Nonlinear Rheology of Telechelic Associative Polymer Networks: Shear Thickening and Thinning Behavior of Hydrophobically Modified Ethoxylated Urethane (HEUR) in Aqueous Solution

2012 ◽  
Vol 45 (2) ◽  
pp. 888-898 ◽  
Author(s):  
Shinya Suzuki ◽  
Takashi Uneyama ◽  
Tadashi Inoue ◽  
Hiroshi Watanabe
Keyword(s):  
Aqueous Solution ◽  
Polymer Networks ◽  
Shear Thickening ◽  
Nonlinear Rheology ◽  
Hydrophobically Modified ◽  
Associative Polymer

scholarly journals The Chain Distribution Tensor: Linking Nonlinear Rheology and Chain Anisotropy in Transient Polymers

Polymers ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 848 ◽  
Author(s):  
Shankar Lalitha Sridhar ◽  
Franck Vernerey
Keyword(s):  
Shear Rate ◽  
Polymer Networks ◽  
Shear Thickening ◽  
Shear Thinning ◽  
Underlying Mechanism ◽  
Weissenberg Number ◽  
Critical Shear Rate ◽  
Nonlinear Rheology ◽  
Non Gaussian ◽  
Chain Force

Transient polymer networks are ubiquitous in natural and engineered materials and contain cross-links that can reversibly break and re-form. The dynamic nature of these bonds allows for interesting mechanical behavior, some of which include nonlinear rheological phenomena such as shear thickening and shear thinning. Specifically, physically cross-linked networks with reversible bonds are typically observed to have viscosities that depend nonlinearly on shear rate and can be characterized by three flow regimes. In slow shear, they behave like Newtonian fluids with a constant viscosity. With further increase in shear rate, the viscosity increases nonlinearly to subsequently reach a maximum value at the critical shear rate. At this point, network fracture occurs followed by a reduction in viscosity (shear-thinning) with a further increase in shear rate. The underlying mechanism of shear thickening in this process is still unclear with debates between a conversion of intra-chain to inter-chain cross-linking and nonlinear chain stretch under high tension. In this paper, we provide a new framework to describe the nonlinear rheology of transient polymer networks with the so-called chain distribution tensor using recent advances from the transient network theory. This tensor contains quantitatively and statistical information of the chain alignment and possible anisotropy that affect network behavior and mechanics. We investigate shear thickening as a primary result of non-Gaussian chain behavior and derive a relationship for the nonlinear viscosity in terms of the non-dimensional Weissenberg number. We further address the criterion for network fracture at the critical shear rate by introducing a critical chain force when bond dissociation is suddenly accelerated. Finally, we discuss the role of cross-linker density on viscosity using a “sticky” reptation mechanism in the context of previous studies on metallo-supramolecular networks with reversible cross-linkers.

Solution rheology of a hydrophobically modified alkali-soluble associative polymer

1997 ◽  
Vol 41 (2) ◽  
pp. 427-444 ◽  
Author(s):  
Robert J. English ◽  
Harpreet S. Gulati ◽  
Richard D. Jenkins ◽  
Saad A. Khan
Keyword(s):  
Hydrophobically Modified ◽  
Solution Rheology ◽  
Associative Polymer

Hydrophobic Interactions of Poly(N-isopropylacrylamide) with Hydrophobically Modified Poly(sodium acrylate) in Aqueous Solution

1997 ◽  
Vol 30 (26) ◽  
pp. 8293-8297 ◽  
Author(s):  
G. Bokias ◽  
D. Hourdet ◽  
I. Iliopoulos ◽  
G. Staikos ◽  
R. Audebert
Keyword(s):  
Aqueous Solution ◽  
Hydrophobic Interactions ◽  
Sodium Acrylate ◽  
Hydrophobically Modified
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