Hydrophobically-modified polyacrylamides prepared by micellar polymerization1Part of this paper was presented at the conference on `Associating Polymer', Fontevraud, France, November 1997.1

Candau, Françoise; Selb, Joseph

doi:10.1016/s0001-8686(98)00077-3

Cited by 273 publications

(221 citation statements)

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“…2 mol % DiHexAM). As it is well known that a slight increase in the hydrophobe level strongly affects the association process, 42 we can conclude that in the case of associative polyelectrolytes, a higher hydrophobe level is required to exhibit a strong viscosity enhancement, in comparison with neutral polymers. In agreement with previous findings on other hydrophobically modified polyelectrolytes, this can be attributed to a decrease in the degree of associations between the hydrophobes, arising from intermolecular electrostatic repulsions, that hinder the overlapping and interpenetration of the chains.…”

Section: Onset Of Hydrophobically Driven Aggregationmentioning

confidence: 69%

“…10,42 The polymerization procedure was similar to that described elsewhere. 49,50 The monomer concentration in the feed was kept at 2 wt %, and the initiator concentration was set to 0.8 mol % with respect to the monomer feed.…”

Section: Polymerization Proceduresmentioning

confidence: 99%

“…In the micellar polymerization process, the hydrophobic monomer is solubilized inside the surfactant micelles, whereas the hydrophilic monomers are localized in the aqueous continuous medium. 42 The segregation of the monomers between the micellar interior and the aqueous solution results in a specific hydrophobe distribution in the polymer. In contrast to homogeneous polymerization, which usually leads to a random polymer, micellar polymerization favors the incorporation of the hydrophobic monomers as blocks rather than as isolated units along the backbone.…”

Section: Polymer Synthesis and Characterizationmentioning

confidence: 99%

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Rheological properties of multisticker associative polyelectrolytes in semidilute aqueous solutions

Kujawa

Audibert‐Hayet

Selb

et al. 2004

J Polym Sci B Polym Phys

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102

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Multisticker associative polyelectrolytes of acrylamide (Ϸ86 mol %) and sodium 2-acrylamido-2-methylpropanesulfonate (Ϸ12 mol %), hydrophobically modified with N,N-dihexylacrylamide groups (Ϸ2 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-tohydrophobe 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 ϭ 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 ϭ 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.

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Section: Onset Of Hydrophobically Driven Aggregationmentioning

confidence: 69%

Section: Polymerization Proceduresmentioning

confidence: 99%

Section: Polymer Synthesis and Characterizationmentioning

confidence: 99%

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Rheological properties of multisticker associative polyelectrolytes in semidilute aqueous solutions

Kujawa

Audibert‐Hayet

Selb

et al. 2004

J Polym Sci B Polym Phys

Self Cite

102

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“…This makes it easier for the polymerization of the cationic monomer. At the same time, the octyl chains in polymer molecules crosslink each other in the manner of hydrophobic association [17]. This behavior enhances its intrinsic viscosity.…”

Section: Effect Of the Monomer Feed Ratio On The Copolymerizationmentioning

confidence: 99%

Effect of hydrophobic group on flocculation properties and dewatering efficiency of cationic acrylamide copolymers

Ren

Chen

Zheng

et al. 2007

Reactive and Functional Polymers

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Three kinds of hydrophobically modified copolymers of acrylamide with 3-acrylamido-2-hydroxypropyltrialkylammonium chloride were prepared, in which alkyls were ethyl, butyl and octyl, respectively. The conformations of the hydrophobically modified copolymers were studied using TEM micrograph. The flocculation performances and the dewatering efficiencies were investigated. The results showed that the hydrophobic group could enhance the flocculation properties. The longer the hydrophobic alkyl chain was, the better the flocculation result was. Compared with poly-diallyldimethyl ammonium chloride (PDADMAC) and poly-acrylamide (PAM), the hydrophobically modified polymers showed better performances in turbidity removal and were quite more efficient in dewatering examination.

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“…For the MAM/AA/DiC x AM terpolymers, the molecular weights ranged from 0.75 -1.12 x 10 6 g/mol. Candau et al 55,61 have determined with N-monoalkyl acrylamide hydrophobic monomers that the polymer molecular weights increase with increasing monomer hydrophobicity due to hydrogen bonding. In our case, since the monomers are disubstituted, no polarity effect on molecular weight is observed.…”

Section: Molecular Weight Determination By Classical Light Scatteringmentioning

confidence: 99%

For Stimul-Responsive Polymers With Enhanced Efficiency in Reservoir Recovery Processes

McCormick

Hester²

2004

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This report contains a series of terpolymers containing acrylic acid, methacrylamide and a twin-tailed hydrophobic monomer that were synthesized using micellar polymerization methods. These polymer systems were characterized using light scattering, viscometry, and fluorescence methods. Viscosity studies indicate that increasing the nonpolar character of the hydrophobic monomer (longer chain length or twin tailed vs. single tailed) results in enhanced viscosity in aqueous solutions. The interactions of these polymers with surfactants were investigated. These surfactants include sodium dodecyl sulfate (SDS), cetyl trimethylammonium bromide (CTAB), Triton X-100. Viscosity measurements of DiC 6 AM and DiC 8 AM mixtures indicate little interaction with SDS, gelation with CTAB, and hemimicelle formation followed by polymer hydrophobe solubilization with Triton X-100. The DiC 10 Am terpolymer shows similar interaction behavior with CTAB and Triton X-100. However, the enhanced hydrophobic nature of the DiC 10 polymer allows complex formation with SDS as confirmed by surface tensiometry. Fluorescence measurements performed on a dansyl labeled DiC 10 Am terpolymer in the presence of increasing amounts of each of the surfactant indicate relative interaction strengths to be CTAB>Triton X-100>SDS.A modified model based on Yamakawa-Fujii and Odjik-Skolnick-Fixman theories was found to describe the contribution of electrostatic forces to the excluded volume of a polyelectrolyte in solution. The model was found to be valid for flexible polymer coils in aqueous salt solutions where intermolecular interactions are minimal. The model suggested that a dimensionless group of parameters termed the dimensionless viscosity should be proportional to the dimensionless ratio of solution screening length to polyion charge spacing. Several sets of experimental data from the literature and from our laboratory have been analyzed according to the model and the results suggest that the two dimensionless groups are indeed related by a universal constant. This model has identified the parameters that are important to fluid mobility, thereby revealing methods to enhance solution performance when using polyions solutions as displacing fluids in oil reservoirs. 5 EXECUTIVE SUMMARYTo date, our synthetic research efforts have been focused on the development of stimuli-responsive water-soluble polymers designed for use in enhanced oil recovery (EOR) applications. These model systems are structurally tailored for potential application as viscosifiers and/or mobility control agents for secondary and tertiary EOR methods. The goal of previous synthetic work has been to design novel polymers that exhibit large dilute solution viscosities in the presence of the adverse conditions normally encountered in oil reservoirs (such as high salt concentrations, the presence of multivalent ions, and elevated temperatures). The polymers are also designed to have "triggerable" properties that can be elicited by external stimuli, such as changes in pH and/or sal...

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Hydrophobically-modified polyacrylamides prepared by micellar polymerization1Part of this paper was presented at the conference on `Associating Polymer', Fontevraud, France, November 1997.1

Cited by 273 publications

References 75 publications

Rheological properties of multisticker associative polyelectrolytes in semidilute aqueous solutions

Rheological properties of multisticker associative polyelectrolytes in semidilute aqueous solutions

Effect of hydrophobic group on flocculation properties and dewatering efficiency of cationic acrylamide copolymers

For Stimul-Responsive Polymers With Enhanced Efficiency in Reservoir Recovery Processes

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