Linear viscoelasticity of polymer latices containing PEO with terminal hydrophobes

Pham, Quang Tho; Thibeault, Jane; Lau, Willie; Russel, William B.

doi:10.1002/1521-3900(200002)151:1<557::aid-masy557>3.0.co;2-h

Cited by 4 publications

(3 citation statements)

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“…The viscosity profiles resembled those reported previously for the same class of HEUR polymer, consisting of a low shear plateau, slight shear-thickening and shear-thinning at high shear rates. The shear-thinning was much more abrupt, and the change in viscosity with shear rate was steeper and exhibited a time-dependent property, which was consistent with the findings reported by Pham . The possible reason for the abrupt shear-thinning is probably related to shear-induced phase separation.…”

Section: Resultssupporting

confidence: 89%

“…The shear-thinning was much more abrupt, and the change in viscosity with shear rate was steeper and exhibited a time-dependent property, which was consistent with the findings reported by Pham. 26 The possible reason for the abrupt shear-thinning is probably related to shearinduced phase separation. With increasing temperature, the degree of shear-thickening became less significant.…”

Section: Resultsmentioning

confidence: 99%

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Rheological Properties of a Telechelic Associative Polymer in the Presence of α- and Methylated β-Cyclodextrins

2006

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The viscosity of hydrophobic ethoxylated urethane (HEUR) solution decreased in the presence of alpha-CD or m-beta-CD; however their interactions were quite different. When the alpha-CD/hydrophobe molar ratio exceeded 5.0, the viscosity was close to that of a PEO solution of similar molecular weight. Oscillatory shear indicated that the mechanically active chains in HEUR solution decreased with the addition of alpha-CD. This agreed with the hypothesis that alpha-CD formed an inclusion complex with the hydrophobic moiety of the HEUR polymer, thereby destroying the transient hydrophobic associative network. The viscosity/temperature relationship of the alpha-CD/HEUR system (for HEUR with 70% of the PEO chains capped at both ends) did not obey the Arrhenius relationship for alpha-CD/hydrophobe molar ratio in the range 0.8-5.0. The low shear viscosity increased with increasing temperature at molar ratio of 1.0, and this was attributed to the competitive complexation of the alpha-CD/hydrophobe and the alpha-CD/PEO chain. Increasing temperature favored alpha-CD/PEO complexation. Comparison between the behavior of alpha-CD/HEUR and m-beta-CD/HEUR resulting from the different binding characteristics was discussed.

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Section: Resultssupporting

confidence: 89%

Section: Resultsmentioning

confidence: 99%

Rheological Properties of a Telechelic Associative Polymer in the Presence of α- and Methylated β-Cyclodextrins

2006

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“…The viscosity profiles resemble those reported previously for the same class of HEUR polymer [Liao et al, 2004], consisting of a low shear plateau, slight shear-thickening and shear-thinning at high shear rates. The shear-thinning is much more abrupt and the change in viscosity with shear rate is steeper and exhibit time-dependent property, which is consistent with the findings reported by Pham [Pham et al, 2000] Addition of a-CD to this polymer solution also causes an abrupt reduction in the viscosity, which is similar to that observed for a-CD/HEUR system. The low shear viscosity for the oc-CD/HM-PEG-IPDI solution were extracted from the Newtonian plateaus and plotted in Figure 5.14, which exhibits a similar trend with some minor differences.…”

Section: Interaction Between A-cd and Fully Capped Peo Systemsupporting

confidence: 90%

Interactions between amphiphilic polymers and cyclodextrins

Liao¹

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The solution properties of various types of telechelic hydrophobically modified ethylene oxide urethane polymer (HEUR) in the presence of cyclodextrins were examined. Methylated (3-cyclodextrin (m-pCD) could effectively reduce the steady shear viscosity and the dynamic moduli of HEUR aqueous solutions. It was found that m-PCD interacts with HEUR in three progressive steps. At very low m-(3CD concentrations, m-pCD encapsulates the hydrophobes of looping HEUR chains, which destabilizes the transient network, while maintaining the number of mechanically active chains. However, the m-pCD/HEUR complex solutions become more sensitive to shear stress. At moderate m-pCD concentrations, m-pCD begins to deactivate the bridging chains resulting in a reduction in the number of mechanically active chains and this further weakens the transient network. Finally, when m-pCD is in excess, the network Methylated P-Cyclodextrin could effectively reduce the steady shear viscosity and dynamic moduli of HEUR aqueous solutions. a-Cyclodextrin was found to reduce the steady shear viscosity and dynamic moduli of HEUR aqueous solutions. However, rehological studies revealed some subtle differences between a-CD/HEUR and m-pCD/HEUR system. For the m-pCD/HEUR system, the temperature dependence of low shear viscosity can be described by Arrhenius equation. On the other hand in a-CD/HEUR system, the low shear viscosity ~ temperature relationship does not follow the Arrhenius relationship, where the viscosity increases with increasing temperature within a defined temperature range, Exhibiting a unique viscosity recovery at elevated temperature. The transient hydrophobic network, which is suppressed by the addition of a-CD is partially restored with increasing temperature, which is evident by dynamic mechanical measurements.

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Rheology of transient networks containing hydrophobically modified cellulose, anionic surfactant and colloidal silica: role of selective adsorption

Berglund¹,

Truong²,

Przybycien³

et al. 2004

Rheologica Acta

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Linear viscoelasticity of polymer latices containing PEO with terminal hydrophobes

Cited by 4 publications

References 0 publications

Rheological Properties of a Telechelic Associative Polymer in the Presence of α- and Methylated β-Cyclodextrins

Rheological Properties of a Telechelic Associative Polymer in the Presence of α- and Methylated β-Cyclodextrins

Interactions between amphiphilic polymers and cyclodextrins

Rheology of transient networks containing hydrophobically modified cellulose, anionic surfactant and colloidal silica: role of selective adsorption

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