A Comparison between Hydrophobically End-Capped Poly(ethylene oxide) with Ether and Urethane Bonds

Alami, E.; Abrahmsén-Alami, Susanna; Vasilescu, Marilena; Almgren, Mats

doi:10.1006/jcis.1997.5043

Cited by 28 publications

(31 citation statements)

References 46 publications

(29 reference statements)

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“…The almost linear dependence of the transition concentration on headgroup size is similar to that found for conventional nonionic (polymeric) surfactants (9,10,13,16,17,33). From the literature and our potentiometric experiments it can be derived that electrostatic interactions between polymer backbones are reduced to a large extent at pH 5 due to protonation and counterion binding (34).…”

Section: Steady-state Fluorescence Spectroscopysupporting

confidence: 62%

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Aggregation Behavior of Mono-endcapped Hydrophobically Modified Poly(sodium acrylate)s in Aqueous Solution

Klijn

Kevelam

Engberts³

2000

Journal of Colloid and Interface Science

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Titration microcalorimetry and steady-state fluorescence spectroscopy have been used to study the aggregation of mono-endcapped hydrophobically modified poly(sodium acrylate)s in aqueous solution. Polymers with molecular weights varying between 800 and 31,700 were synthesized by radical polymerization using an initiator and chain transfer agent. The resulting polymers form hydrophobic microdomains in aqueous solutions. The following conditions were applied: no salt and pH 5 and 9, respectively; 1 M sodium citrate and pH 9. At pH 5 the critical aggregation concentration (CAC, the concentration at which microdomains are formed) increases with increasing molecular weight of the polymers. The concentration range for aggregation is about 0.2-2.4 mM. At pH 9 the carboxylic acid groups are deprotonated and electrostatic repulsions are introduced; therefore the concentration for aggregation rises to about 80 mM. Interestingly, in case of polymers having M(n)<1400 the CAC decreases with increasing molecular weight due to a counterion-concentration gradient toward the hydrophobic microdomain. Near the microdomain the counterion binding is increased, reducing the electrostatic repulsions and allowing for lower aggregation concentrations. In the presence of 1 M sodium citrate this anomalous trend is suppressed to a large extent; since the overall counterion binding is increased and the CAC is lower. The concentration for aggregation is then in the same range as at pH 5 in the absence of salt. Copyright 2000 Academic Press.

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Section: Steady-state Fluorescence Spectroscopysupporting

confidence: 62%

“…For surfactant aggregates this should occur over a rather narrow concentration range. However, this is not the case for polymeric surfactants (16)(17)(18). Here the I 1 /I 3 ratio decreases over a larger concentration range; therefore two arbitrary borders were chosen.…”

Section: Steady-state Fluorescence Spectroscopymentioning

confidence: 99%

Aggregation Behavior of Mono-endcapped Hydrophobically Modified Poly(sodium acrylate)s in Aqueous Solution

Klijn

Kevelam

Engberts³

2000

Journal of Colloid and Interface Science

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“…[1][2][3][4][5] Clays, cellulose derivatives, acrylics, and urethanes are used as thickeners in latex paints. 1 Associative thickeners employed in waterborne coatings include cellulose derivatives, hydrophobically modified alkali soluble emulsions (HASE), and hydrophobically modified ethoxylated urethanes (HEURs).…”

Section: Introductionmentioning

confidence: 99%

Vegetable oil based fatty amide as hydrophobes in associative thickener

Pramanik¹,

Mendon²,

Rawlins³

2013

J of Applied Polymer Sci

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A vegetable oil based high performance associative thickener has been designed and synthesized from a hydroxyl functional soybean oil derivative (hydroxyl value 159 mg KOH/g). An isocyanate-terminated prepolymer was synthesized from polyethylene glycol (PEG) and isophorone diisocyanate (IPDI), and end-capped with the hydroxyl functional soybean oil derivative to prepare a hydrophobically modified ethoxylated polyurethane (HEUR) thickener. The synthesis was monitored by infrared spectroscopy via the isocyanate peak at 2258-2270 cm21 . Thickener efficiency was tested with a commercial styrene-acrylic latex UCAR TM 443, an acrylic latex Acronal V R Optive 130 and an alkyd emulsion Worl eeSol V R E 150W. High thickening efficiency was noted in the low shear region, e.g., 0.5 wt % HEUR loading with UCAR 443 increased viscosity from 0.66 P to 3.06 P at a shear rate of 1333 s 21 . The effect of soybean oil fatty amide based rheology modifier as additive in coating was evaluated in terms of gloss, viscosity, sag resistance, and flow and leveling properties.

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“…There is a delicate balance between the driving force for micellization by hydrophobes/water contacts and the penalty paid through loop formation and chain stretching in these flower-like micelles. [1][2][3][4][5][6][7] These association processes are more complex than those of traditional surfactant micelles. It is the secondary association at higher concentrations where the hydrophobic chains can bridge between neighboring micellar cores and where the hydrophilic backbone chains form loops between micelles.…”

Section: Introductionmentioning

confidence: 99%

“…[16][17][18] At steady shear, beyond a critical shear rate, they exhibit shear thinning behavior. [19][20][21][22][23][24][25] More recently, these polymers and their solutions in water have been examined by various scattering and spectroscopic techniques including dynamic and static light scattering, 3,10,[26][27][28][29][30] small angle neutron scattering, small angle x-ray scattering, 9,29,30 static and dynamic fluorescence, 3,13,14,21,31-33 PGSE-NMR, 1,12,25,34 and viscometry. 35 Since the PGSE NMR technique was first demonstrated by Stejskal and Tanner, 36 it has become a powerful technique for studying self-diffusion in polymer systems.…”

Section: Introductionmentioning

confidence: 99%

Self-diffusion of hydrophobically end-capped polyethylene oxide urethane resin by using pulsed-gradient spin echo NMR spetroscopy

et al. 2003

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Hydrophobically End-capped polyethylene oxide Urethane Resin(HEUR)-associating polymers, HEUR 35(8), HEUR 35 (12), and HEUR 35 (18), comprise a polyethylene oxide (PEO) having a molecular weight of 35,000 that is end capped with two C 8 H 17 , C 12 H 25 , and C 18 H 37 alkyl chains, respectively. These associating polymers were synthesized by condensation reactions with polyethylene oxides and alkyl isocyanates. The self-diffusion coefficients of HEUR-associating polymers were measured in aqueous solution by pulsed-gradient spin-echo (PGSE) nuclear magnetic resonance (NMR) spectroscopy. All polymers underwent a decrease in their mean diffusion coefficients as the concentration was increased. However, the dispersion of the diffusion coefficients, β, about the mean fluctuated with changes in concentration. The large dispersion at low concentrations of HEUR 35(8) and HEUR 35 (12) is related to the interaction between hydrophobic end groups, and the large dispersion at high concentrations of HEUR 35(18) is correlated with transient network formation. These results are valuable for predicting the associating mechanism of the large aggregates before and after their critical micelle concentration.

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A Comparison between Hydrophobically End-Capped Poly(ethylene oxide) with Ether and Urethane Bonds

Cited by 28 publications

References 46 publications

Aggregation Behavior of Mono-endcapped Hydrophobically Modified Poly(sodium acrylate)s in Aqueous Solution

Aggregation Behavior of Mono-endcapped Hydrophobically Modified Poly(sodium acrylate)s in Aqueous Solution

Vegetable oil based fatty amide as hydrophobes in associative thickener

Self-diffusion of hydrophobically end-capped polyethylene oxide urethane resin by using pulsed-gradient spin echo NMR spetroscopy

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