Articles de revues : « Polymer aqueous solution »

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Panda, Manorama, et Mohammad Kamil. « Polymer-Amphiphile Interactions : An Overview ». Eurasian Chemico-Technological Journal 19, n^o 2 (30 juin 2017) : 99. http://dx.doi.org/10.18321/ectj643.

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Interactions between the polymers and amphiphiles in aqueous solutions have generated considerable interest among researchers because of the widespread applications, relatively complex behavior and improved physicochemical properties of the mixtures. Numerous studies on the surfactant-polymer systems have been carried out in recent years and the number of scientific reports has considerably increased. Various applications of polymers in different areas and many works concerning the amphiphiles are being published every year. Usually, the mixed systems containing polymers and amphiphiles show solution properties different from those of individual solutions due to interaction between the components. The present review article mainly focuses on the behaviour of polymers in aqueous solutions, in the absence or presence of amphiphiles, such as surfactants, drugs, etc. It also summarizes effect of the nature of amphiphiles on aggregation properties of polymers in aqueous solution, and interaction of conventional as well as gemini surfactants with polymers.

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Hu, Xiao Yu, et Ying Bo Chen. « Adsorption Properties of Chemical Crosslinked Polymer Gel ». Advanced Materials Research 87-88 (décembre 2009) : 22–26. http://dx.doi.org/10.4028/www.scientific.net/amr.87-88.22.

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Chemical crosslinker polymer gels were synthesized in situ polymerization of monomers in solvents with crosslinkers. Results showed that the solvent content of the polymer gels depended on the types of solvents and polymers as well as the crosslinkers. The adsorption ability to aromatic organic molecules of the polymer gels was measured by treating tryptophan solution containing phenol and pyrene aqueous solution. The aromatic compounds can be removed completely and no further pollution to the original solutions.

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Kuwahara, Y., Toshiki Miyazaki et Kawashita Masakazu. « Effect of Organic Polymer Addition on the Microstructure of Magnetite-Polymer Hybrid ». Key Engineering Materials 529-530 (novembre 2012) : 453–56. http://dx.doi.org/10.4028/www.scientific.net/kem.529-530.453.

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This study is concerning hybrid materials composed of the magnetite and the organic polymer such as dextran. They are useful for hyperthermia of cancer. In the preparation of this material, chemical structure or molecular weight of the added polymer is expected to affect ionic interaction between polymer and iron salts, and consequently the grain size and morphology of the prepared magnetite core. Therefore, we have synthesized magnetite-polymer hybrids using various polymers. Various polymers were dissolved in iron (II) chloride aqueous solution, and then NaOH aqueous solution was added to this mixed solution. As a result, in the case of neutral and cationic polymer crystalline magnetite was precipitated in the hybrid. On the other hand, in the case of anionic polyacrylic acid, lepidocrocite was precipitated rather than magnetite. It is known that the magnetite formation progresses through intermediate Fe (OH)2 formation and oxidation of the Fe (OH)2 by dissolved O2. Therefore it is considered that tight ionic interaction is constructed between the iron ions and the carboxyl group in the polyacrylic acid to form a complex, and the Fe (OH)2 formation is inhibited. When the hybrid was prepared by addition of NaOH aqueous solution to iron (II) chloride solution, and subsequent addition of the different polymers, magnetite formation was not inhibited irrespective of kind of polymer. The present results indicate that crystalline structure of the magnetite phase in magnetite-polymer hybrid is strongly affected by the chemical structure of polymer additives or the order of addition.

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Asada, Masahiko, Hisakazu Tanaka, Yukie Suwa, Sachiko Irifune, Shigehito Osawa et Hidenori Otsuka. « Tuning Pre-Solution of an Amphiphilic Polymeric Dispersant with Low Acid-Value toward Colored-Ink Preparation ». Applied Sciences 13, n^o 3 (31 janvier 2023) : 1834. http://dx.doi.org/10.3390/app13031834.

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Recently, a variety of amphiphilic block copolymers for water-based color inks as pigment dispersants have been developed. Although such dispersants require both high adsorption of pigments and dispersion-stability in water, the most crucial issue is the difficulty in controlling the affinity balance of the polymeric dispersants between the pigments and aqueous media. Therefore, it is important to increase the solubility of the hydrophobic polymers with low acid-value for ink design. Amphiphilic block copolymers containing styrene-based blocks as hydrophobic segments and methacrylic acid blocks as hydrophilic segments were prepared. The polymers with low acid-value could not dissolve in the alkaline solution directly. They could dissolve in methyl-ethyl-ketone (MEK) at room temperature and diethylene glycol (DEG), with heating. Polymer aqueous solutions were successfully prepared using polymer solutions in DEG as the pre-solutions. Because they were also unable to dissolve directly even in an alkaline solution containing DEG, the existence of DEG is not important, but the process employing the pre-solution is important. The influence of pre-solution viscosity on solubility in water was evaluated. The result suggests that the high viscosity of the DEG solution would work to slowly disperse the polymers in the alkaline solution, efficiently converting polymers into an aqueous soluble state, owing to there being enough time for the neutralization of the carboxylic acids of the polymers. Note that in the pre-solution of a lower concentration, the aqueous solution did not become clear, and the larger particle sizes were detected. These results showed that the viscosity of the pre-solution is an essential factor in solubilization in water. Using this method, the polymeric dispersants with low hydrophilicity were well dissolved in water, up to a high concentration.

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Riaya, Ascencion, Montgomery T. Shaw et Andrew Garton. « Oxidation of Elastomers in Aqueous Environments ». Rubber Chemistry and Technology 67, n^o 5 (1 novembre 1994) : 775–85. http://dx.doi.org/10.5254/1.3538709.

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Abstract Crosslinked 1,4-poly butadiene (BR) and styrene-butadiene rubber (SBR) were oxidized in various ionic environments (water, neutral salt solutions, acidic and basic buffers). The acceleration of oxidation when the elastomer was immersed in neutral and basic aqueous solutions, compared to dry air, is consistent with nucleophilic attack by peroxy anions on polymer hydroperoxides to give free radicals capable of initiating further oxidation. Acidic solutions retarded oxidation, compared to air, presumably because of decomposition of hydroperoxides to nonradical products. This phenomenon is in addition to the well-known effects of extraction of antioxidants by liquid media, and the accelerating effect of transition metal ions. The accelerating effect of basic solutions was greatest at the polymer surface, providing an inexpensive route to surface modification of elastomers. As an example, scrap rubber crumb was treated with aqueous alkaline hydrogen peroxide solution or sodium hypochlorite solution and evaluated as an impact modifier for brittle polymers.

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Kanta Sharker, Komol, Yuki Ohara, Yusuke Shigeta, Shinji Ozoe et Shin-ichi Yusa. « Upper Critical Solution Temperature (UCST) Behavior of Polystyrene-Based Polyampholytes in Aqueous Solution ». Polymers 11, n^o 2 (4 février 2019) : 265. http://dx.doi.org/10.3390/polym11020265.

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Strong polyampholytes comprising cationic vinylbenzyl trimethylammonium chloride (VBTAC) bearing a pendant quaternary ammonium group and anionic sodium p-styrenesulfonate (NaSS) bearing a pendant sulfonate group were prepared via reversible addition-fragmentation chain-transfer polymerization. The resultant polymers are labelled P(VBTAC/NaSS)n, where n indicates the degree of polymerization (n = 20 or 97). The percentage VBTAC content in P(VBTAC/NaSS)n is always about 50 mol%, as revealed by 1H NMR measurements, meaning that P(VBTAC/NaSS)n is a close to stoichiometrically charge-neutralized polymer. Although P(VBTAC/NaSS)n cannot dissolve in pure water at room temperature, the addition of NaCl or heating solubilizes the polymers. Furthermore, P(VBTAC/NaSS)n exhibits upper critical solution temperature (UCST) behavior in aqueous NaCl solutions. The UCST is shifted to higher temperatures by increasing the polymer concentration and molecular weight, and by decreasing the NaCl concentration. The UCST behavior was measured ranging the polymer concentrations from 0.5 to 5.0 g/L.

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Shima, A., T. Tsujino, H. Nanjo et N. Miura. « Cavitation Damage in Polymer Aqueous Solutions ». Journal of Fluids Engineering 107, n^o 1 (1 mars 1985) : 134–38. http://dx.doi.org/10.1115/1.3242431.

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Cavitation damage tests in polymer solutions are made with a vibratory cavitation apparatus. It is possible for this device to suppress the degradation of polymer by ultrasonic cavitation. Polymer solutions used are 100 wppm, 500 wppm, and 1000 wppm solutions of Polyox. The weight loss in 100 wppm Polyox solution is larger than that in water, but in 500 wppm and 1000 wppm Polyox solutions the weight losses after 60 min exposure to cavitation are relatively small. It is indicated that the cavitation damage in polymer solutions is subject to the effective influence of elastic properties of liquids.

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Kancharla, Samhitha, Nathan A. Zoyhofski, Lucas Bufalini, Boris F. Chatelais et Paschalis Alexandridis. « Association between Nonionic Amphiphilic Polymer and Ionic Surfactant in Aqueous Solutions : Effect of Polymer Hydrophobicity and Micellization ». Polymers 12, n^o 8 (15 août 2020) : 1831. http://dx.doi.org/10.3390/polym12081831.

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The interaction in aqueous solutions of surfactants with amphiphilic polymers can be more complex than the surfactant interactions with homopolymers. Interactions between the common ionic surfactant sodium dodecyl sulfate (SDS) and nonionic amphiphilic polymers of the poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) (PEO-PPO-PEO) type have been probed utilizing a variety of experimental techniques. The polymer amphiphiles studied here are Pluronic F127 (EO100PO65EO100) and Pluronic P123 (EO19PO69EO19), having the same length PPO block but different length PEO blocks and, accordingly, very different critical micellization concentrations (CMC). With increasing surfactant concentration in aqueous solutions of fixed polymer content, SDS interacts with unassociated PEO-PPO-PEO molecules to first form SDS-rich SDS/Pluronic assemblies and then free SDS micelles. SDS interacts with micellized PEO-PPO-PEO to form Pluronic-rich SDS/Pluronic assemblies, which upon further increase in surfactant concentration, break down and transition into SDS-rich SDS/Pluronic assemblies, followed by free SDS micelle formation. The SDS-rich SDS/Pluronic assemblies exhibit polyelectrolyte characteristics. The interactions and mode of association between nonionic macromolecular amphiphiles and short-chain ionic amphiphiles are affected by the polymer hydrophobicity and its concentration in the aqueous solution. For example, SDS binds to Pluronic F127 micelles at much lower concentrations (~0.01 mM) when compared to Pluronic P123 micelles (~1 mM). The critical association concentration (CAC) values of SDS in aqueous PEO-PPO-PEO solutions are much lower than CAC in aqueous PEO homopolymer solutions.

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Novoskoltseva, Olga A., Andrey A. Belov, Nataliya G. Loiko, Yury A. Nikolaev, Irina G. Panova et Alexander A. Yaroslavov. « Biodegradable Interpolycomplexes for Anti-Erosion Stabilization of Soil and Sand ». Polymers 14, n^o 24 (8 décembre 2022) : 5383. http://dx.doi.org/10.3390/polym14245383.

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A linear anionic polysaccharide, sodium alginate, electrostatically interacts with a cationic polysaccharide, quaternized hydroxyethyl cellulose ethoxylate, in aqueous solution, thus giving an interpolyelectrolyte complex. Aqueous solutions of the initial polysaccharides and polycomplexes with an excess of the cationic or anionic polymers were used for the stabilization of soil and sand against water erosion. Physicochemical, mechanical and biological properties of the polymers and coatings were characterized by gravimetric analysis, viscosimetry, mechanical strength assessment, cell viability, and cell-mediated degradation with the following main conclusions. (a) Non-stoichiometric polycomplexes with an excess of cationic or anionic units (“cationic” and “anionic” polycomplexes, respectively) form transparent solutions or stable-in-time dispersions. (b) The complexation results in a decrease in the viscosity of polymer solutions. (c) A complete dissociation of polycomplexes to the initial components is achieved in a 0.2 M NaCl solution. (d) Soil/sand treatment with 1 wt% aqueous solutions of polymers or polycomplexes and further drying lead to the formation of strong composite coatings from polymer(s) and soil/sand particles. (e) Cationic polycomplexes form stronger coatings in comparison with anionic polycomplexes. (f) The polymer–soil coatings are stable towards re-watering, while the polymer–sand coatings show a much lower resistance to water. (g) The individual polysaccharides demonstrate a negligible toxicity to Gram-negative and Gram-positive bacteria and yeast. (h) The addition of Bacillus subtilis culture initiates the degradation of the polysaccharides and polycomplexes. (i) Films from polysaccharides and polycomplexes decompose down to small fragments after being in soil for 6 weeks. The results of the work are of importance for constructing water-resistant, low toxicity and biodegradable protective coatings for soil and sand.

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Huang, Hui, Jun Wei Wang, Yi Fan Fan et Shi Ying Tao. « Adsorption Behavior of β-Cyclodextrin Polymer to Phenol in Aqueous Solution ». Advanced Materials Research 554-556 (juillet 2012) : 177–80. http://dx.doi.org/10.4028/www.scientific.net/amr.554-556.177.

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Removal of low concentration of phenol from aqueous solutions through the adsorption process by using crosslinked β-Cyclodextrin polymer (β-CD polymer) was investigated. The effects of contact time, sodium chloride content, contact temperature and initial concentration of phenol in the aqueous on adsorption capacity were evaluated through a series of batch experiments. The results show that β-CD polymer on the adsorption of phenol balanced after 6h. The adsorption process was apparently influenced by sodium chloride content, contact temperature and initial phenol concentration in aqueous solution. The adsorption behavior for phenol of β-CD polymer is fitted into the Freundlich isotherm.

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Sharma, Ramankur, Timothy E. Corcoran, Stephen Garoff, Todd M. Przybycien, Ellen R. Swanson et Robert D. Tilton. « Quasi-Immiscible Spreading of Aqueous Surfactant Solutions on Entangled Aqueous Polymer Solution Subphases ». ACS Applied Materials & ; Interfaces 5, n^o 12 (10 juin 2013) : 5542–49. http://dx.doi.org/10.1021/am400762q.

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Barmar, M., et B. Kaffashi. « Rheological Behavior of HEUR Mixtures in Aqueous Media ». International Polymer Processing 22, n^o 2 (1 avril 2007) : 146–50. http://dx.doi.org/10.1515/ipp-2007-0004.

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Abstract Three S-G HEUR thickeners were synthesized by a step growth polymerization technique of poly (ethylene oxide) (PEO) and dicyclohexylmethane – 4,40-diisocyanate (H12MDI) and then end capped with two monofunctional aliphatic alcohols. These polymers were mixed together according to the hydrophilic and hydrophobic nature of their segments. Based on this, two sets of associating polymers were introduced. In one set, the samples had identical hydrophobic segments while in the other one, hydrophilic segments were similar. The steady shear viscosity profiles of aqueous solutions of all models were determined. In addition, aqueous binary mixtures with various ratios of the S-G HEUR models were studied using steady state and dynamic rheometry. It is suggested that combinations of associating polymers with different size of hydrophobic segments and similar hydrophilic segments produce an associative polymer-like behavior. However, the combination of those with similar long hydrophobic segments and different hydrophilic segments at similar weight ratio in solution falls short of displaying an associative polymer – like behavior.

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Feng, Fa Yong, et Pei Zhi Yu. « Synthesis of Ionic Hydrophobic Associating Polymer and it’s Aqueous Solution‘s Viscosity Characteristics ». Applied Mechanics and Materials 628 (septembre 2014) : 120–24. http://dx.doi.org/10.4028/www.scientific.net/amm.628.120.

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Brief introduction of research progresses of hydrophobically associating water soluble polymer, as well as a synthesis method of a hydrophobically associating water-soluble polymer P (AM/KAA/MAHB). Meanwhile the molecular structure is characterized, and the viscosity behavior of the ionic hydrophobic-associating polymer solution is analyzed. The influences of polymer concentration, temperature, shear rate and water salinity of the saline solution on apparent viscosity are discussed. The critical associating concentration of polymer in salt solutions and salt thickening effect are also studied. The results show that the polymer possesses obvious temperature resistance and salt tolerance compared with partially hydrolyzed polyacrylamide polymer.

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Guzei, Dmitriy, Angelica Skorobogatova, Sofia Ivanova et Andrey Minakov. « A Computational Study of Polymer Solutions Flow Regimes during Oil Recovery from a Fractured Model ». Applied Sciences 13, n^o 20 (20 octobre 2023) : 11508. http://dx.doi.org/10.3390/app132011508.

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Increasing the efficiency of hydrocarbon field development is an important issue. One of the methods for increasing oil recovery is the injection of aqueous solutions of polymers. Although this method has been known and used for quite some time, further systematic research is needed to further improve its effectiveness. In this work, systematic computational studies of the features of oil displacement by aqueous polymer solutions from a naturally fractured structure were carried out. Direct numerical modeling of a two-phase immiscible flow in the process of displacing oil from a natural fracture structure using solutions of anionic polymers based on polyacrylamide was carried out. Aqueous solutions of three different polymers were considered, the concentrations of which varied from 0 to 0.1%, and the molecular weights were from 10 to 20 mln c.u. The rheological properties of polymers and their wetting characteristics have been previously studied in laboratory experiments. A distinctive feature of the polymers considered was the non-Newtonian nature of their aqueous solutions even at low concentrations. To take these processes into account, the computational technique has been extended to the case of non-Newtonian rheology for immiscible two-phase flow in one of the media. During numerical simulations, the effect of the concentration of polymers, their molecular weight, and charging density on the flow regimes in a fractured reservoir have been investigated systematically at various crude oil viscosities. It has been shown that the use of a 0.1% aqueous solution of polyacrymalide can increase the oil-recovery factor by 1.8 times. It has been established that, with an increase in the molecular weight and surface charge density of the polymer, the efficiency of its use for enhancing oil recovery increases. With an increase in the viscosity of the displaced oil, the effect of using the injection of the considered polymers also increases. The data obtained in this work can be used to further improve polymer-flooding technologies for oil fields.

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Ortona, Ornella, Gerardino D'Errico, Luigi Paduano et Roberto Sartorio. « Ionic surfactant–polymer interaction in aqueous solution ». Physical Chemistry Chemical Physics 4, n^o 12 (8 mai 2002) : 2604–11. http://dx.doi.org/10.1039/b111495f.

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Kim, Tae-Hwan, Chaeyeon Song, Young-Soo Han, Jong-Dae Jang et Myung Chul Choi. « Spontaneous unilamellar polymer vesicles in aqueous solution ». Soft Matter 10, n^o 3 (2014) : 484–90. http://dx.doi.org/10.1039/c3sm52519h.

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Bliznyuk, Valery N., Nataliya V. Kutsevol, Yuliia I. Kuziv, Scott M. Husson et Timothy A. DeVol. « Efficient Retention and Alpha Spectroscopy of Actinides from Aqueous Solutions Using a Combination of Water-Soluble Star-like Polymers and Ultrafiltration Membranes ». Polymers 14, n^o 17 (23 août 2022) : 3441. http://dx.doi.org/10.3390/polym14173441.

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We explored two approaches to recover uranium and plutonium from aqueous solutions at pH 4 and pH 7 using water-soluble star-like polyacrylamide polymers with a dextran core. In the first approach, a solution comprising a neutral or ionomer polymer was mixed with a radionuclide solution to form polymer–metal complexes that were then retained by ultrafiltration (UF) membranes under applied pressure. The same polymers were first deposited on the membrane in the second approach using pressure-driven flow. The applied polymers had an overall diameter of gyration of 120 nm, which exceeded the nominal diameter of the UF membrane pores. The polymers showed a high affinity to uranyl but could also be used to extract Pu from neutral or near-neutral pH solutions. Direct-flow single-step filtration and alpha spectrometry demonstrated that the UF membranes containing star-like copolymers could recover 99% of U and up to 60% of Pu from deionized water after filtering 15 mL solutions containing 25 ppm and 33 ppb of the actinides, correspondingly. The sorption capacity of the polymers for uranium could be measured as 1mg U per mg of the polymer after six subsequent filtration steps. Alpha spectroscopy of the deposited actinides revealed peculiarities of the structural organization of polymers and their complexes with U or Pu, depending on the approach. Though both approaches were efficient, the second approach (deposition of the polymer on the membrane followed by filtration) has an additional advantage of protecting the membrane pores from capillary collapse by filling them with the polymer chains. Therefore, these polymer-modified membranes could be used either in continuous or multi-step filtration process with drying after each step without deterioration of their sorption characteristics.

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Abbas, Haider, Muhammad Nadeem, Sumbal Tariq, Tahzeeb Zohra, Imran Ahmad, Tayyaba Munawar, Ashraf Hussain et Sidra Ahmad. « Synergistic Effect of Polypyrrole-Polyaniline Conducting Polymer Nanocomposite and Fe3O4 Nanoparticles for Arsenite (III) Adsorption from wastewater ». Asian Journal of Applied Chemistry Research 14, n^o 3 (6 novembre 2023) : 58–67. http://dx.doi.org/10.9734/ajacr/2023/v14i3271.

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For treatment of arsenic contaminated water, adsorption of arsenic and it’s reduction are there important processes. Conducting polymer efficiently show the efficient absorption but in use of it there is agglomeration of particles which make its usage difficult. To reduce this problem magnetic property material are used. In this polypyrrole and polyaniline conducting polymers were used. By oxidative polymerization of Polypyrrole and aniline in presence of Fe3O4 by utilizing FeCl3 nanocomposite was manufactured. In this magnetite prevented the agglomeration of particles of polymers and also helped in separation of nanocomposite from solution. Characterization was done by FTIR, SEM and XRD. This nanocomposite removal 88% arsenide (III) from aqueous solution at adsorbent concentration 0.01g and pH=1. Colorimetric method was used which developed complex with arsenite (III) and showed the removal of arsenite (III) from aqueous solution by complex. Separation of nanocomposite became easy due to magnetic properties of magnetite. This could be isolate from aqueous solution by using of strong magnet. This nanocomposite is the promising composite for removal of arsenite (III) from aqueous solution.

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Blomberg, Tobias, Nicole Borgmeier, Lars Torben Kramer, Pascal Witzke, Timo Grothe et Andrea Ehrmann. « Influence of Salts on the Spinnability of Poly(Ethylene Glycol) ». Applied Mechanics and Materials 878 (février 2018) : 313–17. http://dx.doi.org/10.4028/www.scientific.net/amm.878.313.

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Electrospinning allows producing nanofiber mats from diverse polymers. In “green electrospinning”, aqueous and other non-hazardous solutions are used as spinning solutions, especially for biopolymers. Physical and chemical material properties of the solutions as well as the nanofiber mats can partly be tailored by co-spinning different materials. Especially for smart textile applications, conductive nanofiber mats are of high interest. However, electrospinning from highly conductive solutions is technically impossible. This article thus investigates the influence of different salts on the conductivity of poly(ethylene glycol) solutions and nanofiber mats and gives an estimate for the maximum possible conductivity of an aqueous polymer solution for electrospinning.

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Lessard, D. G., M. Ousalem et X. X. Zhu. « Effect of the molecular weight on the lower critical solution temperature of poly(N,N-diethylacrylamide) in aqueous solutions ». Canadian Journal of Chemistry 79, n^o 12 (1 décembre 2001) : 1870–74. http://dx.doi.org/10.1139/v01-180.

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The molecular weight dependence of the lower critical solution temperature of poly(N,N-diethylacrylamide) was studied with 11 samples of the polymer with a number-average molecular weight (Mn) ranging from 9.6 × 103 to 1.3 × 106 g mol1 and relatively narrow polydispersity indices from 1.19 and 2.60. These samples were obtained by fractional precipitation of the polymer. LCST values of polymers were measured by turbidimetry and microcalorimetry. An inverse dependence of LCST on the molar mass was found and the LCST of the samples remained more or less a constant above a critical molecular weight of ca. 2 × 105 g mol1. The enthalpy and the entropy changes as well as the LCST of the polymer depend strongly on the molar mass of the polymer, especially in low molecular weight range.Key words: poly(N,N-diethylacrylamide), LCST, thermosensitive, phase diagram, effect of molecular weight.

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Lebouachera, Seif El Islam, Laurence Pessoni, Mohammed Abdelfetah Ghriga, Nathalie Andreu, Rachida Chemini, Bruno Grassl et Stéphanie Reynaud. « Rheological behaviour and adsorption phenomenon of a polymer–particle composite based on hydrolysed polyacrylamide/functionalized poly(styrene-acrylic acid) microspheres ». Soft Matter 15, n^o 27 (2019) : 5449–54. http://dx.doi.org/10.1039/c9sm00844f.

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Onchi, Alejandro, Carlos Corona-García, Arlette A. Santiago, Mohamed Abatal, Tania E. Soto, Ismeli Alfonso et Joel Vargas. « Synthesis and Characterization of Thiol-Functionalized Polynorbornene Dicarboximides for Heavy Metal Adsorption from Aqueous Solution ». Polymers 14, n^o 12 (9 juin 2022) : 2344. http://dx.doi.org/10.3390/polym14122344.

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The contamination of water resources with heavy metals is a very serious concern that demands prompt and effective attention due to the serious health risks caused by these contaminants. The synthesis and ring-opening metathesis polymerization (ROMP) of norbornene dicarboximides bearing thiol pendant groups, specifically, N-4-thiophenyl-exo-norbornene-5,6-dicarboximide (1a), N-4-(methylthio)phenyl-exo-norbornene-5,6-dicarboximide (1b) and N-4-(trifluoromethylthio)phenyl-exo-norbornene-5,6-dicarboximide (1c), as well as their assessment for the removal of heavy metals from aqueous systems, is addressed in this work. The polymers were characterized by NMR, SEM and TGA, among others. Single and multicomponent aqueous solutions of Pb2+, Cd2+ and Ni2+ were employed to perform both kinetic and isothermal adsorption studies taking into account several experimental parameters, for instance, the initial metal concentration, the contact time and the mass of the polymer. In general, the adsorption kinetic data fit the pseudo-second-order model more efficiently, while the adsorption isotherms fit the Freundlich and Langmuir models. The maximum metal uptakes were 53.7 mg/g for Pb2+, 43.8 mg/g for Cd2+ and 29.1 mg/g for Ni2+ in the SH-bearing polymer 2a, 46.4 mg/g for Pb2+, 32.9 mg/g for Cd2+ and 27.1 mg/g for Ni2+ in the SCH3-bearing polymer 2b and 40.3 mg/g for Pb2+, 35.9 mg/g for Cd2+ and 27.8 mg/g for Ni2+ in the SCF3-bearing polymer 2c, correspondingly. The better performance of polymer 2a for the metal uptake was ascribed to the lower steric hindrance and higher hydrophilicity imparted by –SH groups to the polymer. The results show that these thiol-functionalized polymers are effective adsorbents of heavy metal ions from aqueous media.

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Fukumoto, Hirokazu, Kazuhiko Ishihara et Shin-Ichi Yusa. « Thermo-Responsive Behavior of Mixed Aqueous Solution of Hydrophilic Polymer with Pendant Phosphorylcholine Group and Poly(Acrylic Acid) ». Polymers 13, n^o 1 (1 janvier 2021) : 148. http://dx.doi.org/10.3390/polym13010148.

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A mixed aqueous solution of hydrophilic poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) and poly(acrylic acid) (PAAc) becomes cloudy under acidic conditions at room temperature. The pendant carboxylic acid groups in PAAc form hydrogen bonds with the ester and phosphate groups in PMPC. While the polymers aggregate under acidic conditions, neither one associate under basic conditions because of the deprotonation of the pendant carboxy groups in PAAc. We observed that the interpolymer complex formed from PMPC, and PAAc was dissociated in aqueous solutions with increasing temperature, which is an upper critical solution temperature behavior. With increasing temperature, the molecular motion increased to dissociate the interpolymer complex. The phase transition temperature increased with increasing polymer and salt concentrations, and with decreasing pH.

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Bulycheva, Elena G., Natalya M. Belomoina, Roman S. Begunov, Galina G. Nikiforova, Viktor G. Vasil’ev, Radmir V. Gainutdinov, Mikhail Yu Yablokov, Alexander I. Buzin et Mikhail I. Buzin. « One-Step Synthesis of Functional Sulfonated Polynaphthoylenebenzimidazoles for Biosensing Applications ». Applied Sciences 13, n^o 2 (13 janvier 2023) : 1073. http://dx.doi.org/10.3390/app13021073.

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Polynaphthoylenebenzimidazoles containing functional sulfo groups were synthesized by a one-step method in a sulfuric acid medium with oleum. A polymer-analogous transformation of these polymers with aqueous solutions of metal salts (K, Ca, and Cr) was carried out. Their chemical structure was characterized by FTIR, NMR, and elemental analysis. Polymer salt coatings were deposited on QCM sensor surfaces by electron beam-induced vacuum deposition. The morphology of the coatings was characterized by AFM. It was shown that the coatings formed from a series of polymer salts have different adsorption activity in acetaminophen–water solution compared to distilled water. The QCM results indicate that sensor signal correlates with polymer coating thickness, morphology, and its chemical composition.

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Ohsedo, Yutaka, et Wakana Ueno. « Creation of Polymer Hydrogelator/Poly(Vinyl Alcohol) Composite Molecular Hydrogel Materials ». Gels 9, n^o 9 (23 août 2023) : 679. http://dx.doi.org/10.3390/gels9090679.

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Polymer hydrogels, including molecular hydrogels, are expected to become materials for healthcare and medical applications, but there is a need to create new functional molecular gels that can meet the required performance. In this paper, for creating new molecular hydrogel materials, the gel formation behavior and its rheological properties for the molecular gels composed of a polymer hydrogelator, poly(3-sodium sulfo-p-phenylene-terephthalamide) polymer (NaPPDT), and water-soluble polymer with the polar group, poly(vinyl alcohol) (PVA) in various concentrations were examined. Molecular hydrogel composites formed from simple mixtures of NaPPDT aqueous solutions (0.1 wt.%~1.0 wt.%) and PVA aqueous solutions exhibited thixotropic behavior in the relatively low concentration region (0.1 wt.%~1.0 wt.%) and spinnable gel formation in the dense concentration region (4.0 wt.%~8.0 wt.%) with 1.0 wt.% NaPPDT aq., showing a characteristic concentration dependence of mechanical behavior. In contrast, each single-component aqueous solution showed no such gel formation in the concentration range in the present experiments. No gel formation behavior was also observed when mixed with common anionic polymers other than NaPPDT. This improvement in gel-forming ability due to mixing may be due to the increased density of the gel’s network structure composed of hydrogelator and PVA and rigidity owing to NaPPDT.

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Chen, Gui E., De Sun et Zhen Liang Xu. « Rare Earth Ion from Aqueous Solution Removed by Polymer Enhanced Ultrafiltration Process ». Advanced Materials Research 233-235 (mai 2011) : 959–64. http://dx.doi.org/10.4028/www.scientific.net/amr.233-235.959.

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An efficiency of rare earth (europium, Eu) removal from aqueous solutions by polymer enhanced ultrafiltration (PEUF) process was investigated using two water-soluble polymers polyacrylic acid (PAA) and polyethylenimine (PEI). The effects of loading ratios of Eu to PAA or PEI, pH of solution and the added salt on Eu removal were evaluated. It was shown that the binding capacities for PAA and PEI to Eu ions were 0.8g Eu/g PAA and 0.5g Eu/g PEI, respectively. Eu ion rejection R decreased signiﬁcantly at a low pH compared to the results at high pH, regardless of using PAA or PEI. Compared to the PAA case, PEI enhanced UF was more sensitive with changing pH. The effect of the added salt was slightly weak at pH 4-5.At the decomplexation stage, when permeate volume was equal to three times than that of the retentate, Eu removal efficiency (X) of Eu-PAA enhanced UF was 79.5% while that of Eu-PEI enhanced UF was 76.1%, and the polymer PAA and PEI could be recovered more than 97% and 93%, respectively. Eu in the retentate could be extracted effectively and the puriﬁed PAA and PEI solution were obtained. The recovered PAA and PEI solution was same as the fresh PAA and PEI solution in PEUF processes carried out by using the recovery recovered PAA and PEI as complex agents.

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Janderka, Pavel, et Leoš Zábrš. « Electroreduction of a benzenediazonium salt in the presence of a radical acceptor ». Collection of Czechoslovak Chemical Communications 56, n^o 10 (1991) : 2067–72. http://dx.doi.org/10.1135/cccc19912067.

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Potentiostatic reduction of p-methoxybenzenediazoniumtetrafluoroborate was studied in acidic aqueous solutions and in dimethylformamide. The mean number of electrons transferred to a molecule of the depolarizer is influenced by the presence of a radical acceptor, acrylamide, and depends on its concentration. The course of electrolysis in the presence of acrylamide was investigated by measuring the relative viscosity of the electrolysed solution. A polymer was isolated from both aqueous and nonaqueous solutions, and its mean relative molecular mass was determined by viscosimetry in an aqueous solution.

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Schild, Howard G., et David A. Tirrell. « Microcalorimetric detection of lower critical solution temperatures in aqueous polymer solutions ». Journal of Physical Chemistry 94, n^o 10 (mai 1990) : 4352–56. http://dx.doi.org/10.1021/j100373a088.

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Tager, A. A., A. P. Safronov, E. A. Berezyuk et I. Yu Galaev. « Lower critical solution temperature and hydrophobic hydration in aqueous polymer solutions ». Colloid & ; Polymer Science 272, n^o 10 (octobre 1994) : 1234–39. http://dx.doi.org/10.1007/bf00657775.

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Duan, Guo Rong, Xin Wang, Guo Hong Huang et Ying Gong. « Influence of the Structure of Comb-Shaped Polymer on the Adsorption between the Polymer and SO₄^2- Ions ». Key Engineering Materials 480-481 (juin 2011) : 311–16. http://dx.doi.org/10.4028/www.scientific.net/kem.480-481.311.

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Comb-shaped hyper-branched polycarboxylate admixture polymers, both the water-reducing-type JS and slump-retaining-type BT, were prepared, and their adsorption characteristics with SO42- ions were studied by conductivity loss experiments. The results indicated that the adsorptions were related to both the content of carboxylic acid groups in polymers and the concentration of Na2SO4 solution, adsorptive action was formed by the complexation action between the carboxylic acid groups in polymers and SO42- ions, having nothing to do with polyether side chain in polymer. Comb-shaped hyper-branched polymers in aqueous solution would form association super-molecular structure, which could be destroyed by Na2SO4 solution.

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García-Serrano, J., A. M. Herrera et M. Ocampo-Fernández. « Synthesis of Ag Particles Using an Ion-Exchange Polymer with Phosphonic Acid Groups ». Materials Science Forum 691 (juin 2011) : 113–18. http://dx.doi.org/10.4028/www.scientific.net/msf.691.113.

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Ion-exchange polymers find wide applications in fuel cells, electro-organic synthesis, catalysis and nanoparticles synthesis. We report on the use of aqueous solutions of an low molecular weight ion-exchange polymer containing phosphonic acid groups; the poly(p-acryloylaminobenzylphosphonic acid), for the synthesis of Ag particles at room temperature without using additional protective reagent. The process of formation of the Ag particles using the ion-exchange polymer start as an initial complexation of polymer to Ag+, followed by the very slow reduction of the metal ions to the Ag metallic. Our results indicate that this ion-exchange polymer is capable of protect the Ag particles in the solution, permitting us to obtain large-size cubes and rectangular prisms in colloidal solutions which are stable for several months.

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Khutoryanskiy, Vitaliy V. « Synthesis and Solution Properties of Hydrophobically Modified Polysaccharides ». Eurasian Chemico-Technological Journal 7, n^o 2 (13 juillet 2017) : 99. http://dx.doi.org/10.18321/ectj621.

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Hydrophobically modified polymers are amphiphilic macromolecules mainly constituted of a hydrophilic backbone and hydrophobic side groups. In aqueous solutions these polymers undergo inter- or intra-molecular hydrophobic association, which results in unusual properties useful for a number of practical applications. The areas of application of these polymers include associative thickeners for enhanced oil recovery, pharmaceuticals, personal care formulations, coatings, adhesives, surfactants, emulsifiers, etc. This review presents the analysis of a literature data on preparation of hydrophobically modified polysaccharides (HMP) and their properties in aqueous solutions. Some of the synthetic methods used for hydrophobic modification of non-ionic (cellulose ethers, starch, dextran, pullulan, etc.), anionic (carboxymethylcellulose, hyaluronic<br />acid, pectic acid, alginic acid, heparin) and cationic olysaccharides (chitosan) are presented. The methodology used for the investigation of solution properties of hydrophobically modified polysaccharides is discussed. Special attention is paid to aggregate and micelle formation in solutions of hydrophobically<br />modified polysaccharides, solubilization of hydrophobic compounds, their rheological properties and surface activity. The effects of polymer architecture (level of hydrophobic substitution, nature of hydrophobic groups, molecular weight of a hydrophilic backbone, etc.), concentration, temperature, presence of inorganic salts and organic solvents on solution properties of hydrophobically modified polysaccharides are discussed. Some applications of hydrophobically modified polysaccharides are briefly highlighted.

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Sun, Peijian, Yipeng Wang, Song Yang, Xuehui Sun, Bin Peng, Lining Pan, Yunzhen Jia, Xiaobing Zhang et Cong Nie. « Molecularly Imprinted Polymer Nanospheres with Hydrophilic Shells for Efficient Molecular Recognition of Heterocyclic Aromatic Amines in Aqueous Solution ». Molecules 28, n^o 5 (22 février 2023) : 2052. http://dx.doi.org/10.3390/molecules28052052.

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Heterocyclic aromatic amine molecularly imprinted polymer nanospheres with surface-bound dithioester groups (haa-MIP) were firstly synthesized via reversible addition-fragmentation chain transfer (RAFT) precipitation polymerization. Then, a series of core-shell structural heterocyclic aromatic amine molecularly imprinted polymer nanospheres with hydrophilic shells (MIP-HSs) were subsequently prepared by grafting the hydrophilic shells on the surface of haa-MIP via on-particle RAFT polymerization of 2-hydroxyethyl methacrylate (HEMA), itaconic acid (IA), and diethylaminoethyl methacrylate (DEAEMA). The haa-MIP nanospheres showed high affinity and specific recognition toward harmine and its structural analogs in organic solution of acetonitrile, but lost the specific binding ability in aqueous solution. However, after the grafting of the hydrophilic shells on the haa-MIP particles, the surface hydrophilicity and water dispersion stability of the polymer particles of MIP-HSs greatly improved. The binding of harmine by MIP-HSs with hydrophilic shells in aqueous solutions is about two times higher than that of NIP-HSs, showing an efficient molecular recognition of heterocyclic aromatic amines in aqueous solution. The effect of hydrophilic shell structure on the molecular recognition property of MIP-HSs was further compared. MIP-PIA with carboxyl groups containing hydrophilic shells showed the highest selective molecular recognition ability to heterocyclic aromatic amines in aqueous solution.

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Khmelnitskiy, I. K., V. M. Aivazyan, N. I. Alekseyev, A. P. Broyko, V. V. Luchinin et D. O. Testov. « Investigation of Ionic EAP Actuators with Metal and Polymer Electrodes in Aqueous Medium ». Nano- i Mikrosistemnaya Tehnika 23, n^o 1 (24 février 2021) : 32–43. http://dx.doi.org/10.17587/nmst.23.32-43.

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Electroactive polymers (EAP) are promising materials for creating electromechanical transducers. Among ionic EAP, ionic polymer-metal composites (IPMC), which are an ion-exchange membrane with metal electrodes on both sides, have been widely spread and well studied. The evolutionary development of IPMC results in ionic polymer-polymer composites (IP2C), in which polymer electrodes are used. To obtain IPMC actuators with platinum electrodes, the method of chemical reduction from the salt solution was chosen, and to obtain IP2C actuators with PEDOT electrodes, the method of in situ polymerization of the monomer on the membrane surface was chosen. Samples of 2x0.5 cm in size based on the MF-4SK membrane with a thickness of 290 μm were preliminarily kept in deionized water (H+ form) and in 0.1 M CuSO4 aqueous solution (Cu2+ form), after which their performance was studied in air, in deionized water, as well as in aqueous solutions of CuSO4 and NaCl. When applying a DC voltage and a sine wave AC voltage, a decrease in the maximum displacement and peak-to-peak displacement of the IPMC actuators and IP2C actuators with an increase in the ionic strength of the liquid was observed, except for the case of the IPMC actuator operation in CuSO4 aqueous solutions. In all considered media, the IPMC actuators and IP2C actuators in Cu2+ form displaced more strongly than the corresponding samples in H+ form, except for the IP2C actuators in deionized water. The largest peak-to-peak displacement was demonstrated by the IPMC actuators in Cu2+form when operating in air (5 mm) and the IP2С actuators in H+ form when operating in deionized water (8.4 mm).

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Otulakowski, Łukasz, Maciej Kasprów, Aleksandra Strzelecka, Andrzej Dworak et Barbara Trzebicka. « Thermal Behaviour of Common Thermoresponsive Polymers in Phosphate Buffer and in Its Salt Solutions ». Polymers 13, n^o 1 (28 décembre 2020) : 90. http://dx.doi.org/10.3390/polym13010090.

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Thermoresponsive polymers are a promising material for drug nanocarrier preparation, which makes the study of their aggregation in physiological conditions very important. In this paper, the thermal behaviour of the thermoresponsive polymers poly(N-isopropylacrylamide), poly(2-isopropyl-2-oxazoline-co-2-n-propyl-2-oxazoline) and poly[(2-hydroxyethyl methacrylate)-co-oligo(ethylene glycol) methyl ether methacrylate] were studied in phosphate buffer (PBS) and solutions of its salts in concentration as in PBS. The thermal response of the polymers was measured using UV-Vis and dynamic light scattering (DLS). The salts shifted the cloud point temperature (TCP) of the (co)polymers to higher values compared to the TCP of aqueous polymer solutions. In PBS and NaCl solutions, all polymers exhibited an unexpected and previously unreported transmittance profile. During heating, an additional aggregation of polymers appeared above the TCP accompanied by the formation of a precipitate. In monosodium phosphate solutions and pure water, the studied polymers showed lower critical solution temperature (LCST-type) behaviour. DLS measurements showed that a salt influenced the size of the resulting polymer particles. The sizes and stability of particles depended on the heating rate. In PBS and NaCl solutions, the size of particles in the dispersion decreased above 60 °C, and the precipitate appeared on the bottom of the cuvette. The additional aggregation of polymer and its falling out of solution may hinder the removal of carriers from the body and has to be taken into account when preparing nanocarriers.

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Asadova, A. H., et E. A. Masimov. « The solution-gel phase transition in aqueous solutions of agarose ». Modern Physics Letters B 35, n^o 08 (18 janvier 2021) : 2150147. http://dx.doi.org/10.1142/s0217984921501475.

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Thermal hysteresis and stability of agarose–water gelling systems were studied by the spectrophotometer for different concentrations at different temperatures. Gelation temperature depends on the concentration of agarose. With the increase in the concentration of agarose gelation temperature, strength of agarose increases too. With the increase in the concentration of polymer solvent–gel phase transition, gel melting happens at higher temperatures. The price of enthalpy was determined (150.0127 KC/mol). In gelation process, the phase separation is completed and in this process, the value of this [Formula: see text] equally increases.

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Turbin, Mikhail V. « Research of a mathematical model of low-concentrated aqueous polymer solutions ». Abstract and Applied Analysis 2006 (2006) : 1–27. http://dx.doi.org/10.1155/aaa/2006/12497.

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The initial-boundary value problem for the mathematical model of low-concentrated aqueous polymer solutions is considered. For this initial-boundary value problem a concept of a weak solution is introduced and the existence theorem for such solutions is proved.

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Uznanski, P., J. Pecherz et M. Kryszewski. « Photophysical studies of hydrophobically functionalized polyionene systems in aqueous solutions ». Canadian Journal of Chemistry 73, n^o 11 (1 novembre 1995) : 2041–46. http://dx.doi.org/10.1139/v95-252.

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Complexes of polyionene and anionic dyes and surfactant were prepared by exchange reaction of counterions in the parent polymer. Fluorescence studies were conducted to observe some characteristic behaviour of these complexes in water Polyionenes with aromatic hydrocarbons adopt an open conformation and there is no evidence for interpolymer interactions. On the contrary, polyionenes with long aliphatic counterions easily form microdomains in aqueous solution due to hydrophobic interaction as evidenced by an increase in excimer emission. Microdomains have an interpolymer nature, as confirmed by measurements of energy transfer from naphthalene to pyrene moieties. Polyionenes with SDS counterions interact with external surfactant molecules and form polymer–surfactant aggregates. Electrostatic repulsions between aggregates dominate on hydrophobic interaction between polymer chains and are responsible for conformational changes. Keywords: hydrophobically modified polymers, surfactants, complexation, fluorescence, nonradiative energy transfer

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Sen, Sobhan, Dipankar Sukul, Partha Dutta et Kankan Bhattacharyya. « Solvation Dynamics in Aqueous Polymer Solution and in Polymer−Surfactant Aggregate ». Journal of Physical Chemistry B 106, n^o 15 (avril 2002) : 3763–69. http://dx.doi.org/10.1021/jp0118672.

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Minagawa, Keiji, Genki Shiizaki, Yukihiro Arakawa, Yasushi Imada et Masami Tanaka. « Controlled Physical Gelation of Thermoresponsive Poly(2-propionamidoacrylic acid) Aqueous Solution ». Advanced Materials Research 1110 (juin 2015) : 96–99. http://dx.doi.org/10.4028/www.scientific.net/amr.1110.96.

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The thermoresponsive properties of aqueous poly (2-propionamidoacrylic acid) (PPA) solutions were studied in the presence of calcium chloride (CaCl2). The turbidity and viscosity of a PPA solution depended on temperature and concentration of the polymer and salt added. For example, a transparent PPA solution changed to a turbid gel at a temperature higher than the cloud point in the presence of a relatively high concentration of CaCl2. The mechanism of physical gelation was considered by comparing the thermoresponsive properties between PAA and a more hydrophilic polymer, poly (acetamidoacrylic acid) (P4A), which has similar structure to that of PPA. In the case of P4A, physical gelation was not observed under similar conditions to those at PPA gelation. This result indicates that hydrophobic interaction among the alkyl groups at one of the polymer side-chains is necessary for the gelation. Dynamic viscoelasticity measurements of these aqueous polymer solutions by use of a rotation rheometer gave quantitative data such as the complex viscosity and the storage and loss moduli, which strongly depended on the solution composition. It is concluded that both hydrophobic interaction among alkyl groups and ionic crosslinking by calcium ion play an important role for the gelation. The drastic change in the rheological property indicates that the sol-gel transition of PPA solution can be successfully controlled by adjusting the temperature and concentration of each component. The controllable rheological property is expected to be useful for various applications, especially in the biomedical field.

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Chibowski, S., M. Paszkiewicz et M. Wiśniewska. « The Influence of Surfactant (SDS) on the Adsorption Properties of Polyvinyl Alcohol and Polyethylene Glycol in an Alumina/Solution System ». Adsorption Science & ; Technology 20, n^o 6 (juillet 2002) : 573–82. http://dx.doi.org/10.1260/026361702321039500.

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The influence of sodium dodecyl sulphate (SDS) on the adsorption properties of non-ionic polymers, i.e. polyethylene glycol (PEG) and polyvinyl alcohol (PVA), at the Al2O3/solution interface was studied. Measurements for various molecular weights and for various amounts of functional groups on the polymer macromolecules were undertaken and the results obtained discussed in the light of these variations. Studies of the mutual interactions of the polymer–surfactant system in aqueous solution were helpful in explaining the equilibria involved in the Al2O3/polymer solution system in the presence of SDS. The thickness of the adsorption layer was determined by viscometric methods and the influence of the degree of hydrolysis of PVA on the structure of the adsorption layer demonstrated.

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Patta, Y. R., D. E. Wesolowski et M. J. Cima. « Aqueous polymer–nitrate solution deposition of YBCO films ». Physica C : Superconductivity 469, n^o 4 (février 2009) : 129–34. http://dx.doi.org/10.1016/j.physc.2008.12.006.

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Azman, N. A. A., A. Amohd Azoddein et M. F. Ali. « Polymer sorbent for mercury removal from aqueous solution ». IOP Conference Series : Materials Science and Engineering 736 (5 mars 2020) : 052020. http://dx.doi.org/10.1088/1757-899x/736/5/052020.

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Ashaduzzaman, Md, Shu Hei Kai et Masashi Kunitake. « Investigation of Click Reaction at an Oil-Water Interface Using Hydrophobic and Hydrophilic Polymers ». International Letters of Chemistry, Physics and Astronomy 11 (septembre 2013) : 31–39. http://dx.doi.org/10.18052/www.scipress.com/ilcpa.11.31.

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Cu(I)-catalyzed Huisgen click reactions between lipophilic polymer (tri-arm azidofunctionalized polystyrene) and hydrophilic polymer (copolymer of styrene sulfonate sodium and propargyl methacrylate) were investigated and hollow capsules, consisting of composite polymer nanofilms were obtained in chloroform-water biphasic solution. Since the lipophilic polymer, or hydrophilic polymer and copper catalyst were present in the oil or aqueous phase, respectively, the cross-linking reaction proceeded only at the phase interface. The combination of lipophilic and hydrophilic polymers produced hollow capsules consisting of nanofilms with lipophilic core and hydrophilic shell.

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Ashaduzzaman, Md, Shu Hei Kai et Masashi Kunitake. « Investigation of Click Reaction at an Oil-Water Interface Using Hydrophobic and Hydrophilic Polymers ». International Letters of Chemistry, Physics and Astronomy 11 (2 avril 2013) : 31–39. http://dx.doi.org/10.56431/p-96v5at.

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Cu(I)-catalyzed Huisgen click reactions between lipophilic polymer (tri-arm azidofunctionalized polystyrene) and hydrophilic polymer (copolymer of styrene sulfonate sodium and propargyl methacrylate) were investigated and hollow capsules, consisting of composite polymer nanofilms were obtained in chloroform-water biphasic solution. Since the lipophilic polymer, or hydrophilic polymer and copper catalyst were present in the oil or aqueous phase, respectively, the cross-linking reaction proceeded only at the phase interface. The combination of lipophilic and hydrophilic polymers produced hollow capsules consisting of nanofilms with lipophilic core and hydrophilic shell.

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Zhao, Jie, Xiangqiang Pan, Jian Zhu et Xiulin Zhu. « Novel AIEgen-Functionalized Diselenide-Crosslinked Polymer Gels as Fluorescent Probes and Drug Release Carriers ». Polymers 12, n^o 3 (3 mars 2020) : 551. http://dx.doi.org/10.3390/polym12030551.

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Stimuli-responsive functional gels have shown significant potential for application in biosensing and drug release systems. In this study, aggregation-induced emission luminogen (AIEgen)-functionalized, diselenide-crosslinked polymer gels were synthesized via free radical copolymerization. A series of polymer gels with different crosslink densities or tetraphenylethylene (TPE) contents were synthesized. The diselenide crosslinker in the gels could be fragmented in the presence of H2O2 or dithiothreitol (DTT) due to its redox-responsive property. Thus, the TPE-containing polymer chains were released into the aqueous solution. As a result, the aqueous solution exhibited enhanced fluorescence emission due to the strong hydrophobicity of TPE. The degradation of polymer gels and fluorescence enhancement in an aqueous solution under different H2O2 or DTT concentrations were studied. Furthermore, the polymer gels could be used as drug carriers, suggesting a visual drug release process under the action of external redox agents. The AIEgen-functionalized, diselenide-crosslinked polymer gels hold great potential in the biomedical area for biosensing and controlled drug delivery.

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Ebrahimi, Rajabali, Giti Tarhande et Saeed Rafiei. « The Study of Ultrasonic Degradation of Superabsorbent Hydrogels ». Organic Chemistry International 2012 (15 octobre 2012) : 1–5. http://dx.doi.org/10.1155/2012/343768.

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Viscometry is a valid and practical approach for monitoring the degradation of polymers in solution. In this work, at constant power and pulse, the effects of different operating parameters such as time of irradiation, temperature, solution concentration, volume, solvent, and immersion depth of horn on the rate of degradation have been investigated in aqueous solution using laboratory scale operation. A method of viscometry was used to study the degradation behavior of aqueous dispersions of microgels. The experimental results show that the viscosity of polymer solution decreased with an increase in the ultrasonic irradiation time and approached a limiting value. The present work has enabled us to understand the role of the different operating parameters in deciding the extent of viscosity reduction in aqueous dispersions of microgels and also the controlling effects of them.

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Suzuki, Noriyuki, Daisuke Mizuno, Armando M. Guidote, Shun Koyama, Yoshiro Masuyama et Masahiro Rikukawa. « Asymmetric Reactions in Water Catalyzed by L-Proline Tethered on Thermoresponsive Ionic Copolymers ». Letters in Organic Chemistry 17, n^o 9 (17 septembre 2020) : 717–25. http://dx.doi.org/10.2174/1570178616666190819141307.

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L-Proline was covalently tethered on thermoresponsive ionic block copolymers that formed micelles in aqueous solutions. The block copolymers consisted of a poly(N-isopropylacrylamide) (PNIPAAm) segment and an anionic or cationic polymer segment. These copolymers exhibited lower critical solution temperature (LCST) behavior at ca. 35-40°C, and achieved thermal stimuli-induced formation and dissociation of micelles. The copolymer generated micelles in aqueous solution at a higher temperature, where a catalytic aldol reaction proceeded with high diastereo- and enantioselectivities. The micelles dissociated at lower temperature to form a clear solution such that the products could be efficiently extracted from the aqueous reaction mixture. Extraction of the aldol product with an organic solvent from the aqueous solution of the anionic copolymer was more efficient than from the nonionic copolymer solution.

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Ding, Yuan Rong, Zhi Wei Li, He Qun Su et Yang Ding. « Study on Viscosity of Poly(Acrylic Acid-Co-Acrylamide) Concentrated Solution with Different Potential Crosslinking Agent ». Advanced Materials Research 311-313 (août 2011) : 1157–60. http://dx.doi.org/10.4028/www.scientific.net/amr.311-313.1157.

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Poly(acrylic acid-co-acrylamide) has large number of ionic and nonionic hydrophilic groups, such making the rheological behavior of its solution complex. In this research, four different potential crosslinking agents which contains activating hydroxyl group and unsaturated bond were introduced into the poly(acrylic acid-co-acrylamide) polymer during aqueous solution radical polymerizations. Rotary viscosimeter was chosen to characterize the apparent viscosity of poly(acrylic acid-co-acrylamide) concentrated solutions. Temperature, concentration of the aqueous concentrated solutions and proportion of potential crosslinking agent are the most important factors. Results shows that the apparent viscosity of PAAM concentrated solution decreases with the increase of temperature, the decreases of concentration of the aqueous concentrated solutions and the proportion of potential crosslinking agent.

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Bassett, David C., Armend G. Håti, Thor B. Melø, Bjørn T. Stokke et Pawel Sikorski. « Competitive ligand exchange of crosslinking ions for ionotropic hydrogel formation ». Journal of Materials Chemistry B 4, n^o 37 (2016) : 6175–82. http://dx.doi.org/10.1039/c6tb01812b.

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We describe a new approach to form hydrogels of ionotropic polymers using competitive displacement of chelated ions. This strategy enables control of ion release kinetics within an aqueous polymer solution and thus control over gelation kinetics across a wide range of pH.

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