Shear degradation of water‐soluble polymers. I. Degradation of polyacrylamide in a high‐shear couette viscometer

Abdel-Alim, A. H.; Hamielec, A. E.

doi:10.1002/app.1973.070171218

Cited by 75 publications

(22 citation statements)

References 9 publications

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“…Applications in EOR have received a lot of attention both scientifically and practically in recent years. In order to achieve the highest possible efficiency in EOR, it is critical to satisfy typical EOR requirements, such as high polymer solution viscosity, low polymer retention in the oil reservoir, and high mechanical, chemical and thermal stability . To satisfy these requirements, one has to modify copolymer properties, especially solution viscosity, and this is only possible through detailed understanding of the copolymerization kinetics (as copolymerization understanding will control copolymer chain microstructure).…”

Section: Introductionmentioning

confidence: 99%

Shear Viscosity of Poly (Acrylamide/Acrylic Acid) Solutions

Riahinezhad

McManus

Penlidis

2016

Macromolecular Symposia

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SummaryAcrylamide (AAm)/Acrylic acid (AAc) copolymers are being used in a wide spectrum of applications, from which enhanced oil recovery (EOR) is the target application in this research study. The shear viscosity of the copolymer solution is extremely important in determining the performance properties of AAm/AAc copolymers. A series of copolymers with selected properties were prepared to study the effect of polymer concentration, copolymer composition, and salinity on the shear viscosity of the copolymer solutions. The results revealed the considerable effect of solution concentration and salinity on shear viscosity. Moreover, the behavior of the copolymer composition showed a maximum with respect to shear viscosity.

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Section: Introductionmentioning

confidence: 99%

Shear Viscosity of Poly (Acrylamide/Acrylic Acid) Solutions

Riahinezhad

McManus

Penlidis

2016

Macromolecular Symposia

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“…The shear rate was 1,74. lo5 s -' and the residence times were 15 s, 30 s, and 60 s. The concentration of the polymer was adjusted so as to give the same values for the shear stress listed in Tab. 3. The MWDs of the degraded polymer are similar to those in water, although the degradation is more pronounced in the methanol/water mixture.…”

Section: Shear Degradution Of P a Amentioning

confidence: 78%

Effects of mechanical stress on the reactivity of polymers: Shear degradation of polyacrylamide and dextran

1979

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The mechanical degradation of polyacrylamide and dextran and the acid hydrolysis of dextran at different pH values is investigated in concentrated solutions in high shear laminar flow fields. The kinetics of degradation of polyacrylamide show that the reaction is first order, the rate constants of degradation are proportional to the molecular weight, and the polymer molecules are broken preferentially near the center of the chain. It is found that shear stress is the controlling factor of the degradation process, the rate constants increasing in poor solvents and with decreasing temperatures. The limiting molecular weight is a direct function of the shear stress. For dextran a transition range exists in which shear degradation is favored by hydrogen ions at pH values at which no hydrolysis occurs in the absence of a shearing field.

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“…Early studies focused on the influence of shear rate on polymer breakdown and thus tended to give the impression that this was the driving factor [5][6][7]. However, the development of models to describe polymer breakdown [8] and also the observation that the rate of permanent shear thinning generally decreased with increasing temperature [9,10] and increased with increasing viscosity [11] led to the gradual recognition that polymer breakdown might be dependent on the shear stress present in solution.…”

Section: Introductionmentioning

confidence: 99%

“…Such shear rates are difficult to obtain in conventional laminar flow viscometers and led to the early development of ultrasonic [13,14], orifice [5], and engine bench test [15] methods of obtaining measurable permanent shear thinning. Studies were also carried out using capillary [16,17] and concentric cylinder [10,18,19] viscometers, but these were generally employed to test very high molecular weight polymers whose solutions showed permanent viscosity loss at 10 4 or 10 5 s -1 . They broadly confirmed the dependence of the onset of permanent viscosity loss on shear rate and molecular weight indicated by Eq.…”

Section: Introductionmentioning

confidence: 99%

“…In the 1960s the technique of gel permeation chromatography (GPC) was first applied to study the change in molecular weight distribution that accompanies permanent shear thinning. This gave variable results, with some studies and conditions producing a preponderance of fragments with half the molecular weight of the starting value [10,12] but others showing randomly sized fragments or the formation of predominantly low molecular weight species [19].…”

Section: Introductionmentioning

confidence: 99%

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Study of Permanent Shear Thinning of VM Polymer Solutions

et al. 2017

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The ultrashear viscometer (USV) has been adapted and employed to investigate the permanent shear thinning of polystyrene solutions in a series of phthalate ester base fluids. The permanent shear stability index based on viscosities measured at 10 6 s -1 , PSSI(10 6 ), has been found to be a convenient way to express the magnitude of permanent shear thinning. When comparing permanent shear thinning at various shear rates in the USV, it is very important to take account of the different times of shear that are present at different shear rates. The PSSI(10 6 ) value divided by the total time of shear is then a useful way of quantifying and comparing permanent shear thinning rates. Tests using polystyrene in different viscosity base fluids have shown that this rate of permanent shear thinning depends on shear stress and not shear rate and varies linearly with polymer concentration. The rate of permanent shear thinning also varies exponentially with shear stress, suggestive of a stress-promoted polymer breakdown process. By using a small volume of test fluid in the USV and solvent extraction after a test, it has proved possible to obtain molecular weight distributions of polymer after shear using gel permeation chromatography (GPC). This indicates that the polymer breakdown process is different at low and high polymer concentrations, with molecule fragmentation at low polymer concentration but mid-chain scission at high concentration. A key feature of the USV is that, unlike other methods currently used to measure permanent shear thinning behaviour of engine oils, it subjects the test fluid to well-defined, controllable high shear conditions. Coupled with the use of GPC, this makes it possible for the first time to relate quantitatively the permanent shear thinning of engine oils to shear conditions and to polymer degradation response.

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Shear degradation of water‐soluble polymers. I. Degradation of polyacrylamide in a high‐shear couette viscometer

Cited by 75 publications

References 9 publications

Shear Viscosity of Poly (Acrylamide/Acrylic Acid) Solutions

Shear Viscosity of Poly (Acrylamide/Acrylic Acid) Solutions

Effects of mechanical stress on the reactivity of polymers: Shear degradation of polyacrylamide and dextran

Study of Permanent Shear Thinning of VM Polymer Solutions

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