Acrylamide In Solution Research Articles

Eco-friendly Biodegradable Super Absorbent Polymers (SAPs); An Effective Water Retainer and Agrofertilizer

A polymer is a material which consists of very large molecules, or macromolecules, composed of many repeating subunits. They are classified as synthetic and natural polymers both play essential roles in everyday life due to their broad spectrum of properties. The foremost important class of polymers is superabsorbent polymer (SAP) materials. They are hydrophilic networks which absorb and retain large amounts of water. SAPs are originally divided into two main classes. They are Synthetic (Petrochemical based) and Natural (e.g.; Polysaccharide and Polypeptide based). Most of the present superabsorbent polymers are frequently produced from acrylic acid and acrylamide solution or inverse-suspension polymerization techniques. These are not biodegradable and are harmful to the environment that causes pollution. So, we sought to make biodegradable SAP that can act as a fertilizer to improve the soil quality and water conservation in agricultural land.

A constant shear stress strategy for establishing in situ viscosity models of photoinduced polymerization of acrylamide

AbstractIn situ viscosity kinetics models for blue light induced radical polymerization of acrylamide (AM) were proposed and established with camphorquinone/4‐(dimethylamino)‐2‐ethylbenzoate/diphenyl iodonium hexafluorophosphateas the photoinitiators. In order to minimize the impact of shear effect on polymer network, a constant shear stress technique of photo‐rheometry was proposed to characterize in‐situ viscosity behavior of acrylamide solution during the photopolymerization. The effect of various factors, for example, the dosages of initiator, monomer, and light intensities, on viscosity, polymerization and gelation behavior of AM solution was systematically analyzed. The viscosity advancement behavior was shaped by the joint action of the movement, growth and entanglement of molecular chains, and shear orientation. Different power‐law kinetic models were found in three curves, time‐related viscosity, shear rate‐related viscosity and time‐related shear rate. Such school of thought on constructing the viscosity advancement model provides a new theory and method of systematical studying on the photorheological theories. Furthermore, a trinitarian theoretical model that represented the access from the microscopic kinetics of free radical polymerization to the movement behavior of polymer chains was successfully established by mapping the photoinduced viscosity kinetics model onto the polymerization and crosslinking kinetics model.

Imaging the Gut with "CLARITY".

CLARITY (Clear Lipid-exchanged Acrylamide-hybridized Rigid Imaging compatible Tissue hYdrogel) has recently evolved as a valuable technique involving acrylamide embedding to delipidate tissue (without sectioning) and to preserve the 3-D tissue structure for immunostaining. The technique is highly relevant in imaging the dynamic gut environment where different cell types interact during homeostasis and disease states. This method optimized for the mouse gut is described here, which helps to trace cell types like epithelia, enteroendocrine, neurons, glia, and the neuronal projections into the epithelia or enteroendocrine cells that mediate microbial sensing or nutrient chemo sensing respectively. The gut tissue (1-1.5 cm) is fixed in 4% paraformaldehyde (PFA) in phosphate buffered saline (PBS) at 4 °C overnight on day 1. On day 2, PFA is discarded, and the tissue is washed thrice with PBS. The tissue is hydrogel embedded to preserve its integrity by incubation in 4% hydrogel (acrylamide) solution in PBS (diluted from 30% ProtoGel) overnight at 4 °C. On day 3, the tissue-hydrogel solution is incubated at 37°C for 1 h to allow hydrogel polymerization. Tissue is then washed thrice gently with PBS to remove excess hydrogel. The subsequent step of delipidation (clearing) involves tissue incubation in sodium dodecyl sulfate (8% SDS in PBS) at 37 °C for 2 days (days 4 & 5) on a shaker at room temperature (RT). On day 6, the cleared tissue is thoroughly washed with PBS to remove SDS. Tissue can be immunostained by incubation in primary antibodies (diluted in 0.5% normal donkey serum in PBS containing 0.3% Triton X-100), overnight at 4°C, and subsequent incubation in appropriate secondary Alexa Fluor antibodies for 1.5 h at RT, and nuclear staining with DAPI (1: 10000). The tissue is transferred onto a clean glass slide and mounted using VectaShield for confocal imaging.

Micro flow photochemical synthesis of Ca-sensitive fluorescent sensor particles.

Fluorescence probes have widely been used for detecting and imaging Ca2+‐enriched parts of cells but more rarely for quantitative determination of concentrations. In this study we show how this can be achieved by a novel approach using hydrogel particles. In a microfluidic co‐flow arrangement spherical droplets were generated from an aqueous solution of acrylamide, N,N'‐methylenebisacrylamide crosslinker and photoinitiator and subsequently photo‐cured in situ yielding gel particles in a sub millimeter range. These particles were separated, dried under reduced pressure and re‐swollen in water containing Rhod‐5N tri potassium salt as calcium ion selective fluorescence probe. After that the particles were dried again and stored for further investigations. Upon exposure of dried particles to calcium chloride solutions they swell and take up Ca2+‐ions forming a strong fluorescing complex with Rhod‐5N. Thus, fluorescence intensity increases with calcium ion concentration. Up to ca. 0.50 mM the enhancement effect is strong and then becomes considerably weaker. The intensity‐concentration‐dependence is well described by an equation derived from the equilibrium of the formation of a 1:1 Ca2+:Rhod‐5N complex. The particles allow for a fast optical determination of Ca2+‐concentrations up to 0.50 mM in analyte volumes down to below 10 μL.

The New Approach to the Preparation of Polyacrylamide-Based Hydrogels: Initiation of Polymerization of Acrylamide with 1,3-Dimethylimidazolium (Phosphonooxy-)Oligosulphanide under Drying Aqueous Solutions.

The new initiator of the polymerization of acrylamide, leading to the formation of crosslinked polyacrylamide, was discovered. The structure of the synthesized polyacrylamide was characterized by XRD, 1H NMR, and 13C NMR spectroscopy. It was shown that 1,3-dimethylimidazolium (phosphonooxy-)oligosulphanide is able to initiate radical polymerization under drying aqueous solutions of acrylamide, even at room temperature. According to XRF data, the synthesized polyacrylamide gel contains 0.28 wt% of sulphur. The formed polymer network has a low crosslinking density and a high equilibrium degree of swelling. The swelling rate of polyacrylamide gel in water corresponds to the first order kinetic equation with the rate constant 6.2 × 10−2 min−1. The initiator is promising for combining acrylamide polymerization with the processes of gel molding and drying.

Toxicity of acrylamide after degradation by conjugated (UV/H2O2) photolysis in microalgae.

Acrylamide (AA) is routinely used in laboratories and industries, and its disposal is always a problem; consequently, offering an alternative for their treatment contributes to conducting research in a responsible way. Therefore, in this work, acrylamide solutions were degraded by ultraviolet radiation and hydrogen peroxide (H2O2), and their toxicity was evaluated using a Desmodesmus quadricauda microalgae growth assay. The AA solutions were exposed to different dosages of H2O2 and different exposure times to UV radiation. The degradation was evaluated by liquid chromatography, which allowed the identification of the acrylamide peak and subsequent by-product peaks. A 100% degradation of the 1.5 mg L-1 AA solution with UV/H2O2 (0.034 g L-1) was achieved in just 10 min. The by-products formed did not inhibit the growth of D. quadricauda microalgae. The number of D. quadricauda individuals that grew in acrylamide solutions exposed to 20 and 30 min of UV radiation, with 0.034 g L-1 of H2O2, was very similar to the number of individuals that grew in the control solution. Thus, the treatment proposed in this work using H2O2 combined with ultraviolet radiation degraded acrylamide into by-products with reduced toxicity.

Effects of precipitated size of water-soluble amide-containing polymers and pore size of filters on recovery of Pd nanoparticles dispersed in acetone solution including colloidal polymer

ABSTRACT When immobilized Pd nanoparticles (Pd NP) are used for the hydrogenation of nitrile butadiene rubber (NBR), some Pd NP leaks into the reaction medium. This Pd NP is expensive and must be recovered. In this study, Pd NP were recovered from an NBR acetone medium by precipitation with poly N-[2-(dimethylamino)ethyl] methacrylamide (poly(DAEMA)) and filtration. When poly(DAEMA) solution was added to the Pd NP NBR acetone solution, poly(DAEMA) interacted with Pd NP and formed a precipitate by dehydration. The poly(DAEMA) precipitate including trapped Pd NP was completely recovered by filtration through a filter with a pore size of 1 μm. Poly(acrylamide) solutions of different molecular weights were tested for Pd NP recovery, and those with high molecular weights formed large quantities of precipitates, resulting in low recovery percentages. The concentration and molecular weight of the polymer used for the recovery of Pd NP by nanoprecipitation and filtration must be chosen carefully for optimal recovery. Especially, 40 kDa of PAA and 1 μm filter pores were suitable for efficient Pd NP recovery.

A method of controllable positive-charged modification of PVDF-CTFE membrane surface based on C–Cl active site

There is a great market demand for positive-charged membrane used to treat wastewater containing positive-charged pollutants. Based on the fact that the C–Cl bond energy in the molecular chain of the PVDF-based poly (vinylidene fluoride-co-chlorotrifluoroethylene) (PVDF-CTFE) copolymer membrane is significantly lower than the C–F bond. Herein, the method of controllable positive-charged modification of PVDF-CTFE membrane surface has been successfully realized by using diethylenetriamine (DETA) a small molecule polyamine compound under mild conditions. The modified membranes were characterized by X-ray photoelectron spectroscopy (XPS), zeta potential and water contact angle, and the best condition for positive-charged modification were explored. The results show that the modified membrane has an excellent positively charged effect, changing from an original membrane which is completely negative to the positive-charged membrane whose isoelectric point value is 7.63, the content of N element is as high as 6.31 at% and the water contact angle decreased by 42.8%. After 7 cycles of treatment of polycationic acrylamide solution, the recovery rate of feed-liquid flux is still above 97.5%, indicating that the ability to resist positively charged pollutants is significantly improved. More importantly, the mechanical strength is not adversely affected. The method proposed in this paper may provide a good idea for the graft modification of chlorinated polymers.

ОЧИЩЕННЯ АКРИЛАМІДУ ВІД ІНГІБІТОРІВ ПОЛІМЕРИЗАЦІЇ ДЛЯ ВИГОТОВЛЕННЯ ВИСОКОЯКІСНИХ ФЛОКУЛЯНТІВ НА ОСНОВІ ПОЛІАКРИЛАМІДУ

Polyacrylamide and its copolymers are widely used as flocculating agents for the separation of industrial suspensions. The formation of high molecular weight polymers depends on the content of various impurities present in the monomer. The article presents the scientific and practical information on the production of acrylamide by sulfuric acid method of hydration of nitrile acrylic acid in the form of an aqueous solution of different concentrations and a more modern heterogeneously catalytic method of hydration of acrylonitrile using as catalysts with variable valence. Ways to get different impurities in the stages of production of acrylamide with the purpose of applying appropriate methods for its purification. Laboratory studies of the purification of an aqueous solution of acrylamide from iron ions were carried out as an element of inhibition of the premature polymerization process.

Fluorescence Determination of Acrylamide in Snack, Seasoning, and Refreshment Food Samples with an iOS Gadget–Based Digital Imaging Colorimeter

The novelty of this research work lies in a simple, fast, and plausible analysis of acrylamide in food samples accomplished using an iOS gadgets–based digital imaging colorimeter (iOS gadgets–based DIC). This method is based on fluorescence color measurements obtained from digital images of derivatized acrylamide solution extracted from snack, seasoning, and refreshment food samples (fried banana chip, fried potato chip, fried taro chip, fried durian chip, cayenne pepper, paprika seasoning, tea, and instant coffee). This device represents a convenient and low-cost detection for immediate and simultaneous determination. In addition, there is no reported research using an iOS gadgets–based DIC for the analysis of acrylamide in food samples. In this research, acrylamide is degraded through Hofmann reaction, and a fluorescent product is produced by the vinyl amine reacting with fluorescein, resulting in strong fluorescence emission at 590 nm. Fluorescein was chosen instead of fluorescamine because fluorescein is about 10 times cheaper than fluorescamine. The linear range for the relationship between color value and acrylamide concentration is in the range 1.00–10.0 mg L−1 with the correlation coefficient (R2) of 0.9985. The limits of detection and quantitation were 0.53 and 1.78 mg L−1, respectively. The color values of acrylamide solution were tested for accuracy using food samples spiked with 1.00, 3.00, and 5.00 mg L−1 of standard acrylamide solutions. The recoveries for food samples are in the range 82.74–113.3%. There was no significant difference observed when comparing the results obtained with the DIC instrument with those obtained with fluorescence microplate reader and high-performance liquid chromatography.

Flow analysis of abrasive micro-blasting with glycerol and acrylamideas carrier medium using computational fluid dynamics

Continuous growth is observed in the fieldofNon-Traditional machining where the machiningof newly developing materials is the need of the current segment. Nowadays Abrasive Fluid Jet Machining has used to machine a wide range of elastic and plastic materials including aerospace, automobile, ordinance and combat as well as day to day lifeapplications which require high strength to weight ratios. In Abrasive fluid jet machining, the abrasives are mixed with a liquid to form a slurry. The cutting performance is degraded by the rapid wear of the nozzle by the flow of the Abrasive Fluid mixture through the nozzles that lead to the divergence of the Abrasive Fluid Jet. The Angle of impingement affects the machining responses such that total cutting time has its influence. The Wear characteristics of the Nozzle Material are critical for such machining. The Nozzle inlet pressure of the abrasive fluid jet has a magnanimous effect on the erosion characteristics inside the nozzle. An analysis was carried out with constant Nozzle Taper angle and with Glycerol & Acrylamide solution as a carrier medium. The aim of this work is to analyze the effect of inlet operating pressure on wall shear and exit kinetic energy with respect to glycerol and Acrylamide solution. The two-phase flow analysis was carried by using a computational fluid dynamics tool CFX. The availability of optimized process parameters of abrasive fluid jet machining is limited to water practically. The other Carrier Medium for Abrasive Fluid Jet Machining can be explored widely. In this case, computational fluid dynamics analysis might provide better results than the real-time experimental work.

Vipulanandan p–q model to predict compressive, tensile strengths and swelling of CaSO4 contaminated high plasticity clay modified with polymer

The compressive stress (σ)-strain (e) relationship, tensile strength, and percentage of swelling of contaminated high plasticity clay (CH) soil treated with acrylamide solution (PS) were studied. The CH soil has been contaminated with different amounts of CaSO4 for analysis. The concentration of CaSO4 in the soil was varied from 0 to 4% (0–40,000 ppm) by the weight of dry soil. To characterize the performance of CaSO4 contaminated CH soil, the effect of treating the soil with PS was studied and compared to contaminated CH soil treated with 6% of lime. The soil stabilizer (PS) content was varied by up to 15% (by dry soil weight). With 4% of CaSO4 contaminated CH soils, the compressive and tensile strengths of the CH soil decreased by 51% and 49% respectively. The free swelling [FS (%)] of the CH soil increased from 16% to 23% when the amount of CaSO4 increased from 0 to 4%. X-Ray and TGA techniques examination were done to characterize the mineralogy of the soil due after contamination and treatment. The total weight loss of the contaminated soil with 4% of CaSO4 reduced from 1.34 to 0.33% when the contaminated soil treated with 1.5% of the polymer at the temperature range between 25 and 120 °C. Vipulanandan (p–q) model was used to quantify the compressive stress–strain behavior and percentage of swelling versus time of treated CH soil contaminated with CaSO4.

Temperature Dependence of the Processes of Acrylamide Biodegradation in River Silt Suspensions at Their Inoculation by Selected Bacterial Strains

The temperature dependence of the rate of acrylamide biodegradation by silt microorganisms of small rivers in the Perm krai is studied in the antropogenically polluted Danilikha River, flowing in the territory of Perm city, and the Syuz’va River’s relatively clear tributary in Nytvenskii district. The rate of acrylamide biodegradation increases after introducing into river silt the biomass of bacteria of strains Alcaligenes faecalis 2 and Acinetobacter guillouiae 11h, selected toward an increase in amidase activity. It is shown that, at the ambient temperature of 30°C, the complete degradation of 100 mM acrylamide solution by silt microbiocenosis from the Danilikha River and a tributary of the Syuz’va River has taken place by the 21st and 28th day, respectively, while at 5 and 16–20°C, acrylamide concentration has decreased only slightly even by the 63rd day. The introduction of the biomass of preselected bacteria considerably reduces the time required for complete degradation of acrylamide. At temperature 5°C, acrylamide utilization can take place only at inoculation of silts by the biomass of amidase-containing microorganisms. A mathematical model of acrylamide biodegradation in silt suspensions of small rivers is given; kinetic curves of changes in its concentration are presented, and temperature dependences of biodegradation rates are obtained for different variants of the process.

Rheological Aspects and Extension‐Induced Phase Separation in Electrospinning of Poly(N‐isopropyl acrylamide) Solutions in Dimethylformamide

AbstractSolutions of poly(N‐isopropyl acrylamide) in dimethylformamide are used to study the relation between the rheological properties and electrospinning behavior. Light scattering of electrospinning jet is conducted to obtain the jet diameter at the straight jet end, from which the average extension rate of the jet is derived based on a simple approach. The extension rate is found to be higher than the terminal relaxation rate of polymer chains determined from the dynamic rheological properties. Based on this finding, the original single‐phase polymer solutions may undergo extensional flow‐induced phase separation in the straight jet section during electrospinning. String‐like structures in the liquid jet as well as in the solid fiber are observed by OM, SEM, TEM, and AFM to validate the hypothesis. The inhomogeneity in the jet, due to the presence of dissipative string structures, may serve as the potential precursor to produce lateral perturbations of jet motion to initiate the macroscopic bending instability at the straight jet end for the jet whipping. Moreover, the formation of the beaded fiber, that is, beads‐on‐a‐string structures, is likely relevant with the dissipative structures developed in the jet, besides the Rayleigh instability of the jet arising from surface tension.

On the possibility of using combined polymerization and drying in synthesis of polyacrylamide

This paper presents investigation results of polyacrylamide synthesis with combined polymerization and drying. First, polyacrylamide synthesis was carried out in concentrated aqueous solutions of acrylamide at 30°C. Polymerization was initiated by K2S2O8/Na2S2O3 an oxidation–reduction system. The monomer conversion degree at this stage did not exceed 80%. Further, polymerization with simultaneous solvent elimination from the prepolymer was carried out in a dryer with infrared heat supply and natural convection. Such conditions provide monomer conversion degree up to 100%.

Hydrogen Bonding Aggregation in Acrylamide: Theory and Experiment

Hydrogen bonding plays a role in the microphase separation behavior of many block copolymers, such as those used in lithography, where the stronger interactions due to hydrogen bonding can lead to a smaller period for the self-assembled structures, allowing the production of higher resolution templates. However, current statistical thermodynamic models used in descriptions of microphase separation, such as the Flory–Huggins approach, do not take into account some important properties of hydrogen bonding, such as site specificity and cooperativity. In this combined theoretical and experimental study, a step is taken toward the development of a more complete theory of hydrogen bonding in polymers, using polyacrylamide as a model system. We begin by developing a set of association models to describe hydrogen bonding in amides. Both models with one association constant and two association constants are considered. This theory is used to fit IR spectroscopy data from acrylamide solutions in chloroform, thereby determining the model parameters. We find that models with two constants give better predictions of bond energy in the acrylamide dimer and more realistic asymptotic behavior of the association constants in the limit of high temperatures. At the end of the paper, we briefly discuss the question of the determination of the Flory–Huggins parameter for a diblock copolymer with one self-associating hydrogen bonding block and one non-hydrogen bonding block by means of fitting the scattering function in a disordered state.

Aggregation-Induced Expansion of Poly-(N-isopropyl acrylamide) Solutions Observed Directly by the Transient Grating Imaging Technique.

The anomalous volume expansion of poly-(N-isopropyl acrylamide) (PNIPAM) solutions was observed during the thermally induced polymer phase transition of aqueous solutions having concentrations in the 3–7 wt % range. The process occurred on a millisecond time scale, and a laser temperature-jump time-resolved technique was used to bring about the process. After heating a solution with a pulse laser exploiting light absorption by dyes added to the solution itself, a phase transition was observed to take place, and the temporal changes associated with it were visualized through the transient grating imaging technique, whereby the solution was heated with a stripe pattern. We found several processes occurring on a millisecond time scale, all of which clearly took place after each PNIPAM molecule had collapsed structurally from a coiled to a globular conformation. During the so-called demixing process, the globular polymers aggregated with each other within 10 ms, and suddenly the polymer phase expanded as aggregation progressed further. After this process, the individual globular polymers reverted to their coiled conformation via hydration during the remixing process. We proposed that solution expansion was caused by the mutual entangling of multiple globular PNIPAM molecules, instead each globule polymer was separated.

Assesment of seed quality

A new method for assessing the seed quality of seeds (seed germination) is developed, which involves the germination of seed  material in the cells of a special bed, which is a rectangular block with cells for seeds, made of strong wood or plastic. As a substrate for seed germination, an 8% aqueous solution of acrylamide is used, this is a gel that retains moisture well and replaces moistened sand or filter paper. Using this method makes it possible to increasethe accuracy in calculating the seed rates.

CdS nanodots preparation and crystallization in a polymeric colloidal nanoreactor and their characterizations

Cadmium sulfide (CdS) nanodots in polymeric colloidal reactors were prepared by seeded inverse emulsion polymerization and then crystallized solvothermally. The cadmium sulfate (CdSO4)-polyacrylamide (PAM) seeds were synthesized by inverse miniemulsion polymerization with CdSO4 solution as a co-stabilizer. The prepared CdSO4-PAM particles were used as polymeric colloidal reactors for the formation of CdS-PAM by feeding the mixed solution of sodium sulfide (Na2S) and acrylamide. The effects of the feeding rate on the size, distribution and morphologies of particles were investigated. The influences of the solvothermal treating temperature and time on the crystallite size were characterized. The CdS was well formed and then crystallized in the PAM colloidal reactors. The crystals growth mechanism was taken under consideration. The crystallite size was calculated by the X-ray diffraction (XRD) data, and their morphologies were observed by transmission electron microscopy (TEM). The small CdS crystals showed a blue-shift on the spectra of ultraviolet visible absorption and fluorescence emission. The small CdS crystals displayed the desired property of photocatalytic degradation.

Evolution and disappearance of solvent drops on miscible polymer subphases

Traditionally, an interface is defined as a boundary between immiscible phases. However, previous work has shown that even when two fluids are completely miscible, they maintain a detectable “effective interface” for long times. Miscible interfaces have been studied in various systems of two fluids with a single boundary between them. However, this work has not extended to the three-phase system of a fluid droplet placed on top of a miscible pool. We show that these three-phase systems obey the same wetting conditions as immiscible systems, and that their drop shapes obey the Augmented Young-Laplace Equation. Over time, the miscible interface diffuses and the shape of the drop evolves.We place 2-microliter drops of water atop miscible poly(acrylamide) solutions. The drop is completely wetted by the subphase, and then remains detectable beneath the surface for many minutes. An initial effective interfacial tension can be approximated to be on the order of 0.5 mN/m using the capillary number. Water and poly(acrylamide) are completely miscible in all concentrations, and yet, when viewed from the side, the drop maintains a capillary shape. Study of this behavior is important to the understanding of effective interfaces between miscible polymer phases, which are pervasive in nature.