Flocculation Properties of Polyelectrolytes Based on 2-(N,N-Dimethyl-N-Benzylammonio)ethyl Methacrylate Chloride

Precipitation of a model kaolin suspension and dehydration of the excess active sludge were studied as influenced by copolymers of 2-(N,N-dimethyl-N-benzylammonio)ethyl methacrylate chloride and its copolymers with acrylamide and 2-(N,N,N-trimethylammonio)ethyl methacrylate methyl sulfate.     

Influence of hydrophobe content and salt concentration on dilute solution behaviour of hydrophobically modified ionic polymers from diallylammonium salts/sulfur dioxide cyclocopolymerization: Light scattering and fluorescence spectroscopy

Novel hydrophobically modified polyelectrolytes were synthesized using the cyclocopolymerization of sulfur dioxide, N,N-diallyl-N-carboethoxymethylammonium chloride and the hydrophobic monomer N,N-diallyl-N-octadecylammonium chloride. Aggregation of these polymers in aqueous solutions was characterized in the dilute regime by static light scattering and fluorescence spectroscopy as a function of hydrophobe content and NaCl concentration. Copolymers were observed to associate at very low concentrations (0.005 wt%). The copolymer is capable of associating at this very low polymer concentration because of the extended length of the hydrophobic monomer (C₁₈) that can reach far enough from the backbone to avoid electrostatic repulsion. Aggregation of the polymers increased with increasing hydrophobe content. Upon addition of salt, the apparent molecular weight of polymer aggregates decreased as a result of neutralization of the charges. At high salt concentrations, the size of the polymer aggregates was observed to increase again as a result of increased polarity of the solvent that resulted in more hydrophobic association.     

Prospects for using the copolymer of N,N-dimethyl-N,N-diallylammonium chloride with acrylamide in production of butadiene-styrene rubber

The flocculating performance of a cationic polyelectrolyte, copolymer of N,N-dimethyl-N,N-diallylammonium chloride with acrylamide, in the recovery of butadiene-styrene rubber from latex was studied in relation to the concentrations of the dispersed phase and acidifying agent and to the temperature.     

Hydrophobically Associating Polymers Dissolved in Seawater for Enhanced Oil Recovery of Bohai Offshore Oilfields

As compared to China’s overall oil reserves, the reserve share of offshore oilfields is rather significant. However, offshore oilfield circumstances for enhanced oil recovery (EOR) include not just severe temperatures and salinity, but also restricted space on offshore platforms. This harsh oil production environment requires polymers with relatively strong salt resistance, solubility, thickening ability, rapid, superior injection capabilities, and anti-shearing ability. As a result, research into polymers with high viscosity and quick solubility is recognized as critical to meeting the criteria of polymer flooding in offshore oil reservoirs. For the above purposes, a novel hydrophobically associating polymer (HAP) was prepared to be used for polymer flooding of Bohai offshore oilfields. The synthetic procedure was free radical polymerization in aqueous solutions starting at 0 °C, using acrylamide (AM), acrylic acid (AA), 2-acrylamido-2-methylpropane sulfonic acid (AMPS), and poly(ethylene glycol) octadecyl methacrylate (POM) as comonomers. It was discovered that under ideal conditions, the molecular weight of HAP exceeds 2.1 × 10⁷ g⋅mol⁻¹. In a simulated reservoir environment, HAP has substantially greater solubility, thickening property, and salt resistance than conventional polyacrylamide (HPAM), with equivalent molecular weight. Finally, the injectivity and propagation of the two polymers in porous media were investigated. Compared with HPAM, which has a similar molecular weight, HAP solution with the concentration of 0.175% had a much better oil displacement effect in the porous medium, which can enhance oil recovery by 8.8%. These discoveries have the potential to pave the way for chemical EOR in offshore oilfields.     

Compositional heterogeneity effects in multisticker associative polyelectrolytes prepared by micellar polymerization

An aqueous micellar radical polymerization technique has been used to prepare water‐soluble polyelectrolytes of acrylamide (AM) and sodium 2‐acrylamido‐2‐methylpropanesulfonate (NaAMPS) hydrophobically modified with low amounts (2–4 mol %) of N,N‐dihexylacrylamide (DiHexAM). This synthesis method leads to multisticker polymers, in which the number and length of the hydrophobic blocks vary with the degree of conversion. Kinetic studies show an appreciable compositional heterogeneity for these polymers, in contrast to their neutral analogues (i.e., AM/DiHexAM copolymers). The drift in composition observed for the AM/NaAMPS/DiHexAM terpolymers is attributed to the electrostatic repulsion between the negatively charged growing polymeric chains, located in the aqueous continuous medium, and the anionic sodium dodecyl sulfate micelles, inside of which the hydrophobic monomer is entrapped. It is shown that an optimization of the polymerization process can be achieved, which gives terpolymers of homogeneous and well‐defined compositions. The thickening ability of the hydrophobically modified polyelectrolytes is directly affected by the extent of their compositional heterogeneity: an increase in the sample homogeneity leads to a significant viscosity enhancement and marked elastic properties of the polymer solutions. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3261–3274, 2003     

Synthesis and aqueous solution properties of hydrophobically modified anionic acrylamide copolymers

In this investigation, hydrophobically modified polyacrylamide with low amounts of anionic long‐chain alkyl was synthesized by the free radical polymerization in deionized water. This water‐soluble copolymerization method is more convenient compared with the traditional micellar copolymerization methods. The copolymers were characterized using Fourier transform infrared, ¹H NMR, and the molecular weight and polydispersity were determined using gel permeation chromatography. The solution behavior of the copolymers was studied as a function of composition, pH, and added electrolytes. As NaCl was added to solutions of AM/C₁₁AM copolymers or pH was lowered, the shielding or elimination of electrostatic repulsions between carboxylate groups of the C₁₁AM unit lead to coil shrinkage. The steady shear viscosity and dynamic shear viscoelastic properties in semidilute, salt‐free aqueous solutions were conducted to examine the concentration effects on copolymers. In addition, the shear superimposed oscillation technique was used to probe the structural changes of the network under various stresses or shear conditions. We prepared hydrophobically modified polyacrylamide with N‐alkyl groups in the aqueous medium. The advantage of this method is that the production is pure without surfactants. These results suggest that the unique aqueous solution behavior of the copolymers is different from conventional hydrophobically associating acrylamide. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 2465–2474, 2008     

Synthesis of 3-(aminooxoethyl)-6-methyl-1-(thiethan-3-yl)-pyrimidine-2,4-(1H,3H)-diones

A new approach to prepare 2-chloroacetamides has been developed, based on the reaction of chloroacetyl chloride with excess of secondary amines. Alkylation of 6-methyl-1-(thiethan-3-yl)pyrimidine-2,4(1H,3H)-dione with the synthesized 2-chloroacetamides in the presence of potassium carbonate has afforded N ³-acetamido-substituted 6-methyl-1-(thiethan-3-yl)pyrimidine-2,4(1H,3H)-diones.     

Coagulation of polystyrene latex in the presence of a cation-active surfactant and polyelectrolytes

Coagulating effect of cation-active polyelectrolytes, a copolymer of N,N-dimethyl-N,N-diallylammonium chloride and maleic acid, a fraction of the homopolymer of N,N-dimethyl-N,N-diallylammonium chloride, and low-molecular cation-active surfactant (1-dodecylpyridinium bromide) on a diluted polystyrene latex at pH 7 and 3 was studied. The presence of macromolecules with different amounts of cation groups in the copolymer accounts for the appearance of several peaks in the curves describing the dependence of a “minute” optical density of the latex synthesized in the presence of a purified surfactant, sulfuric acid monododecyl ester sodium salt, on the copolymer additive.     

The Synthesis of Hydrophobically Modified Water‐Soluble Polyzwitterionic Copolymers and Responsiveness to Surfactants in Aqueous Solution

Abstract

A novel zwitterionic surfactant monomer containing a carboxybetaine moiety and a 10 carbon aliphatic tail was synthesized and copolymerized with acrylamide to yield a water‐soluble, hydrophobically modified zwitterionic polymer [Poly(acrylamide‐co‐(3‐(N,N‐dimethyl‐N‐3′‐(N′‐acryloyl)aza‐tridecyl) ammonio butanoate))]. The response of aqueous polymer solutions to the addition of various classes of surfactant was investigated and compared to that of an analogous novel polymer containing the sulfobetaine zwitterion [Poly(acrylamide‐co‐(N,N‐dimethyl‐N‐3′‐(N′‐acryloyl) aza‐tridecyl) ammonio propane sulfonate))]. It was found that the addition of sodium dodecyl sulfate (SDS) produced a pronounced maximum in viscosity, while dodecyltrimethylammoniumbromide (DTAB), N‐dodecyl‐N,N‐dimethylammonio‐1‐propanesulfonate (SB3‐12), and Triton X‐100 either had no effect, or produced a decrease in viscosity. The effect of pH on polymer–SDS interaction was also studied. Lowering pH increased the SDS–polymer interaction and significantly shifted viscosity enhancement to a higher SDS concentration.     

Synthesis and Characterization of Catechol-Containing Polyacrylamides with Adhesive Properties

In this study, a row of four analogous dopamine acryl- and methacrylamide derivatives, namely N-(3,4-dihydroxyphenyethyl) acrylamide, N-(3,4-dihydroxyphenyethyl) meth acrylamide, N-phenethyl methacrylamide, N-(4-hydroxyphenethyl) methacrylamide were synthesized and characterized by ¹H-NMR and ¹³C-NMR, followed by further solvent-based radical polymerization with N-hydroxyethyl acrylamide. All copolymers were characterized by ¹H-NMR, dynamic differential calorimetry, and gel permeation chromatography. The dependency of the used comonomer ratios to the molecular mass of the corresponding copolymers has been described. The synthesis of the various polymers serves as a feasibility study and provides important data for a future biometric application in the medical field. We synthesized N-(3,4-dihydroxyphenyethyl) acrylamide copolymer up to 80 mol% by free radical polymerization without using any protecting groups. All polymers show identical perfect adhesive properties by a simple scratch test. Further, the monomers were used as a photo reactive glue formulation to test its adherence to a medical titanium surface sample by tensile shear test.     

Fluorocarbon polymerizable surfactants: viscometric behavior, micellar polymerization and interactions with associating polymers

 The micellar aggregation of two fluorocarbon surfactants bearing a polymerizable acrylamido group and differing only in the degree of amido substitution (CONH or CONC₂H₅) has been investigated by viscometry. The two surfactants exhibit distinct solution properties with a micellar growth occurring at a much lower concentration for the N-monosubstituted sample which shows in addition a shear thickening and rheopectic behavior. The ability of the latter surfactant to form hydrogen bonding is responsible for this difference in behavior. Micellar copolymerization of acrylamide with these surfactants or with a hydrocarbon analogue gives copolymers with a polysoap-like behavior. The copolymers in aqueous solution show a pronounced intramolecular hydrophobic aggregation expressed by relatively low-viscosity values when compared with those of other hydrophobically modified water-soluble polymers reported in the literature. Surfactant–polymer mixed systems do not show a strong incompatibility between fluorocarbon and hydrocarbon moieties. Received: 24 March 1998 Accepted: 30 June 1998     

Rheological properties of multisticker associative polyelectrolytes in semidilute aqueous solutions

Multisticker associative polyelectrolytes of acrylamide (≈86 mol %) and sodium 2‐acrylamido‐2‐methylpropanesulfonate (≈12 mol %), hydrophobically modified with N,N‐dihexylacrylamide groups (≈2 mol %), were prepared with a micellar radical polymerization technique. This process led to multiblock polymers in which the length of the hydrophobic blocks could be controlled through variations in the surfactant‐to‐hydrophobe molar ratio, that is, the number of hydrophobes per micelle (N_H). The rheological behavior of aqueous solutions of polymers with the same molecular weight and the same composition but with two different hydrophobic block lengths (N_H = 7 or 3 monomer units per block) was investigated as a function of the polymer concentration with steady‐flow, creep, and oscillatory experiments. The critical concentration at the onset of the viscosity enhancement decreased as the length of the hydrophobic segments in the polymers increased. Also, an increase in the N_H value significantly enhanced the thickening ability of the polymers and affected the structure of the transient network. In the semidilute unentangled regime, the behavior of the polymer with long hydrophobic segments (N_H = 7) was studied in detail. The results were well explained by the sticky Rouse theory of associative polymer dynamics. Finally, the viscosity decreased with an increase in the temperature, mainly because of a lowering of the sample relaxation time. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1640–1655, 2004     

Preparation and solution properties of a novel cationic hydrophobically modified polyacrylamide for enhanced oil recovery

Abstract

A novel cationic water-soluble monomer allyldimethylisooctylammonium bromide (ADIAB) containing a short-chain alkane was synthesized successfully. This monomer was copolymerized with acrylamide and sodium acrylate to produce hydrophobically modified polyacrylamide (HMPAM) using solution polymerization without surfactants. The structures of monomer ADIAB and HMPAM were characterized with infrared spectroscopy and nuclear magnetic resonance spectroscopy. Influence of preparation condition on viscosities of products was studied. The aqueous solution viscosity of the terpolymer was also investigated as functions of concentration, temperature and salinity. The results showed that when the temperature exceeds the 60?°C and NaCl concentration exceeds about 2000?mg/L, the temperature and salt tolerance characters of terpolymer were demonstrated. The enhanced oil recovery tests were initially carried out using homogeneous sandpack models.     

荧光淬灭法研究疏水缔合共聚物(PAM-b-PPOEA)_n自组装聚集数

运用荧光淬灭技术,包括稳态荧光淬灭法(SSFQ)和时间分辨荧光淬灭法(TRFQ),研究了疏水缔合水溶性丙烯酰胺2苯氧基丙烯酸酯多嵌段共聚物[P(AM POEA)]在水溶液中自组装的聚集数.这类聚合物在水溶液中易形成胶束状聚集体,探针芘分子和淬灭剂二苯酮增溶于疏水微区,荧光测定结果很好地符合Poisson淬灭模型.实验结果表明聚合物链结构、聚合物浓度和无机盐对聚集体的尺寸具有重要影响.聚合物自组装聚集数NA随疏水单体含量的增加和疏水嵌段长度的减小而增大,同时也随聚合物浓度和NaCl浓度增加而增大.另外对聚合物链结构、聚集数和溶液粘度的相互关系进行了讨论.     

Synthesis and functional properties of thermosensitive polymer derivatives of proteins

N,N-Diethylacrylamide-N-acryloylphthalimide copolymers have been synthesized. The LCST of the synthesized copolymers decreases with increase in both the molecular mass of the copolymers and the content of more hydrophobic N-acryloylphthalimide units. Through the reaction of the copolymers with the proteinase enzyme inhibitor, ovomucoid, the polymer derivatives of protein have been prepared. It has been shown that the biological activity of ovomucoid and the LCST of polymer derivatives increase with the amount of the immobilized ovomucoid. The effect of biologically active media on the LCST values of polymer derivatives has been studied.     

Copolymerization of acrylic acid amides with alkenyl halides

The binary radical copolymerization of acrylic acid amides (acrylamide and N-cyclohexen-1-ylacrylamide) with alkenyl halides (vinyl chloride, vinyl bromide, and allyl chloride) has been studied. The constants of relative activity of the monomers used are calculated. For the systems under investigation, the occurrence of dehydrochlorination of a polymer chain and protonation of a carbonyl group occur is confirmed. Allyl chloride shows the most pronounced tendency toward dehydrochlorination, while in the case of vinyl chloride, this tendency is the least distinct. The polymer-analogous transformations result in copolymers containing polyene fragments and units of ammonium or oxonium amide salts.     

Copolymerization of N,N-diallyl-N,N-dimethylammonium chloride and vinyl acetate

The free-radical copolymerization of N,N-diallyl-N,N-dimethylammonium chloride with vinyl acetate in DMSO, methanol, and a methanol-water (70: 30, mol %) mixture proceeds to yield statistical copolymers. The nature of solvents significantly affects the reactivity ratios of the comonomers. N,N-Diallyl-N,N-dimethylammonium chloride shows a higher reactivity than vinyl acetate. The kinetic features of the processes have been investigated, and the structure and properties of the copolymers have been studied.     

Water-soluble copolymers containing N-vinylcarbazole

Water-soluble or dispersable copolymers of N-vinylcarbazole (VCbz) with sodium N-acryloylsulfanilate (SAS), or sodium styrene-sulfonate (SSS), or N,N,N-triethyl-N-[2-(methacryloxy) ethyl]-ammonium iodide (TAI), or N,N,N-trimethyl-(p-vinylbenzyl)ammonium chloride (TVBA) were prepared by using a radical initiator. VCbz and SAS were copolymerized in N,N-dimethylacetamide. Copolymers containing more than 49% SAS were water-soluble. In the case of VCbz and SSS, copolymerization was also carried out in DMAN to yield water-soluble copolymers when the SSS content was greater than 36%. VCbz–TAI and VCbz–TVBA were similarly copolymerized in DMAN to give water-soluble polymers when the TAI content was greater than 58% or the TVBA content was 60%. In addition, a copolymer of VCbz and methyl acrylate was partially hydrolyzed with NaOH in tetrahydrofuran to yield a water-dispersable polymer.     

Synthesis of hydrophobically modified poly(acrylamides) in water-in-oil emulsions

High-molecular-mass hydrophobically modified poly(acrylamides) have been prepared via water-in-oil miniemulsion copolymerization of acrylamide and lauryl methacrylate initiated by 2,2′-azoisobutyronitrile. The incorporation of the hydrophobic comonomer into the polymer backbone is indirectly confirmed by the rheological and associative properties of polymer solutions. The copolymers prepared from the reaction mixtures containing less than 5 mol % lauryl methacry late demonstrate the associative behavior in aqueous solutions, as evidenced by fluorescence spectroscopy (a decrease in the polarity parameter of pyrene), static and dynamic light scattering (overestimated effective molecular masses and appearance of a peak due to aggregates), and rheological measurements (a rise of viscosity relative to that of the acrylamide homopolymer). A further increase in the content of lauryl methacrylate leads to formation of polymers possessing limited solubility in water. At the acrylamide-to-hydrophobic monomer equimolar ratio, homopolymers arise along with the insoluble copolymer.     

Synthesis and characterization of hydrophobically modified polyacrylamides and some observations on rheological properties

Hydrophobically modified polyacrylamide (PAM) polymers were synthesized by means of an aqueous micellar copolymerization, the di-alkyl substituted acrylamides di-n-propylacrylamide (DPAM) and di-n-octylacrylamide (DOAM) being used as hydrophobic comonomers. The number of hydrophobic blocks was varied using three different comonomer contents (f=1, 3 and 5 wt.%). The length of hydrophobic blocks, i.e. the number of hydrophobes per micelle, N_H, was controlled by the sodium dodecyl sulphate surfactant concentration. The effect of the type of hydrophobic comonomer and the number and length of hydrophobic units on the composition of the copolymer and its solubility and rheological properties were studied. The results indicate that the average copolymer composition is independent of the degree of conversion and surfactant concentration. Solubility and rheological measurements lead to a number of conclusions. First, DPAM is a weak hydrophobic monomer, all DPAM/AM (AM=acrylamide) copolymers being water soluble. Second, there is no strong hydrophobic interaction between DPAM units, in particular for low polymer concentration and N_H, and thus no strong associative thickening behaviour. Third, DOAM is a strong hydrophobic comonomer. Incorporation of a small amount of DOAM into PAM causes a dramatic enhancement in viscosity due to hydrophobic interactions. The properties of the copolymers are strongly dependent on the N_H values, most DOAM/AM copolymers being insoluble in water.