Phase separation induced by dilution in a system of a hydrophobically modified polymer

Thuresson, Krister; Joabsson, Fredrik

doi:10.1016/s0927-7757(98)00827-9

Cited by 15 publications

(27 citation statements)

References 25 publications

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“…The latter seems a reasonable conclusion since microemulsions containing the C 24 EO x C 24 polymer actually phase separated macroscopically upon dilution to 5 wt.% A dilute aqueous phase was formed in equilibrium with a viscous phase, which most likely contained the predominant amount of the microemulsion and the HM-PEG polymer. This observation is in line with other related investigations [8,21].…”

Section: Resultssupporting

confidence: 94%

“…The fraction of bridges, relative to concentration of bridges in 20 wt.% microemulsion, on dilution of the microemulsion. On the abscissa is given the end-to-end distance [9] of a PEG with the same molecular weight as of the mid-block of the HM-P C 21 EO 280 C 21 divided by the average distance between the microemulsion droplets. When the abscissa value is lower than 1, the HM-P is compressed between adjacent droplets.…”

Section: Discussionmentioning

confidence: 99%

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A rheological investigation of the association between a non-ionic microemulsion and hydrophobically modified PEG. Influence of polymer architecture

Antunes

Thuresson

Lindman

et al. 2003

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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Hydrophobically modified polymers (HM-P) typically behave as thickeners in a wide range of systems. The thickening effect in an aqueous solution of this kind of polymer depends on intermolecular hydrophobic associations and also on chain entanglements if the polymer concentration is significantly above the overlap concentration. In the present investigation a rather short end-capped polymer has been investigated at concentrations that are significantly below the overlap concentration. Despite the rather low polymer concentration, polymer chains were connected into a three-dimensional network by using microemulsion droplets as cross-linking points. The simple structure of the solution simplifies interpretations of results since chain entanglements can be expected to be of low importance and only intermolecular hydrophobic associations have to be considered. In particular the rheological response is in most cases well characterized by one single relaxation time and, then, the solution can be rationalized within the framework of the Maxwell model. We have found that the length of the polymer chain's hydrophobic end-groups, as well as the temperature, have a large influence on dynamics of the system, while the length of the hydrophilic mid-block has a relatively small significance. On the other hand, the connectivity in the system depends critically on the microemulsion concentration. Thus, a maximum was found in viscosity as a function of volume fraction, interpreted as being due to a decrease in crosslink lifetime. #

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Section: Resultssupporting

confidence: 94%

Section: Discussionmentioning

confidence: 99%

A rheological investigation of the association between a non-ionic microemulsion and hydrophobically modified PEG. Influence of polymer architecture

Antunes

Thuresson

Lindman

et al. 2003

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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“…T Cp increases with increasing MS EO and decreases with increasing DS methyl and DS ethyl [6]. As discussed above, the effect on the solution viscosity of the polymers also reveals large variations in the strength of the associations [55]. As can be seen in Figure 13.10, T Cp is shifted dramatically when an EHEC is modified with hydrophobic groups.…”

Section: Cloudingmentioning

confidence: 74%

“…They belong to a family of substances that have a reversed relationship between solubility and temperature [9][10][11][12][51][52][53][54][55][56][57][58][59]. This is not the case for some cellulose ethers.…”

Section: Cloudingmentioning

confidence: 99%

Surface‐Active Polymers from Cellulose

Karlson

2010

Surfactants From Renewable Resources

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“…Phase studies have been reviewed exhaustively by Piculell et al, who pioneered research in this area. 46,49,50,60 In general, there are two types of phase separation: associative separation, where polymer and surfactant are enriched in the same phase; and segregative separation, where polymer and surfactant are separated into different phases. 61 It is believed that associative separation occurs when polymer-surfactant interactions dominate, while segregative separation occurs when polymer-solvent interactions dominate.…”

Section: Interaction With Sds In Transitional and Surfactant Domainsmentioning

confidence: 99%

Properties of hydrophobically modified polyacrylamide with low molecular weight and interaction with surfactant in aqueous solution

Shanks

Bryant

2006

J of Applied Polymer Sci

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Hydrophobically modified polyacrylamide (HMPAM), with a molecular weight of 10 4 g/mol, was studied using a range of rheological methods and dynamic light scattering (DLS). DLS measurements indicate that the association of the modified polymer begins at low concentration. The modified polymer with high substitution forms transient networks below the critical concentration, but the networks are disrupted by the micelles formed by the polymer itself, and the networks do not contribute to viscosity enhancement. The modified polymers exhibited surface activity, and so they may be regarded as nonionic polymeric surfactants rather than thickeners. On the other hand, HM-PAM is shown to interact with the surfactant SDS while PAM is inert to SDS. In the hydrophobic domains, it undergoes a surfactant-induced association process; in the hydrophobe-surfactant transition regions, the surfactant binds to the polymer in a noncooperative way and forms a polymersurfactant complex. Contracted polymer chains begin to extend because of electrostatic repulsion, which can overcome the association at surfactant domains. The conformation of HMPAM polymer chains could be controlled by adding a specific amount of surfactant.

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Phase separation induced by dilution in a system of a hydrophobically modified polymer

Cited by 15 publications

References 25 publications

A rheological investigation of the association between a non-ionic microemulsion and hydrophobically modified PEG. Influence of polymer architecture

A rheological investigation of the association between a non-ionic microemulsion and hydrophobically modified PEG. Influence of polymer architecture

Surface‐Active Polymers from Cellulose

Properties of hydrophobically modified polyacrylamide with low molecular weight and interaction with surfactant in aqueous solution

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