N-dimethyl Acrylamide Research Articles

Fast and highly efficient removal of dye from aqueous solution using natural locust bean gum based hydrogels as adsorbent

For the first time, stable LBG-cl-Poly(DMAAm) hydrogel is prepared via free radical in situ polymerization of N, N-dimethyl acrylamide by employing N, N′-methylene bis(acrylamide) as cross-linkers. The hydrogel was characterized by different physicochemical techniques like equilibrium swelling percentage, point of zero charges (pHPZC), FTIR, SEM, and TGA. The LBG-cl-Poly(DMAAm) hydrogel was used in experiments on swelling behavior and adsorption of water-soluble cationic dye-Brilliant green (BG). The influence of pH on the structural change of BG dye was discussed. The swelling of hydrogel was sensitive toward the pH, ionic strength, and temperature stimuli. Adsorption behavior of hydrogel was investigated for the adsorption of BG dye and it was found to highly efficient in removing 97.7% of BG dye in 50 mg L−1 of dye solution. Adsorption data displayed that the adsorption of BG followed the pseudo-second-order kinetic model (R2 = 0.998) and Langmuir isotherm model (R2 = 0.988) with a maximum adsorption capacity of 142.85 mg g−1. The developed LBG-cl-Poly(DMAAm) hydrogel demonstrated efficient separation of BG dye and maintained maximum adsorption capacity after 6th regeneration cycles. The results indicated that LBG-cl-Poly(DMAAm) hydrogel can be used as an alternative and promising adsorbent to be applied in the treatment of effluents containing the BG dye.

Synthesis of pectin-N, N-dimethyl acrylamide hydrogel by gamma radiation and application in drug delivery (in vitro)

ABSTRACTThe objective of the work is to synthesize pectin-N, N-Dimethylacrylamide (DMAA) hydrogel by gamma radiation without using any initiators and cross-linking agents. Effect of radiation doses on gel fraction and equilibrium swelling as a function of pH were studied, and 5 kGy radiation dose was found to be the optimum dose for hydrogel synthesis. The grafting /crosslinking was investigated by Fourier transform infrared spectroscopy. Thermal properties and surface morphology were studied by differential scanning calorimetry and scanning electron microscopy. To study the drug release kinetics, 5-fluorouracil was loaded into the hydrogel and in vitro release was carried out in simulated gastric and intestinal fluid. The release profile of drug showed that more than 90% of the loaded drugs were released after 4 hours at both gastric fluid and intestinal fluid pH. Drug release data was fitted into zero order, Higuchi and Korsmeyer-Peppas kinetic models. Higuchi model was found to be the best fitted and release exponent ‘n’ value of Korsmeyer-Peppas model indicated the non-Fickian transport.

Study of congo red dye removal from its aqueous solution using sulfated acrylamide and N, N- dimethyl acrylamide grafted amylopectin

Sulfation of amylopectin, amylopectin-g-polyacrylamide and amylopectin-g-N,N-dimethyl acrylamide was carried out by using chlorosulfonic acid as the sulphating agents. The sulfated polymers were characterized by measuring degree of sulfation, FTIR and XRD studies. The three sulfated and the three unsulfated polymers were used for congo red dye adsorption from water medium. Adsorption dynamics, adsorption kinetics and adsorption isotherms of all the sulfated products were evaluated. Competitive dye removal characteristics of all the sulfated products were carried out in a mixture of congo red/methylene blue and congo red/malachite green solutions. The adsorption mechanism was studied theoretically by Density Function Theory (DFT), using Gaussian 09 programme. Sulfated products showed better dye adsorption properties than the unsulfated products where as among the sulfated products, sulfated amylopectin-g-polyacrylamide performed best. Theoretical and experimental studies showed that hydrogen bonding is mainly responsible for the dye adsorption.

Flocculation and Color Removal Performances of Polyacrylamide and Poly N, N-Dimethylacrylamide Grafted Starch: A Comparative Study

Starch-g-polyacrylamide (St-g-PAM) and Starch-g- poly (N, N-dimethylacryl amide) (St-g-PDMA) were prepared by using acrylamide (AM) and N, N-dimethylacrylamide (DMA) by Ce (IV) ion induced aqueous polymerization technique. Various grafting parameters were optimized. The so prepared graft copolymers were characterized by fourier transform infrared spectroscopy (FTIR) spectroscopy, molecular weight determination by size exclusion chromatography (SEC), thermal analysis (TGA / DTG), X-ray powder diffraction (XRD) and biodegradation studies. Flocculation performances of the graft copolymers were compared in 1.0 wt% bentonite clay, 1.0 wt % coal suspensions and 10 wt% malachite green (a textile dye) solution and in a textile dye effluent. Between the two polymers St-g-PAM and St-g-PDMA, the later showed better performance in the flocculation of bentonite and coal suspensions but the former showed better performance in the color removal from the malachite green solution and from one of the textile industrial waste water.

Suitability of polyacrylamide superabsorbent polymers as the internal curing agent of well cement

The research objectives were designed to investigate polyacrylamide superabsorbent polymers as internal curing agent to mitigate autogenous shrinkage of well cement. Results show that poly acrylamide superabsorbent polymer hydrolyzes in alkaline circumstance of cement slurry at high temperature, which causes water absorption increase and then has negative effects on thickening and compressive strength. Due to steric hindrance effect and carrying negative charge, poly acrylamide/bentonite/N,N-dimethyl acrylamide superabsorbent polymer has ability to prevent the addition reaction between hydroxyl ion and acylamino to stably exist in well cement and reduce autogenous shrinkage significantly when the dosage is 0.3wt%.

Thermo-responsive self-assembled metallomicelles accelerate asymmetric sulfoxidation in water

A series of novel chiral salen TiIV catalysts with thermo-responsive surfactant properties were prepared by covalently appending a chiral salen TiIV complex on the hydrophobic block of thermo-responsive amphiphilic copolymers of poly(N-isopropylacrylamide-co-N,N-dimethyl acrylamide) (poly (NIPAAM-co-DMAAM)). Characterization results suggested self-assembly behavior of the catalysts in water at room temperature. The self-assembled metallomicelles induced a micellar catalytic approach in asymmetric sulfoxidation in water using H2O2 as an oxidant, leading to significant rate acceleration and remarkable high selectivity. Quantitative conversion (>99%) of methyl phenyl sulfide with up to 96% chemoselectivity and 95% enantioselectivity was achieved over 0.5mol% of PN70D7-C even within 30min, whereas neat complex was far less efficient (9% conversion with 72% chemoselectivity and 79% enantioselectivity). Moreover, the catalysts could be easily recovered by thermo-controlled separation and be efficiently reused for several cycles.

Synthesis, Characterization, Swelling Studies and Dye Removal of Chemically Crosslinked Acrylic Acid/Acrylamide/N,N-Dimethyl Acrylamide Hydrogels

Polymeric hydrogels of acrylic acid (AA), acrylamide (AAm) and N,N-Dimethylacrylamide (DMAm) were prepared by free-radical polymerization at 70°C in methanol, using allylpentaerythritol (APE) as a multifunctional crosslinker and benzoyl peroxide (BPO) as an initiator. The effects of DMAm concentration and variation of pH solutions on the swelling behavior of polymers were investigated. Also AA/AAm/DMAm hydrogel was used in experiments on adsorption of a water soluble monovalent cationic dye such as Basic Blue 9 (BB-9; Methylene blue). FT-IR results confirmed the Structural features of the obtained hydrogels. Results from SEM observation showed a three dimensional porous structure of the hydrogels. Thermogravimetric analysis (TGA) of hydrogels was performed to investigate the thermal properties. The swelling results showed an increase of the swelling of AA/AAm/DMAm hydrogels as the content of DMAm increases in the hydrogel. The swelling percentage and swelling kinetics parameters such as initial swelling rate and swelling rate constant were determined. It was also shown that the swelling of hydrogels increased with the increase of pH and the maximum extent was reached at pH 8 in all compositions. The uptake of BB-9 to AA/AAm/DMAm hydrogel is studied by batch adsorption technique at 25°C. The hydrogel in the dye solution showed coloration. Kinetics and isotherms of dye adsorption were also studied. It was found that the adsorption kinetics of hydrogels followed a pseudo-second-order model. Equilibrium isotherms were analyzed using the Langmuir and Freundlich isotherms. It was seen that the Freundlich model fits the adsorption data better than the Langmuir model.

A novel ternary copolymerized polyzwitterionic of poly (AM/DMAM/MAEDAPS): synthesis and solution properties

3-[2-(N-methylacrylamido)-ethyldimethylammonio] propanesulfonate (MAEDAPS), a novel zwitterionic monomer, was designed and synthesized in this study. Then it reacted with acrylamide and N, N-dimethyl acrylamide by free radical polymerization in aqueous solution with ammonium persulfate ((NH4) 2S2O8) and sodium sulfite (NaHSO3) as initiator. The structure of MAEDAPS was characterized by 1H NMR and IR. Thermal stability of the obtained copolymer was tested by DSC, TGA and TG-IR analysis. Glass transition temperature (Tg) and melt temperature (Tm) was observed by DSC, meanwhile, the thermal degradation process was studied via TGA and TG-IR. It turned out that the thermal degradation process can be divided into three stages including removal of physically absorbed water, decomposition of side groups and degradation of polymer main chain. Anti-polyelectrolyte behavior was observed based on the intrinsic viscosity. Solution properties of ternary copolymer were exhibited by reduced viscosity. The result showed that the addition of small molecular electrolytes weakened the coulomp attraction between sulfonic acid group and quaternary ammonium group, and the conformation became extend, which led to the increase of hydrodynamic volume and reduced viscosity. The ability of monovalent and divalent cationic charges influencing the viscosity of zwitterionic copolymer obeyed the following sequence: K+ < Li+ < Na+, Cu2+ < Ca2+ < Mg2+, and anions was in the order: Cl−< I−< Br−.

The Novel Fluid Loss Additive ANMG1305 for Oil Field Cementing

Fluid loss additive is the main component of the cementing fluid. This article use monomer the monomers of 2-acrylamido-2-methyl-propanesulphonic acid (AMPS) and N, N-dimethyl acrylamide (DMAA) by the method of aqueous solution polymerization to synthesis the novel fluid loss additive ANMG1305. Discuss the amount of initiator, the molar ratio of monomer, reaction temperature, which the influence on the properties of the polymer. Through the infrared spectrum, thermo-gravimetric analyzer, viscometer, such as instrument on its microstructure and properties were characterized. We know that all the monomers are involved in the reaction and the polymer has an excellent thermal stability though the microstructural characterization and application performance of the novel fluid loss additive.

Effect of solid loading on gelcasting of silica ceramics using DMAA

Silica ceramics with low porosity, high strength, low dielectric constant and loss were fabricated by gelcasting using a low-toxicity N′N-dimethyl acrylamide (DMAA) gel system. Effect of solid loading on rheological properties of slurries, properties of green bodies and sintered ceramics were investigated. The solid loading of suspension that can meet requirements for casting is as high as 68 vol%. However, it is found that the highest flexural strength of 15.4 MPa for green bodies and 67.4 MPa for sintered ceramics is obtained at the solid loading of 64 vol% and 66 vol%, respectively. Ceramics with dielectric constant of 3.27 and the lowest dielectric loss (1 MHz) of 7.82×10 –4 are obtained at the solid loading of 64 vol%. Solid loading has a critical effect on properties of green and sintered silica bodies.

The novel fluid loss additive HTF-200C for oil field cementing

Abstract The domestic fluid loss additives often have lower thermal stability and poor salt-tolerance and their comprehensive properties are not good enough. To solve the problems, a novel cement fluid loss additive HTF-200C, which can resist high temperature and high salt content, was synthesized using the monomers of 2-acrylamido-2-methyl-propane sulphonic acid (AMPS), N, N-dimethyl acrylamide (DMAA) and a new compound with double carboxyl by the method of aqueous solution polymerization. The microstructural characterization and application performance of HTF-200C show that the polymer with the structure of all the monomers has an excellent thermal stability and strong salt tolerance, and can be used in 200 °C or in saturated brine. And the problem of the normal fluid loss additive being easy to hydrolyze due to high temperature can be solved with HTF-200C. What's more, it can also deal with the bulge of thickening curve in consistency test. The cement slurry prepared mainly by HTF-200C presents good comprehensive properties such as low filtration, high thermal stability, strong salt tolerance, rapid development of strength in low temperature, without far delayed solidification, short transit time during thickening process, and so on. The cementing job quality of Well Chengu 1-3 in the Liaohe Oilfield is excellent after it is used.

Cellulose- g-PDMAam copolymers by controlled radical polymerization in homogeneous medium and their aqueous solution properties

Water-soluble cellulose- graft-PDMAam copolymers were prepared by single-electron-transfer living radical polymerization (SET-LRP). Cellulose based macroinitiator for SET-LRP with a degree of substitution DS ≈ 2 was synthesized from softwood dissolving pulp in a homogeneous LiCl/DMAc solution. The macroinitiator was then grafted using N, N-dimethyl acrylamide (DMAam) in DMSO. Formation of cellulose- g-DMAam copolymers were confirmed by ATR–FTIR, 1H and 13C NMR spectroscopy and SEC analyses. Light scattering and steady–shear viscosity measurements revealed that the studied chain length of grafts (DP graft) had only minor effects on the solution properties of cellulose- g-PDMAam copolymers. SLS studies suggested a loose, solvent-draining architecture of the cellulose- g-PDMAam copolymer particles in H 2O.

Dynamic cell behavior on synthetic hydrogels with different charge densities

A series of poly(NaSS-co-DMAAm) hydrogels with ζ potentials (ζ) in the range −8.8–−20.5 mV and a constant Young's modulus (E) of ca. 200 kPa were designed for studying the effect of the charge density of hydrogels on dynamic cell behavior. The ζ was adjusted by tuning the molar friction of negatively charged sodium p-styrene sulfonate (NaSS) contained in the monomer mixture [NaSS and N, N-dimethyl acrylamide (DMAAm)] for gelation. A critical ζ potential, which controls cell behavior, ζcrit = −14.0 mV, was observed. When ζ > ζcrit, the cells exhibited a small spreading area, fast migration velocity, and a large migration distance, with concurrent deficiency in actin fibers and less prominent focal adhesions. Conversely, when ζ ≤ ζcrit, the cells exhibited a large spreading area, slow migration velocity, and a short migration distance, with concurrent well-developed actin fibers and prominent focal adhesions. Furthermore, cells repeatedly oscillated in a stick–slip mode from a spreading shape to a round shape on the hydrogels with ζ > ζcrit, although were unable to proliferate. The cell behavior is well correlated with the adsorbed fibronectin on the hydrogel surfaces.

Molecularly imprinted polymer catalysis of a Diels-Alder reaction

A series of synthetic polymers were designed and synthesized for enhancing the rate of the Diels-Alder cycloaddition reaction of 1,3-butadiene carbamic acid benzyl ester ( 1) and N, N-dimethyl acrylamide ( 2), to yield the corresponding endo- ( 3) and exo- ( 4) reaction products. Putative transition state analogues (TSAs) for the endo- ( 5) and exo- ( 6) reaction pathways were used as templates for the synthesis of molecularly imprinted methacrylic acid (MAA)–divinylbenzene (DVB) copolymers. The polymer system utilized was selected based upon a series of 1H NMR studies of complex formation between template and a functional monomer analogue ( K d (app) ≈ 70 mM, d 8-toluene, 293 K). Batch binding studies revealed that the imprinted polymers were selective for the TSA corresponding to the template used in the polymer synthesis. Studies on the influence of the polymers on the catalysis of the reaction of 1 and 2 demonstrated a 20-fold enhancement of the rate of the reaction relative to the solution reaction. A surprising temperature dependence of the reaction of 1 and 2 in the presence of the polymers was observed, which provides support for the role of template-functional monomer complexes in the catalysis of the Diels-Alder reaction.

Gelcasting of Carbide Ceramics

In this paper, the aqueous gelcasting of carbide ceramics (SiC, TiC, and B4C) were studied systematically. N, N-dimethyl acrylamide (DMAA) and N, N’-methylenebisacrylamide (MBAM) are used as organic monomer and cross-linker respectively. The initiator was selected from ammonium persulfate (APS) and 2, 2’-azobis[2-(imidazolin-2-yl) propane]dihydrochloride (AZIP2HCl) in accordance with the dispersant used. After gelcasting and drying, SiC samples can be densified by pressureless sintered at 2000°C. The gelcasted TiC green samples can be densified at 1530°C in vacuum with the strength as high as 1062.7749.81. The gelcasted B4C samples can be easily densified at 2250°C by pressureless sintering with the relative density around 96.2%. Results showed that it was possible to prepare carbide ceramics with complex shape and satisfied mechanical properties by gelcasting.

Immobilization of trypsin by thermo-responsive hydrogel for the affinity separation of trypsin inhibitor

A series of thermo-responsive hydrogels were synthesized from N-isopropylacrylamide (NIPAAm), glycidyl methacrylate (GMA), and N, N-dimethyl acrylamide (DMA). The effect of the different monomer ratios of GMA/DMA in the copolymeric hydrogel on the swelling behaviors, physical properties, and drug release behavior was investigated. Results showed that the swelling ratio in deionized water increased with an increase of content of DMA in the copolymeric hydrogel. However, the compressive modulus, crosslinking density, and mechanical strength decreased with increasing DMA content in the copolymeric hydrogel. In addition, the influence of the copolymeric composition on the immobilization of enzyme on the poly(NIPAAm-co-GMA-co-DMA) hydrogel which was used as a support to immobilize trypsin was also investigated. The result showed that the copolymeric hydrogel showed a good immobilized capacity of trypsin. The immobilized trypsin as a ligand of affinity chromatography having fifty three percent activity of trypsin inhibitor in the crude extract of sweet potato can be recovered by affinity chromatography. The molecular weights of the purified trypsin inhibitors are more than 20 kDa by SDS-PAGE.

Novel iniferter-based synthetic approach to hetero-telechelic precursors and multiblock copolymers composed of vinyl polymer blocks and condensation linkages

A novel synthetic approach, leading to the formation of hetero-telechelic precursors and multiblock copolymers composed of vinyl polymer [polystyrene or poly( N, N-dimethylacryl amide)] blocks and condensation linkages (ester or amide) or its polycondensate blocks, was developed using iniferters containing two different types of functional group (hydroxyl, carboxyl or amine) in their molecules via two different routes, each of which consisted of two-step reactions: photoiniferter living radical polymerization and subsequent polycondensation or vice versa. Both reactions proceeded at room temperature. The formation of multiblock copolymers was confirmed by 1H NMR and IR spectroscopic measurements and molecular weight measurements. Irrespective of the type of iniferter, the livingness of the iniferter polymerization step was verified by a linear relationship between the conversion and molecular weight under appropriate reaction conditions, indicating that the vinyl polymers’ block lengths were well controlled. The decrease in molecular weight of copolymers subjected to mild alkaline hydrolysis indicated that these multiblock copolymers might be degraded in a living body. This study is preliminary, but synthetic strategy proposed here may enable various choices of macromolecular architecture. Once the optimized reaction condition is achieved, functional macromolecular architectures with sequentially ordered complexity including well-controlled block lengths and multiple condensation linkages are feasible.

Remarkable Lewis acid effects on polymerization of functionalized alkenes by metallocene and lithium ester enolates

Drastic effects of Lewis acids E(C 6F 5) 3 (E = Al, B) on polymerization of functionalized alkenes such as methyl methacrylate (MMA) and N, N-dimethyl acrylamide (DMAA) mediated by metallocene and lithium ester enolates, Cp 2Zr[OC(O i Pr) CMe 2] 2 ( 1) and Me 2C C(O i Pr)OLi, are documented as well as elucidated. In the case of metallocene bis(ester enolate) 1, when combined with 2 equiv. of Al(C 6F 5) 3, it effects highly active ion-pairing polymerization of MMA and DMAA; the living nature of this polymerization system allows for the synthesis of well-defined diblock and triblock copolymers of MMA with longer-chain alkyl methacrylates. In sharp contrast, the 1/2B(C 6F 5) 3 combination exhibits low to negligible polymerization activity due to the formation of ineffective adduct Cp 2Zr[OC(O i Pr) CMe 2] +[O C(O i Pr)CMe 2B(C 6F 5) 3] − ( 2). Such a profound Al vs. B Lewis acid effect has also been observed for the lithium ester enolate; while the Me 2C C(O i Pr)OLi/2Al(C 6F 5) 3 system is highly active for MMA polymerization, the seemingly analogous Me 2C C(O i Pr)OLi/2B(C 6F 5) 3 system is inactive. Structure analyses of the resulting lithium enolaluminate and enolborate adducts, Li +[Me 2C C(O i Pr)OAl(C 6F 5) 3] − ( 3) and Li +[Me 2C C(O i Pr)OB(C 6F 5) 3] − ( 4), coupled with polymerization studies, show that the remarkable differences observed for Al vs. B are due to the inability of the lithium enolborate/borane pair to effect the bimolecular, activated-monomer anionic polymerization as does the lithium enolaluminate/alane pair.

Zwitterion effect in polyelectrolyte gels based on lithium methacrylate- N, N-dimethyl acrylamide copolymer

Zwitterionic compounds such as those based on 1-butylimidazolium-3-( n-butanesulfonate) have previously been shown to have positive effects on the transport properties of polyelectrolytes. The addition of the zwitterion has been found to, in some cases, increase the dissociation of the lithium ion and enhance the conductivity by almost an order of magnitude. In this work, we report the effects of adding the above-mentioned zwitterion into the polyelectrolyte gel system poly(lithium methacrylate-co- N, N-dimethyl acrylamide); the anionic group being a stronger base leads to different behaviour for this copolymer compared to previous work. Polyelectrolyte gels based on dimethyl sulfoxide and polyether solvents were investigated to determine the breadth of applicability of the zwitterion in improving lithium ion transport. Impedance spectroscopy and pulse field gradient-NMR diffusion indicate an increase in the number of available charge carriers with zwitterion addition in some gel systems, however, the effect is not universal.

Synthesis of amphiphilic block copolymers based on poly(dimethylsiloxane) via fragmentation chain transfer (RAFT) polymerization

Dihydroxy terminated poly(dimethyl siloxane) (PDMS) was modified to form a di(trithiocarbonate) functional molecule capable of forming tri-block copolymers via the reversible-addition-fragmentation chain transfer (RAFT) process. Two statistical copolymer blocks were grown from the central PDMS block, comprising units of N, N-dimethyl acrylamide (DMA) and 2-( N-butyl perfluorooctanefluorosulfonamido) ethyl acrylate (BFA), to form A-B-A triblock macromolecules. The molecular weight of these block copolymers were found to increase with conversion while the polydispersity of the molecular weight distribution remains under 1.25. An unusual and interesting kinetic phenomenon was observed in that the copolymerization behaviour of DMA and BFA was influenced by the initial PDMS block. We surmise that this might be a direct observation of a ‘bootstrap’ effect.