolyte layer partially undergoes dissolving process.

Radical Grafting Polymerization of Vinylformamide with Functionalized Silica Particles

AbstractTwo different radical polymerization techniques have been applied to covalently graft vinylformamide (VFA) onto silica particles. Grafting by the polymerization of VFA using an immobilized azo initiator on silica has been found less effective, because monomer conversion is limited in non‐aqueous solvents and grafting yields are low in water. Radical copolymerization of VFA with vinyltriethoxysilane (VTS)‐functionalized silica particles is suitable to produce poly(vinylformamide) (PVFA) silica hybrid particles in respectable yield. The VFA/VTS‐silica ratio determines the degree of grafting. The PVFA‐VTS‐co‐grafted silica particles can be acidically hydrolyzed into poly(vinylamine)‐grafted silica particles. Molecular structures of the surface groups and grafted polymer chains have been confirmed by means of solid state 13C{1H} cross‐polarization magic‐angle spinning (CP MAS) NMR spectroscopy. Zeta potential measurements show the altering of the former silica particles surface charges arising from the introduction of basic groups on the surface.image

Synthesis and properties of crosslinked polyvinylformamide and polyvinylamine hydrogels in conjunction with silica particles

Polyvinylamine hydrogels with silica particles encapsulated (PVAm/silica) were produced by a two-step synthesis. In the first step, polyvinylformamide/silica (PVFA/silica) hybrids were synthesized from vinylformamide (VFA) and 1,3-divinylimidazolidin-2-one (1,3-bisvinylethyleneurea, BVU), as the crosslinker, by radical copolymerization in silica/water suspensions using different compositions of VFA/BVU. The target product PVAm/silica was obtained by acidic hydrolysis of the PVFA/silica hydrogels in a second step. The chemical structures of both hydrogels, PVFA/silica and PVAm/silica, respectively, were revealed by solid-state 13C(1H) cross-polarity/magic-angle spinning NMR spectroscopy. Both hydrogels swelled significantly in water. The swelling capacity of the two systems was characterized by the correlation length ξ (or hydrodynamic blob size) of the network meshes with small-angle neutron scattering experiments. ξ is significantly larger for PVAm/silica than for PVFA/silica, which corresponds to the observed higher swelling capacity of this polyelectrolyte material. Furthermore, the swelling behavior of the hybrid hydrogels was quantitatively described in terms of free swell capacity, centrifuge-retention capacity, adsorption against pressure, and free swell rate as compared with values of the corresponding copolymer hydrogels. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3144–3152, 2002