Acrylamide In Solution Research Articles

Environmental Degradation of Polyacrylamides

The environmental fate of a polyacrylamide thickening agent (PATA), formulated without and with a glyphosate-surfactant herbicide (GH), was examined under various environmental situations: formulation in surface water and ground water, volatility, and soil mobility. Environmental Fate of PATA in Surface Water and Ground Water:PATA was formulated at four concentrations in distilled–deionized water, three surface water samples, and two ground water samples, without and with a GH. Solutions were placed in glass bottles, covered with plastic wrap, and exposed to environmental (outdoor) conditions for 6 weeks. Acrylamide and ammonium concentration, pH, and bacterial and fungal populations were measured weekly. All solutions in this portion of the study had a homogeneous milky appearance but by the conclusions of the study were nearly transparent. The results of this study suggest that polyacrylamide can degrade to acrylamide under environmental conditions. Statistically, there was no linear correlation between the various parameters measured. Volatility:PATA was formulated without and with GH. Each solution plus an acrylamide standard (positive control) was placed in a glass beaker and exposed to environmental (outdoor) conditions for 6 days. Acrylamide concentration, ammonium concentration, pH, and solution volume were measured daily. Acrylamide and ammonium concentrations increased during the study in all formulations, except when solutions evaporated to dryness. pH did not change greatly over the course of the study for these samples. Those solutions containing PATA had a homogeneous milky appearance but by the conclusions of the study were nearly transparent. This suggests a physical structural change in the polymer. Soil Mobility:PATA formulated with GH was also applied to soil columns and soil boxes containing sand, Eudora sandy loam, Eudora sandy clay, and Kohola silt loam. Acrylamide could be detected by Day 2 in all soil columns. Acrylamide could not be detected in the runoff of any of the soil boxes.

Propagation velocity of the reaction front in addition polymerization systems

Traveling polymerization fronts in unstirred solutions of methylmethacrylate, methacrylic acid, or acrylamide with some free radicals initiators (through thermal decomposition) have been observed experimentally. A local heating of the initial reactant mixture, under suitable conditions, leads to a reaction front that propagates along the space coordinate with a constant velocity. In this article, a physical interpretation of this phenomenon is provided through a mathematical model that accounts for the depolimeri-zation reaction and is based on the constant pattern approach. Moreover, an approximate explicit analytic expression for the velocity of propagation of the polymerization front is proposed. The theoretical values are compared with those measured experimentally as a function of the initiator concentration for different addition polymerization systems.

Temperature control of highly exothermic batch polymerization reactors

In this article a highly exothermic batch polymerization reactor is considered. The reactor is simplified as a mixing tank with the internal heat generation treated as a disturbance. A fuzzy-hybrid-PID-feedback (FH-PID) control structure is developed in which the output of fuzzy hybrid portion is used to adjust the set point of a PID controller to compensate for the effect of the major disturbance, the heat of reaction. In this way, the hybrid portion of the controller does not influence the stability of the original PID control system. A fuzzy model was constructed to estimate the heat of reaction inside the fuzzy hybrid block. The fuzzy parameters of the hybrid portion do not depend on the process model and can be estimated from the transient response obtained with a conventional PID controller. This FH-PID control strategy has been applied to the temperature control of batch solution and batch inverse emulsion polymerizations of acrylamide in a 1 gallon pilot scale reactor. The results show that this fuzzy hybrid-PID-feedback control strategy improves the control performance of the batch polymerization reactor.

Polyacrylamide Gel Electrophoresis in Discontinuous Transverse Urea-Gradient Gels

Polyacrylamide gel electrophoresis in transverse urea-gradient gels is widely used for the study of changes in conformation and quaternary structure of proteins induced by increasing concentrations of urea. However, possible uncertainties regarding the effective concentration of urea at any given point across the gel must be considered when this technique is used for quantitative purposes. We describe here a simple, practical procedure for preparing urea-gradient gels discontinuously, by stacking various layers of acrylamide solution with increasing urea concentrations. We show that the urea concentration in different lanes of discontinuous gradient gels prepared in this way can be predetermined accurately enough for quantitative purposes and provide as an example the study of the dissociation of thyroglobulin in urea. Various levels of resolution can be attained by this technique. The use of discontinuous gradient gels may extend the usefulness of urea gel electrophoresis in relation with the quantitative aspects of the study of protein conformation.

Use of combined shear and pressure acoustic waves to study interfacial and bulk viscoelastic effects in aqueous polymeric gels and the influence of electrode potentials

AT-cut quartz crystals operating in the thickness-shear mode at 10 MHz have been used to study the viscoelastic changes occurring during the polymerization and gelling of acrylamide solutions. The gelling process is described in terms of the storage and loss moduli, G′ and G″, or in terms of the shear wave velocity and the attenuation coefficient. The solutions are quite elastic (G′≈G″) and both moduli increase with gelling. These effects are attributed to hydrogen bonding. The attenuation coefficient decreases abruptly at the onset of gelling. The effective penetration of the shear wave increases from 2.6 µm in solution to 3.4 µm in the gel. The moduli are greatly influenced by the application of a small bias voltage across the gel and this is related to the injection of ions into the shear wave sensing region. Abrupt switching of the bias induces large transient changes in the moduli that are attributed to Lippmann electrocapillary effects at the gel/crystal electrode interface. It is also demonstrated that the crystal produces longitudinal pressure waves, which propagate through the gel and produce secondary resonances. They have a marked effect on the interpretation of the shear wave impedance and can be used to monitor changes in bulk properties through the gelling process.

Amphiphilic particles with hydrophilic core/hydrophobic shell prepared via inverted emulsions

An aqueous solution of acrylamide, its crosslinker (N,N'-methylenebisacrylamide), and an oxidant (ammonium persulfate) was first used to prepare an inverted concentrated emulsion in hexane. Span 80, which is soluble in hexane, was employed as a dispersant. The polymerization of acrylamide in the concentrated emulsion was greatly accelerated by introducing an aqueous solution of a reductant (sodium metabisulfite); it started at room temperature and was completed in a few seconds, resulting in a pastelike product. The system thus obtained was subsequently diluted with hexane containing a hydrophobic monomer. When styrene was used as the hydrophobic monomer, cumene hydroperoxide (which, together with sodium metabisulfite present in the dispersed phase, constitutes the initiator for the polymerization of styrene) was dissolved in the continuous phase. When vinylidene chloride was employed as the hydrophobic monomer, no additional initiator besides sodium metabisulfite and ammonium persulfate already present in the hydrophilic phase had to be employed. The use of initiators which are present only in the hydrophilic phase, and hence also at the interface between this phase and hexane, ensured the polymerization of the hydrophobic monomer as shells that encapsulate the polyacrylamide latexes. Under the proper conditions, a porous outer shell can be generated, which makes the hydrophilic chains present inside accessible. Such hydrophilic core/hydrophobic porous shell particles can be dispersed in water, where they remain stable for a long time, and in hydrophobic liquids, where they remain stable for at least 24 h. For this reason, we call these kinds of particles amphiphilic particles. © 1996 John Wiley & Sons, Inc.

Amphiphilic particles with hydrophilic core/hydrophobic shell prepared via inverted emulsions

An aqueous solution of acrylamide, its crosslinker (N,N'-methylenebisacrylamide), and an oxidant (ammonium persulfate) was first used to prepare an inverted concentrated emulsion in hexane. Span 80, which is soluble in hexane, was employed as a dispersant. The polymerization of acrylamide in the concentrated emulsion was greatly accelerated by introducing an aqueous solution of a reductant (sodium metabisulfite); it started at room temperature and was completed in a few seconds, resulting in a pastelike product. The system thus obtained was subsequently diluted with hexane containing a hydrophobic monomer. When styrene was used as the hydrophobic monomer, cumene hydroperoxide (which, together with sodium metabisulfite present in the dispersed phase, constitutes the initiator for the polymerization of styrene) was dissolved in the continuous phase. When vinylidene chloride was employed as the hydrophobic monomer, no additional initiator besides sodium metabisulfite and ammonium persulfate already present in the hydrophilic phase had to be employed. The use of initiators which are present only in the hydrophilic phase, and hence also at the interface between this phase and hexane, ensured the polymerization of the hydrophobic monomer as shells that encapsulate the polyacrylamide latexes. Under the proper conditions, a porous outer shell can be generated, which makes the hydrophilic chains present inside accessible. Such hydrophilic core/hydrophobic porous shell particles can be dispersed in water, where they remain stable for a long time, and in hydrophobic liquids, where they remain stable for at least 24 h. For this reason, we call these kinds of particles amphiphilic particles. © 1996 John Wiley & Sons, Inc.

Micro-Composites of Poly(styrene) and Nylon 3 by in-situ Polymerization

The in-situ polymerization of acrylamide in solutions of poly(styrene) (PSt) was carried out by anionic polymerization to form Nylon 3 in PSt as micro-composites in which Nylon 3 was dispersed as fine particles. Copolymers of styrene (St) and 4-vinylpyridine (4-VPy) were used as matrix polymers in order to improve a compatibility between the in-situ formed Nylon 3 and matrix polymer through hydrogen-bonding. These micro-composites showed great improvement of mechanical properties owing to reinforcement by ultra-fine particles of Nylon 3. Especially, the micro-composite derived from poly(St-co-4-VPy) showed excellent improvements of mechanical properties owing to the hydrogen bonding interactions between Nylon 3 and 4-VPy.

Electropolymerization of acrylamide at high current density in aqueous media

The flow of high current densities (j > 20 mA cm−2 through aqueous solutions of acrylamide and NaNO3 from platinum electrodes promotes the generation of polyacrylamide. The polymer product remains soluble. The kinetics of the process was followed by gravimetric determination of polymer production. A straightforward polymerization occurs at times longer than 15 min. The empirical kinetics followed through the second region was proportional to [acrylamide]12[NaNO3]−34 and decreases linearly when the current density increases. The activation energy of the overall process was 79 k mol−1. These results, including the variations of the average viscosimetric molar mass of samples, the number of electrons consumed to generate a molecule of polymer and the number of monomeric units incorporated in the polymer per consumed electron, as a function of the chemical variables of synthesis, can be explained through the simultaneous presence of monomer, water and nitrate ion oxidation on the electrode. Gel formation occurs around the electrode for short times of current flow.

Graft polymerization of arcylamide onto LLDPE film by electron beam pre‐irradiation in air or argon. I. Influence of dose, grafting temperature, and monomer concentration

AbstractLinear low density polyethylene (LLDPE) film was irradiated by electron beam in air or argon prior to grafting in aqueous solutions of acrylamide containing 0.05% of Mohr's salt. The grafting kinetics was studied with pre‐irradiation doses in the range of 2.5–25 Mrad and in the temperature range of 40–70°C. Grafting rates and final degrees of grafting were higher for LLDPE pre‐irradiated in air than for LLDPE pre‐irradiated in argon. The overall activation energies for the grafting reaction were dose‐dependent. Above 5 Mrad, the overall activation energies were higher for LLDPE pre‐irradiated in argon which is interpreted as being due to crosslinking of the LLDPE. © 1995 John Wiley & Sons, Inc.

Graft polymerization of acrylamide onto LLDPE film by electron beam pre‐irradiation in air and argon. II. Influence of mohr's salt

AbstractLLDPE film pre‐irradiated by electron beam (EB) in air and argon was grafted in an aqueous acrylamide solution containing Mohr's salt in the concentration range 0.0025–2% The grafting rate and yield were strongly dependent on the Mohr's salt concentration, mainly as a result of chain termination. The exponential grafting rate dependence on the pre‐irradiation dose was quite insensitive to a hundred‐fold variation in Mohr's salt concentration. © 1995 John Wiley & Sons, Inc.

The Effect of Acrylamide and Other Sulfhydryl Alkylators on the Ability of Dynein and Kinesin to Translocate Microtubules in Vitro

Chronic exposure to acrylamide leads to a dying-back axonopathy afflicting the longest axons of all tested mammalian and avian species. Prior to the onset of acrylamide-induced axonal degeneration, alterations in axonal fast transport have been consistently reported to be more severe for the retrograde than the anterograde direction. The putative retrograde motor protein, dynein, is compromised by exposure to the sulfhydryl-alkylating agent N-ethylmaleimide (NEM) at concentrations far below those required to inactivate kinesin, the putative anterograde motor protein. Since acrylamide is capable of alkylating protein sulfhydryl moieties, we tested whether a direct exposure of purified kinesin or dynein to acrylamide would result in an impairment of either enzyme's ability to translocate microtubules. Motor activity was assayed by sequentially adsorbing either kinesin or dynein to acid-washed coverslips, treating with an alkylating agent or control solution, adding microtubules and ATP, and finally imaging and quantifying the binding and gliding of microtubules using video-enhanced differential interference contrast (VE-DIC) microscopy. In comparison to controls, incubation of dynein with NEM, ethacrynic acid, or iodoacetic acid resulted in dose-dependent decreases in the amount and rate of microtubule gliding, but increases in irreversible high-affinity microtubule binding. In contrast, exposure of dynein to 1-100 mM solutions of acrylamide did not significantly alter either the binding or gliding of microtubules (a molar/hour exposure to acrylamide equivalent to 50 times that which causes retrograde transport deficits in vivo). Likewise, kinesin motility parameters were not significantly affected by acrylamide concentrations up to 100 mM while NEM solutions > 100 microM led to significant losses in the ability of kinesin to bind MT. These data indicate that acrylamide does not significantly interact with bound (adsorbed) kinesin or dynein, implying that the mechanism by which acrylamide interferes with fast axonal transport in vivo is by interaction with other factor(s) that govern the movement of vesicles.

Characterization of electropolymerized graphite fiber–polyacrylamide composites

AbstractThe synthesis of a series of graphite fiber‐polyacrylamide composites was performed electrochemically in dilute sulfuric acid (0.125M)‐acrylamide (2M) solution, 1 : 1 sulfuric acid (0.25M) : acetone‐acrylamide (2M) solution, and 1 : 1 sulfuric acid (0.25M) : 2‐propanol‐acrylamide (2M) solution, respectively, using graphite fiber bundles as the working electrode. The graphite fiber‐polyacrylamide composites, synthesized in a 1 : 1 2‐propanol : sulfuric acid‐acrylamide solution, were more easily characterized than those synthesized from the sulfuric acid‐acrylamide solution that contained no alcohol. Composites that were synthesized in a dilute sulfuric acid solution were, however, more readily crosslinked. (Fourier transform infrared spectroscopy, FTIR, confirmed the formation of inter‐chain and intrachain imide functional groups after the resin was cured at ≈ 200°C.) Polymer weight gain analysis, coupled with surface morphology studies using scanning electron microscopy, showed that the thickness of the coatings, and hence the volume fraction of the resin in the composites, varied linearly with the time of electropolymerization. Scanning electron microscopy revealed an open and folded chain surface structure, which permitted unrestricted permeation of the monomer onto the electrode surface. Differential scanning calorimetry of the electropolymerized resins confirmed a glass transition temperature of between 180 and 207°C. © 1994 John Wiley & Sons, Inc.

Gradient polyacrylamide gel electrophoresis in presence of sodium dodecyl sulfate: a practical approach to muscle contractile and regulatory proteins.

Two gradient systems for polyacrylamide gel electrophoresis (PAGE) in the presence of sodium dodecyl sulfate (SDS) are described, with emphasis on improvements accumulated over two decades of studies on contractile proteins and regulatory enzymes from smooth muscle. The first "big slab" system utilizes 18 x 20 x 0.1 cm3 gels and a 10-18% acrylamide gradient, optimized for a high resolution of 10 to 500 kDa polypeptides. Eight (or more) gels are cast simultaneously with a gradient formation from "bottom to top" and 20% glycerol is added to the 18% acrylamide solution. The second "minislab" system represents an improved version of the system of Matsudaira and Burgess (Anal. Biochem. 1978, 87, 386-396), with 8 x 10 x 0.05 cm3 gels and 5-15% or 9-18% acrylamide gradient ranges. They are cast from "top to bottom" in 28-piece batches also with the addition of glycerol for improved gradient formation. Both types of gels can also be cast individually using a specially designed pestle-type gradient maker. For gel destaining, a convenient continuous hydrodynamic destainer is also described.

Bench-scale production of acrylamide using the resting cells of Brevibacterium sp. CH2 in a fed-batch reactor

Effects of various organic acids and salts on the stabilization of nitrile hydratase were investigated. The stability of the nitrile hydratase of Brevibacterium CH2 during storage was greatly enhanced by the addition of n-butyric acid. Effects of temperature, pH, and concentrations of acrylonitrile and n-butyric acid on acrylamide production by the resting cells were also investigated. Acrylamide production per unit dry weight of the cells increased 1.33 times by the addition of 0.05% n-butyric acid. A 20% acrylamide solution was successfully produced in a bench-scale reactor (12 l) with only a trace amount of salts after 10 h of hydration reaction under optimum reaction conditions without using an isotonic substrate. The conversion yield was nearly 100%, and acrylic acid as a by-product was not produced. Final acrylamide production of 400 g g −1 cells and productivity of 20 g/(g cells l −1 · h −1) were obtained.

CO 2-Pulsed laser induced surface grafting of acrylamide onto ethylene-propylene-rubber (EPR)—I

For improved bio and water compatibility laser induced graft copolymerization of acrylamide (AAm) onto the surface of EPR vulcanizates has been attempted using a line-tunable pulsed CO 2 laser. This operates at wavelengths of 9.1–10.6 μm at which EPR is neither ablated nor photodegraded. Grafting has been carried out in 20% aqueous solution of acrylamide. The effectiveness of different photosensitizing systems has been evaluated. The degree of both laser grafting and polymerization of this monomer has been studied. Surface morphology was also investigated by SEM and staining technique. Attenuated Total Reflectance infrared (ATR-IR) and energy dispersive X-ray analysis (EDXA) were performed on the modified samples. Water compatibility (evaluated by measuring water drop contact angle) increase for the modified samples and is found to depend upon surface morphology. Acrylamide is grafted onto EPR by CO 2-laser providing it is irradiated by pulses having wavelengths where acrylamide has strong absorption. Grafting was enhanced by adding sensitizers which have strong absorption band within the working wavelength. The peculiarity of the laser pulsed-induced surface grafting of acrylamide is the formation of fractals. The size and shape of fractals was found to depend upon the exciting wavelength and therefore the degree of excitation of either monomers or photosensitizer (as well as the repetition rate). We believe that infrared laser induced polymerization and grafting of acrylamide with EPR occurs by vibrational excitation of acrylamide or the added photosensitizer through multiphoton absorption mechanism.

Viscometric studies of starch‐g‐polyacrylamide composites

AbstractComposites of starch‐g‐polyacrylamide, starch, and polyacrylamide have been prepared by gamma radiation‐initiated polymerization of acrylamide in the presence of starch in aqueous medium. The polymerization was studied as a function of the (i) amount of water (ii) monomer concentration, and (iii) total dose. The optimum conditions for maximum conversion of the monomer to homopolymer and graft copolymer have been evaluated. Percentage of grafting of polyacrylamide could not be determined precisely as both the homopolymer and the graft are soluble in common solvents and all attempts to separate the graft from the homopolymer were unsuccessful. However, the formation of the starch‐g‐polyacrylamide copolymer was confirmed by the turbidimetric studies using acetone as a nonsolvent. The products of polymerization of acrylamide in the presence of starch consisted of unreacted starch, starch‐g‐polyacrylamide, and polyacrylamide and is referred to as the composite. Acrylamide was also polymerized in the absence of starch using γ‐rays as means of initiation and the optimum conditions for maximum conversion of acrylamide to polyacrylamide have been evaluated. Viscosity behavior of the composite and polyacrylamide was studied in aqueous medium at 30±0.04°C. The reduced specific viscosity of the aqueous solution of acrylamide and the composite as well was found to increase with increasing dilution, the effect being more pronounced in the composite. This tends to indicate that both the homopolymer and the composite behave as polyelectrolytes. An attempt has been made to explain the polyelectrolytic behavior of the homopolymer and the composite. © 1993 John Wiley & Sons, Inc.

Sodium dodecyl sulfate-polyacrylamide solution-filled capillary electrophoresis of proteins using stable linear polyacrylamide-coated capillary.

Sodium dodecyl sulfate (SDS)-linear polyacrylamide solution-filled capillary electrophoresis using a stable coated fused silica capillary has been developed for the separation and molecular weight determination of proteins. A fused silica capillary was coated with linear polyacrylamide through Si-C bond which suppressed the electro-osmotic flow and reduced the adsorption of proteins. Acrylamide solution containing SDS was filled into the coated capillary and polymerized. Compared with a conventional fused silica capillary coated with 3-methacryloxypropyltrimethoxysilane through siloxane linkage (Si-O-Si-C), the developed capillary was much more stable, even in the alkaline condition. Consequently, the durability of the polymer matrices and the reproducibility of separation were markedly improved. An excellent linear relationship was obtained between the mobility and the logarithm of the protein molecular weight. The relative standard deviation of migration times was below 1%.

Two-dimensional gels: An easy method for large quantities of proteins

A new two-dimensional gel technique has been developed that makes it possible to load large amounts of protein and still retain good resolution. Protein samples are added to the isoelectric-focusing acrylamide solution prior to polymerization. Focusing times are short, making it possible to complete both dimensions of a two-dimensional gel in five to six hours. The technique yields larger amounts of separated protein for sequencing, and also greatly increases the quality of two-dimensional immunoblots.

Sodium dodecyl sulfate-capillary gel electrophoresis of proteins using non-cross-linked polyacrylamide

Proteins with relative molecular masses of 14 000 to 205 000 were separated by sodium dodecyl sulfate-capillary gel electrophoresis (SDS-CGE) using non-cross-linked linear polyacrylamide gels on both coated and uncoated fused-silica capillaries. It was determined that viscosity of the acrylamide solution was a major factor affecting column stability with linear acrylamide gels. When the viscosity of the acrylamide solution reaches 100 cP, electro-osmotically driven displacement of the gels is insignificant. Uncoated capillaries provided better resolution, stability, and reproducibility than surface coated capillaries when the concentration of linear polyacrylamide was greater than 4%. At lower gel concentrations, non-cross-linked polyacrylamide is easily displaced from the columns. A calibration plot of log molecular mass vs. mobility with non-linear polyacrylamide was linear, which indicated that resolution was equivalent to that obtained with cross-linked acrylamide. Separations with model proteins indicated that baseline resolution between protein species that vary 10% in molecular mass can be achieved.