Polymer structures and turbulent shear stability of drag reducing solutions

Kim, O. K.; Little, R. C.; Patterson, R. L.; Ting, Robert Y.

doi:10.1038/250408a0

Cited by 45 publications

(27 citation statements)

References 11 publications

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“…However, unlike AV-DRP, drag reducing efficiency of the PEO solution started to almost immediately diminish due to repeated exposure to high shear forces in the turbulent flow and especially inside the pump while AV-DRP was practically stable during the entire test. Our experiments confirmed the results of previous studies that have concluded that the DRPs with a linear structure are very efficient but degrade much more rapidly than branched ones [40].…”

Section: In Vitro Testing Drag Reducing Ability Of Av-drpsupporting

confidence: 92%

Natural Drag-Reducing Polymers: Discovery, Characterization and Potential Clinical Applications

Marhefka

Kameneva

2016

Fluids

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About seven decades ago, it was discovered that special long-chain soluble polymers added to fluid at nanomolar concentrations significantly reduce resistance to turbulent flow (Toms effect). These so-called drag-reducing polymers (DRPs) do not affect resistance to laminar flow. While the flow parameters associated with the Toms effect do not occur in the cardiovascular system, many later studies demonstrated that intravenous injections of DRPs given to experimental animals produced significant hemodynamic effects, such as increasing tissue perfusion, suggesting potential clinical use of these polymers. Moreover, it was found that the specific viscoelastic properties of these polymers make them capable of modifying traffic of blood cells in microvessels and beneficially redistributing them in the blood capillary system-a phenomenon related to rheological properties of DRPs and not related to their specific chemistry. The domain of drag reducing polymers includes many organic and water-soluble, synthetic and natural long-chain molecules. The study presented here employed chemical and rheological methods, as well as macro and microfluidic tests, to characterize the DRP that we discovered in the Aloe vera plant, which was found to be a more powerful drag reducer and less fragile than many synthetic DRPs. The drag-reducing component of aloe gel was purified and chemically identified, which helped to standardize preparation and made this polymer a strong candidate for clinical use. Examples of successful testing of the aloe-derived DRP in animal models are described.

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Section: In Vitro Testing Drag Reducing Ability Of Av-drpsupporting

confidence: 92%

Natural Drag-Reducing Polymers: Discovery, Characterization and Potential Clinical Applications

Marhefka

Kameneva

2016

Fluids

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“…To overcome this limitation, there were various attempts for selecting more efficient, shear, stable polymers. Kim et al11 observed that branched polyacrylamide (PAAM) is more shear stable than linear PAAM. Similar results by Singh et al12, 13 showed that graft copolymers of PAAM and xanthan gum (XG) are fairly shear stable.…”

Section: Introductionmentioning

confidence: 99%

Characterization of drag reducing guar gum in a rotating disk flow

Kim

Lim

Choi

et al. 2002

J of Applied Polymer Sci

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ABSTRACT:The turbulent drag reduction characteristics in a rotating disk apparatus were investigated by using polysaccharide guar gum in deionized water. The ultrasonic degradation method was adopted to obtain different molecular weight fractions of guar gum for this study. The stability of guar gum over time was observed to be better than the typical synthetic water-soluble drag reducers [e.g., poly(ethylene oxide)]. A linear correlation between polymer concentration and the concentration/(drag reduction) for different molecular weights of guar gum was obtained, and the universal drag reduction curve for the guar gum/deionized water system was constructed.

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“…According to Burkholder (Dow Chemical), commercial polyacrylamide (Separan AP-273) contains approximately 30% COO groups. In addition, as pointed out by Kim et al (1974), the conversion of the amide groups (CONH 2) in the polyacrylamide into carboxyl groups (COOH) could occur by intentional hydrolysis as well as by handling and long-term storage in the laboratory, forming copolymers of polyacrylamide and polyacrylic acid. Therefore, it is believed that the addition of a base would increase the ionization of the carboxyl groups, thus increasing the viscosity.…”

Section: Results and Discussion-polyacrylamide Solutionsmentioning

confidence: 98%

Solvent Effects on the Rheology of Aqueous Polyacrylamide Solutions†

Cho

Hartnett

Park

1983

Chemical Engineering Communications

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The influence of solvent chemistry on steady shear viscosityand first normalstressdifference for aqueous polyacrylamide solutions (Separan AP-273) was investigated in the Weissenberg rheogoniometer and capillary tube viscometer. It was round that these rheological properties are particularly sensitive to the chemistry or the solvent. For example, the zero shear rate viscosity or a 1000 wppm Separan solution with distilled water as the solvent was greater than that with Chicago tap water as the solvent by a factor or 25, while the first normal force difference varied by a factor of two. The addition of an acid or a base to the Chicago tap water-Separan solution also influenced the zero shear rate viscosity and first normal force difference. It was round that there is an optimum pH or approximately 10 which yields a maximum value or the zero shear rate viscosity for the Separan-tap water solution.Limited data on the influence of solvent chemistry were obtained for 5()(x)wpprn aqueous solutions of polyethylene oxide (WSR-301) and reveal the same quantitative trends round for the polyacrylamide solutions although the magnitude or the observed changes are smaller.

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Polymer structures and turbulent shear stability of drag reducing solutions

Cited by 45 publications

References 11 publications

Natural Drag-Reducing Polymers: Discovery, Characterization and Potential Clinical Applications

Natural Drag-Reducing Polymers: Discovery, Characterization and Potential Clinical Applications

Characterization of drag reducing guar gum in a rotating disk flow

Solvent Effects on the Rheology of Aqueous Polyacrylamide Solutions†

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