Free‐radical polymerization in micellar media: Effect of microenvironment

Candau, Françoise; Volpert, Edgar; Lacı́k, Igor; Selb, Joseph

doi:10.1002/masy.19961110110

Cited by 18 publications

(19 citation statements)

References 21 publications

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“…60 The choice of a disubstituted AM derivative as the hydrophobic monomer (DiHexAM) is justified by the fact that it minimizes or even suppresses the compositional drift that is observed when monosubstituted AM derivatives are used. 50,61 After describing the synthesis and characterization of the polymers, we focus on their rheological properties in semidilute, salt-free aqueous solutions. The study mainly deals with polymer solutions in the unentangled semidilute regime; the impact of the polymer microstructure on the rheological behavior is described in detail, along with a comparison of the dynamic properties with available theories.…”

Section: Introductionmentioning

confidence: 99%

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: Introductionmentioning

confidence: 99%

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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“…HMWPs are usually prepared from acrylamide and a hydrophobic monomer by means of free‐radical polymerization. Acrylamide is the most useful monomer for obtaining water‐soluble high molecular weight polymers so that its copolymers are among the most extensively investigated 8–13. In spite of the fact that different polymers are used to prepare associated polymers, acrylamide is the most suitable one because its copolymers show the desired effect at polymer concentrations below 1% by weight.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of hydrophobically associated polyacrylamide‐containing aqueous fluids and their potential use in petroleum recovery

Chagas

Machado

Haag

et al. 2004

J of Applied Polymer Sci

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Acrylamide and tridecyl acrylate copolymers were synthesized by micellar copolymerization to obtain water-soluble, hydrophobically modified polymers. Rheological properties of the obtained polymer solutions were evaluated and compared to those of solutions of a commercial polyacrylamide currently used in the petroleum industry. The behavior of the copolymer solutions was studied as a function of the variation of hydrophobic monomer content incorporated in the copolymer as well as the salt content of the aqueous medium, for diluted and semi-diluted regimens. Comparative studies of such effects on the intrinsic viscosity and the critical concentration of those polymers were conducted. The increase in hydrophobic monomer content produced a sudden increase in the bulk and absolute viscosity of the polymeric solutions, a trend that was more intense from a certain concentration typical for each polymer. Salt addition led to lower bulk viscosity caused by a stronger interaction among hydrophobic groups, resulting from minimized exposure of such groups and water. The same effect was observed for the critical concentration. A comparison of the synthesized polymers with industrial polyacrylamide showed that the synthesized polymers were characterized by advantageously high shear strength and high salt resistance. However, in the absence of salts, higher copolymer amounts were needed to prepare solutions whose viscosity was the same as that of commercial polyacrylamide.

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“…Such associations result in an increase of the hydrodynamic size, which increases solution viscosity. Because the high viscosity conveyed by these polymers is attributed to molecular association, on shearing the fluids just disrupt these associations, which are reset when shear is interrupted and initial viscosity is recovered [6][7][8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Solution properties of hydrophobically modified polyacrylamides and their potential use for polymer flooding application

Al-Sabagh

Kandile

El-Ghazawy

et al. 2016

Egyptian Journal of Petroleum

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We tested nine hydrophobically modified polyacrylamides with molecular weights situated between 1.58 and 0.89 Â 10 6 g/mol for enhanced oil recovery applications. Their solution properties were investigated in the distilled water, brine solution, formation water and sea water. Their critical association concentrations were determined from the relationship between their concentrations and the corresponding apparent viscosities (g app ) at 30°C at shear rate 6 s À1 . They were between 0.4 and 0.5 g/dl. The brine solutions of 0.5 g/dl of HM-PAMs were investigated at different conditions regarding their apparent viscosities. Such conditions were mono and divalent cations, temperature ranging from 30 to 90°C, the shear rate ranging from 6 to 30 s À1 and the aging time for 45 days. The surface and interfacial tensions for the HM-PAMs were measured for concentration range from 0.01 to 1 g/dl brine solutions at 30°C and their emulsification efficiencies were investigated for 7 days. The discrepancy in the properties and efficiencies of the tested copolymers was discussed in the light of their chemical structure. Ó 2015 The Authors. Production and hosting by Elsevier B.V. on behalf of Egyptian Petroleum Research Institute. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).

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Free‐radical polymerization in micellar media: Effect of microenvironment

Cited by 18 publications

References 21 publications

Rheological properties of multisticker associative polyelectrolytes in semidilute aqueous solutions

Rheological properties of multisticker associative polyelectrolytes in semidilute aqueous solutions

Evaluation of hydrophobically associated polyacrylamide‐containing aqueous fluids and their potential use in petroleum recovery

Solution properties of hydrophobically modified polyacrylamides and their potential use for polymer flooding application

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