Solution properties and flocculation of hydrophobically associating cationic fluorinated polyacrylamide

The hydrophobically associating cationic fluorinated polyacrylamide (CFPAM), modified with fluorinated acrylate, 2-(perfluorooctyl)ethyl acrylate (FEA), has been newly synthesized, by free radical micellar copolymerization in aqueous solution. The solution properties of these polymers were investigated in details in this study. In addition, the flocculation of CFPAM was also evaluated. The results showed that there were strong hydrophobic associations in the CFPAM aqueous solution. The addition of NaCl resulted in an increase of solution viscosity, which indicated the good salt-resistant performance of CFPAM. The polymers also exhibited excellent property of temperature and shearing tolerance. Furthermore, the polymer showed high surface activity. At the same time, its flocculation properties were evaluated with kaolin suspensions using a standard jar test. All the results demonstrated the superiority of the cationic fluorinated polyacrylamide as a flocculant.     

Intrinsic viscosity, surface activity, and flocculation of cationic polyacrylamide modified with fluorinated acrylate

A novel cationic polyacrylamide modified with fluorinated acrylate had been synthesized of acrylamide (AM), methacryloxyethyl trimethylammonium chloride (DMC), and 2-(perfluorooctyl)ethyl acrylate (FEA) by free radical micellar copolymerization in aqueous solution utilizing cetyl trimethylammonium bromide (CTAB) as the surfactant and potassium persulfate (KPS)/sodium bisulfite (SBS) as the redox initiator. Some factors affecting synthesis, such as the amount of FEA, CTAB, and KPS, were described. Surface activity and flocculation of the polymer were studied. The results showed that with the incorporation of FEA, the intrinsic viscosity decreased until the modified polymer was not able to dissolve in water; and with the increase of CTAB and KPS, the intrinsic viscosity decreased firstly then increased slowly. The polymer exhibited good surface activity in both water and salt solution. Its flocculation properties were evaluated with kaolin suspensions using a standard jar test. The results demonstrated the superiority of the copolymer over the no-modified cationic polyacrylamide as a flocculant.     

表面活性剂对孪尾缔合聚合物水溶液表观黏度的影响

用黏度法研究了孪尾疏水缔合水溶性聚合物聚（丙烯酰胺／丙烯酸钠／N,N-二己基丙烯酰胺）[P（AM／NaAA／DiC6AM）]与十二烷基硫酸钠（SDS）、十六烷基三甲基溴化铵（CRAB）、OP-10的相互作用。结果表明,水溶液的表观黏度随SDS、CTAB质量浓度的增加急剧上升,超过一定浓度后水溶液黏度又急剧下降;黏度上升的幅度随疏水单体用量的增加、表面活性剂与疏水单体的摩尔比率（SMR值）的减小而增大;随水解度的增加,黏度上升的幅度较小。P（AM／NaAA／DiC6AM）的临界缔合浓度cac约为30g/mL,当加入SDS、CTAB时,能显著地降低。随OP-10质量浓度的增加,水溶液表观黏度几乎不变。表明P（AM／NaAA／DRAM）与SDS、CTAB的疏水缔合作用较强,而与OP-10的疏水缔合作用较弱。     

Solution behavior of two novel anionic polyacrylamide copolymers hydrophobically modified with n‐benzyl‐n‐octylacrylamide

Two novel hydrophobically modified anionic polyacrylamides (HM‐PAMs), p(AM/NaA/NaAMC₁₂S/BOAM) and p(AM/NaA/OP‐10‐AC/BOAM) have been prepared by an aqueous micellar copolymerization technique from acrylamide, sodium acrylate (NaA), sodium 2‐(acrylamido)dodecane‐1‐sulfonate (NaAMC₁₂S), octylphenol polyoxyethylene acrylate (OP‐10‐AC), and small amounts of N‐benzyl‐N‐octylacrylamide, respectively, with the objective of investigating the copolymers' rheological behaviors and surface activities under various conditions such as polymer concentration, shear rate, temperature, and salinity. As expected, the copolymers exhibit improved thickening properties due to intermolecular hydrophobic associations as the solution viscosity of the copolymers increases sharply with increasing polymer concentration. A decrease in viscosity is observed with increasing temperature, and the solution viscosity of the copolymers decreases with increasing NaCl concentration. Furthermore, the block copolymers exhibit high air–liquid surface activities as the surface tensions (STs) decrease with increasing polymer concentration. This behavior is yet another evidence of polymolecular micelles formation of the copolymers in aqueous solution, and thus the high tendency to adsorb at an interface. The ST exhibited by the copolymers was found to be relatively insensitive to the concentration of salt (NaCl). Scanning electron micrographs showed large aggregates in solutions, which is formed by the association from the hydrophobic groups of the polymers. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers     

表面活性剂对疏水改性丙烯酰胺共聚物增粘性能的影响

采用自由基胶束聚合法合成丙烯酰胺/丁基苯乙烯疏水缔合水溶性共聚物(PSAM),所用的十二烷基硫酸钠(SDS)、辛基酚聚氧乙烯醚(OP-10)和十六烷基三甲基溴化铵(CTAB)能显著影响疏水单体在聚合产物中的含量,从而影响聚合物的溶液粘度,其中以SDS合成得到的产物的溶解性及增粘性能最好。另外,少量表面活性剂的加入能显著地提高聚合物亚浓溶液的粘度,在十二烷基苯磺酸钠(SDBS)、SDS和CTAB中,SDBS对聚合物亚浓溶液粘度的影响最大,其浓度为0.7 mmol/L时,0.3 g/dL PSAM溶液的表观粘度从237 mPa.s上升到981 mPa.s。     

新型孪尾疏水改性聚合物／表面活性剂的溶液性能研究

采用前加碱胶束共聚-共水解法制备了丙烯酰胺、丙烯酸钠和新型孪尾疏水单体N,N-二正辛基丙烯酰胺的三元共聚物P(AM/NaAA/DiC8AM),利用FTIR和1H-NMR确定了共聚物的结构,测定了共聚物/表面活性剂复合体系水溶液的表观粘度,研究了表面活性剂种类、温度、电解质、剪切速率等因素对复合体系溶液表观粘度的影响。P(AM/NaAA/DiC8AM)/SDS和P(AM/NaAA/DiC8AM)/CTAB复合体系的溶液表观粘度与HPAM共聚物溶液相比有明显的提高,疏水单体含量越大,复合体系的溶液表观粘度越大,且其溶液具有一定的耐温、耐盐和抗剪切性。     

疏水缔合水溶性聚合物P(AM/NaAA/DiAC16)水溶液的黏度行为

采取前加碱二元胶束共聚-后水解法合成了三元疏水缔合水溶性聚合物聚(丙烯酰胺/丙烯酸钠/N,N-双烯丙基十六胺)[P(AM/NaAA/DiAC16)],研究了其水溶液的黏度行为。当x(DiAC16)=0.10%~0.40%时,在30℃、1 mol/LNaCl水溶液中,P(AM/NaAA/DiAC16)的特性黏数[η]、Huggins常数KH、黏均相对分子质量Mη分别为22.59~19.62 dL/g、0.144~0.294和12.49×106~10.47×106g/mol;KH小于0.8,表明其分子内缔合作用较弱。P(AM/NaAA/DiAC16)在矿化度为19 334μg/g盐水溶液中的表观黏度随疏水单体用量的增加而增加,随温度、剪切速率的增加而降低。在NaCl、CaCl2的离子强度分别为1.26×10-3~4.88×10-3mol/kg、1.07×10-4~5.28×10-4mol/kg的水溶液中,P(AM/NaAA/DiAC16)出现盐增黏现象,疏水单体用量越高,盐增黏效应越显著。当ρ(SDS)=0~0.07 g/dL时,P(AM/NaAA/DiAC16)水溶液的表观黏度有明显增加,表明P(AM/NaAA/DiAC16)/SDS分子缔合作用较强。     

Hydrophobically modified poly(sodium 2‐acrylamido‐2‐methylpropanesulfonate): synthesis and viscosity of aqueous solution

BACKGROUND: Hydrophobically modified polyelectrolytes are widely used polymers due to their good water solubility, stretched configuration in water and strong hydrophobic association. The study reported here aimed at researching the double action of hydrophobic association and electrostatic effect of novel hydrophobically modified polyelectrolytes in solution. RESULTS: A series of novel hydrophobically modified polyelectrolytes were synthesized by micellar copolymerization with various feed ratios of sodium 2‐acrylamido‐2‐methylpropanesulfonate, N‐n‐dodecylamine and sodium dodecylsulfonate. Their structure was characterized using Fourier transform infrared spectroscopy, nuclear magnetic resonance and gel permeation chromatography, and the viscosities of their aqueous and salt solutions were studied. CONCLUSION: The results show that the addition of the hydrophobic comonomer results in a decrease in molecular weight (M_w). The smaller the initial number of hydrophobes in one micelle, the higher is M_w of the resulting copolymer. The viscosity of PAD‐1.73 polyelectrolyte is less sensitive to salt than those of the others. According to the zero shear viscosity and corresponding concentration, the critical cluster‐forming concentration, critical overlap concentration and critical entanglement concentration of these polymer solutions were determined. Moreover, in the dilute regime the viscosity decreases with increasing salinity, while in the semi‐dilute regime the viscosity decreases first and then increases. It is suggested that in dilute and semi‐dilute regimes, hydrophobic intramolecular association and intermolecular association dominate, respectively. Copyright © 2009 Society of Chemical Industry     

疏水缔合水溶性聚合物P(AM/NaAA/DiAC14)水溶液的黏度行为

采取前加碱二元胶束共聚-共水解法合成了三元疏水缔合水溶性聚合物聚(丙烯酰胺/丙烯酸钠/N,N-双烯丙基十四胺)〔P(AM/NaAA/D iAC14)〕,研究了其水溶液的黏度行为。当x(D iAC14)=0.10%~0.40%时,在30℃、c(NaC l)=1 mo.lL-1水溶液中,P(AM/NaAA/D iAC14)的特性黏数[η]、黏均相对分子质量Mη、Huggins常数KH、平均线团密度ρequ分别为18.88~22.22 dL.g-1、9.98×106~12.24×106g.mol-1、0.117~0.299和0.112~0.132 g.dL-1;KH小于0.8,表明其分子内缔合作用较弱。P(AM/NaAA/D iAC14)在矿化度为19 334μg.g-1盐水溶液中的表观黏度随疏水单体摩尔分数的增加而增加,随温度、剪切速率的增加而降低。在NaC、lCaC l2的离子强度分别为1.26×10-3~4.88×10-3mol.kg-1、1.073×10-4~5.28×10-4mol.kg-1的水溶液中,P(AM/NaAA/D iAC14)出现盐增黏现象,疏水单体摩尔分数越大,盐增黏效应越显著。随疏水单体摩尔分数的增加,临界缔合质量浓度(CAC)降低;与后加的十二烷基硫酸钠(SDS)〔ρ(SDS)=0~0.07 g.dL-1〕的疏水缔合作用增强,黏度增加的幅度增大。     

P(AM/NaAA/DiAC_n)与十二烷基硫酸钠的相互作用

以芘为荧光探针,用稳态荧光光谱法、粘度法研究了疏水缔合水溶性聚合物聚(丙烯酰胺/丙烯酸钠/N,N-双烯丙基N-烷基胺)[P(AM/NaAA/D iACn)(n=12,14,16)]与阴离子型表面活性剂十二烷基硫酸钠(SDS)的疏水缔合行为。随SDS浓度的增加,I1/I3比值不断减小,得到SDS的临界胶束浓度(cm c)约为8×10-8mol/L。水溶液的表观粘度随SDS质量浓度的增加急剧上升,超过一定浓度后又急剧下降;粘度增加的幅度随疏水链长度增加。结果表明,P(AM/NaAA/D iACn)与SDS可形成混合胶束,发生较强的疏水缔合作用。     

Morphology and dynamic mechanical properties of high density polyethylene/petroleum resin/polyethylene–octylene elastomer blends

Summary  In this work a study of the synthesis and characterization of several associative water-soluble polymer families, consisting of acrylamide (AM), N-isopropylacrylamide (NIPAM) and N,N-dihexylacrylamide (DHAM) is presented. Three different polymer structures: telechelic (with hydrophobic groups at the chain ends), multisticker (with hydrophobic groups along the polymer chain) and combined (with hydrophobic groups along the chain as well as at the chain ends) were prepared via free radical solution polymerization, using a hydrophobic initiator derived from 4,4’-azobis(4-cyanopentanoic acid) (ACVA) containing linear chains of 12 carbon atoms (C₁₂). The viscoelastic properties of these different families of associative polymers were investigated using steady-flow experiments in aqueous solution. The structures as a function of surfactant (sodium dodecylsulfate, SDS) concentration and temperature were investigated. It was observed that the viscosity remains fairly constant up to a certain temperature (“breaking point”) and then decreases with increasing temperature. The breaking point occurs at 40 °C in the case of the telechelic polymers, at 50 °C for the multisticker polymers and at 60 °C for the combined polymers.     

Characterization and Solution Properties of a Novel Water-soluble Terpolymer For Enhanced Oil Recovery

Summary  To obtain the polymer with good ageing property and the application in medium- and low-permeability oil layers, the water-soluble hydrophobically acrylamide-modified terpolymer (PAAN) with sodium 2-acrylamido-2-methylpropane sulphonate (NaAMPS) and 2-vinylnaphthalene as a hydrophobic monomer (VN) was synthesized by the micellar copolymerization. The differential scanning calorimetry (DSC) and thermogravimetry (TG) results show that large aromatic groups are incorporated into the PAAN polymer in the form of microblock structure and can increase the rigidity of molecular chains, resulting in the good thermal property of the polymer. The measurement results for intrinsic viscosities of PAAN indicate that the molecular weights of polymers are low and the breakage of the polymer chains can not occur at high shear rate. The polymer exhibits salt-thickening, temperature-thickening, thixotropy and good anti-ageing property. The hydrophobic microdomains and associating three-dimensional networks in the aqueous solution of PAAN were observed respectively by flourescent probe and ESEM.     

Hydrophobically modified acrylamide‐based polybetaines. II. Interaction with surfactants in aqueous solution

The interaction of hydrophobically modified (HM) polybetaines with selected small molecule surfactants in aqueous solution was investigated using rheological and surface tension analyses. The polymers included acrylamide‐based, HM polybetaines containing N‐butylphenylacrylamide (BPAM) and specified amounts of sulfobetaine, 3‐(2‐acrylamido‐2‐methylpropanedimethylammonio)‐1‐propanesulfonate (AMPDAPS), or carboxybetaine, 4‐(2‐acrylamido‐2‐methylpropyldimethylammonio)butanoate (AMPDAB); corresponding control (co)polymers lacking BPAM and/or betaine comonomer(s) were also examined for comparative purposes. Low charge density terpolymers exhibited greater viscosity enhancement with the addition of surfactant compared to the high charge density terpolymers. The addition of sodium dodecyl sulfate (SDS) produced the largest increase in solution viscosity, while N‐dodecyl‐N,N,N‐trimethylammonium bromide (DTAB), N‐dodecyl‐N,N‐dimethylammonio‐1‐propanesulfonate (SB3–12), and Triton X‐100 enhanced polymer solution viscosity to a lesser degree. In most cases, the high charge density carboxybetaine terpolymer exhibited diminished solution viscosity upon surfactant addition. The polymers lacking hydrophobic modification showed no detectable viscosity enhancement in the presence of surfactants. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 658–671, 2004     

Synthesis, structure and properties of hydrophobically associating polymers

Hydrophobically modified water-soluble polymers have recently become the subject of extensive research because of their use as aqueous viscosity modifiers in oil recovery and latex paint systems. In this study, poly(acrylamide) samples modified with small amounts of a hydrophobic monomer (ethylphenylacrylamide) have been prepared by free radical copolymerization using an aqueous micellar process in which the use of a surfactant ensures the solubilization of the hydrophobe. The copolymers exhibit improved thickening properties with respect to homopoly(acrylamide) analogs due to intennolecular hydrophobic associations. The aqueous solution-copolymer properties strongly depend on the amount of surfactant used in the synthesis. The differences observed between the samples are directly related to the copolymer microstructure, that is to a more or less block distribution of the hydrophobic units. The interactions in aqueous solution of a surfactant (sodium dodecylsulfate (SDS)) with these copolymers have been examined. A strong increase in viscosity is observed upon the addition of SDS below its critical micelle concentration, owing to the formation of mixed micelles of SDS and hydrophobic monomers. The complex rheological behavior observed is explained in terms of the balance between inter and intrachain liaisons. The effects of hydrolysis on the hydrophobic interactions are also discussed.     

Flourescent probe and ESEM morphologies of a acrylamide‐based terpolymer in aqueous solution

The terpolymer (PASA) of acrylamide with butyl styrene and sodium 2‐acrylamido‐2‐methylpropane sulfonate was synthesized. The composition and molecular structure were characterized by elemental analysis, UV, FTIR, and ¹H NMR. The aggregation behaviors of PASA were studied by means of the fluorescent probe analysis and environmental scanning electron microscope (ESEM). The flourescent probe analysis indicates that the PASA molecules form excellent hydrophobically associating structures in pure water and with the increase in PASA concentration at low concentrations, the nonpolarity of hydrophobic microdomains and the degree of intermolecular hydrophobic association increase in aqueous and brine solution. ESEM measurements show that gigantic aggregates have been formed in the PASA aqueous solution at the polymer concentration of 0.05 g dL^?1, which is the critical association concentration of the polymer, and excellent solution properties of PASA are attributed to integrated network‐structures formed by PASA in aqueous solution, which are collapsed by the addition of salt, resulting in the decrease in apparent viscosity of PASA in brine solution. However, with the increase in the NaCl concentration or the PASA concentration, the number and size of aggregates increase, leading to the remarkable increase in the apparent viscosity of PASA in brine solution. These results are consistent with the AFM and viscosity study results. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103:277–286, 2007     

Synthesis and viscoelastic behavior of water-soluble polymers modified with strong hydrophobic side chains

A new series of associating polymers were prepared by grafting highly hydrophobic side chains: poly(n-butyl acrylate), PNBA; poly(n-butyl methacrylate), PNBMA; and poly(N-(tert-butyl)acrylamide), PTBA of different sizes onto a poly(sodium acrylate), PAANa, backbone. Due to the strong hydrophobic character of the stickers, the dynamics of the associations is very slow as compared to more conventional water-soluble polymers modified with short alkyl chains and the physical associations mainly behave as chemical ones in the experimental conditions. As a consequence, all the copolymers readily self-assemble in aqueous solution forming clusters in very dilute conditions and then gels at higher concentrations. From dynamic measurements, it was shown that the copolymer solutions follow the same scaling relation η^∗ ∼ c^a, where a is a frequency dependent exponent. In these conditions, all the copolymer solutions exhibit a sol-gel transition which obeys the main rules of the percolation theory. For each copolymer, the critical gel concentration c_g depends strongly on the hydrophobic character of the stickers and a single master curve can be drawn by plotting the complex viscosity vs. the reduced concentration, c/c_g. Although the temperature dependence of the viscoelastic properties is very weak, due to the slow dynamics of the associations, it was clearly evidenced that the alkyl acrylamide derivative (PAANa-g-PTBA) exhibits a slight thermothickening behavior which contrasts with the thermothinning behavior of alkyl(meth)acrylate derivatives (PAANa-g-PNBA and PAANa-g-PNBMA). The opposite type of behavior is explained by the presence of the amide function which is known to play an important role in the LCST (lower critical solution temperature) phase diagram of N-alkyl derivatives.     

AM/AMPS/SMA三元共聚物的合成及其性能研究

采用自由基胶束聚合法制备了丙烯酰胺/甲基丙烯酸十八酯/2-甲基-2-丙烯酰胺基丙磺酸三元疏水缔合共聚物(HAPAM),系统研究了HAPAM水溶液的流变行为。结果表明,在聚丙烯酰胺大分子主链上引入阴离子基团和疏水基团后。阴离子的电粘效应与疏水基团的疏水缔合作用相互协同作用,使得共聚物水溶液的粘度明显提高;盐溶液对疏水缔合作用的增强效应与阴离子基团的耐盐性相互结合,使HAPAM水溶液的抗盐性能得以明显提高;HAPAM在水溶液中可以有效的形成大量疏水微区,因而具有较好的耐温耐盐和增粘性能。     

Synthesis and aqueous solution behavior of hydrophobically modified polyelectrolytes

The hydrophobically modified polyelectrolytes were prepared by a micellar technique from acrylamide, n‐alkylacrylamides, and a third monomer, sodium acrylate or sodium 2‐acrylamide‐2‐methylpropanesulfonate. Synthesis and solution properties of the terpolymers were studied. In the synthesis process, the type and amount of surfactant and anionic monomers influenced their solution behavior greatly. The terpolymers showed strong synergistic viscosification effects between their ions and hydrophobic groups. Their aqueous brine solutions exhibit high viscosity at low polymer concentration and can maintain the viscosity during aging at a high temperature (80°C). © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3552–3557, 2001     

脂肪醇嵌段聚醚丙烯酸酯与丙烯酰胺共聚物及其水溶液特性的研究

本文合成了脂肪醇嵌段聚醚丙烯酸酯单体 ,并与丙烯酰胺共聚 ,得到共聚物PEPO PAM。芘荧光光谱分析表明 ,该聚合物在水溶液中依靠分子链上的疏水基团形成一定的缔合作用。PEPO PAM相对于部分水解聚丙烯酰胺 (HPAM )具有更好的增粘性。通过调整分子的组成 ,可使该聚合物不仅具有较强的增粘性 ,同时具有良好的水溶性。     

Self-dissociation of water-soluble PANa/ETC nano-aggregates

Complexation between poly(sodium acrylate) (PANa) and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide methiodide (ETC) in water, which leads to the formation of vesicle-like aggregates, was studied. Different from reported nano-aggregates of polymer complexes that may dissociate when being stimulated, the nano-aggregates of PANa/ETC complexes dissociate automatically in the aqueous solution at ambient environment, exhibiting a behavior similar to that of the nano-aggregates composed of degradable polymers. In the newly formed nano-aggregates, there are hydrophobic domains with a hydrophobicity close to that of hexane. Along with the dissociation, the hydrophobic domains vanish gradually.