Effects of divalent cations, seawater, and formation brine on positively charged polyethylenimine/dextran sulfate/chromium(III) polyelectrolyte complexes and partially hydrolyzed polyacrylamide/chromium(III) gelation

2010 ◽  
Vol 115 (2) ◽  
pp. 1008-1014 ◽  
Author(s):  
Stephen Johnson ◽  
Julieta Trejo ◽  
Masoumeh Veisi ◽  
G. Paul Willhite ◽  
Jenn-Tai Liang ◽  
...  
Keyword(s):  
Dextran Sulfate ◽  
Divalent Cations ◽  
Polyelectrolyte Complexes ◽  
Partially Hydrolyzed Polyacrylamide ◽  
Hydrolyzed Polyacrylamide ◽  
Positively Charged

Prediction of Viscosity for Partially Hydrolyzed Polyacrylamide Solutions in the Presence of Calcium and Magnesium Ions

1981 ◽  
Vol 21 (05) ◽  
pp. 623-631 ◽  
Author(s):  
J.S. Ward ◽  
F. David Martin
Keyword(s):  
Ionic Strength ◽  
Oil Recovery ◽  
Divalent Cations ◽  
Polymer Concentration ◽  
Solution Viscosity ◽  
Shear Rates ◽  
Partially Hydrolyzed Polyacrylamide ◽  
Lower Shear ◽  
Total Ionic Strength ◽  
Hydrolyzed Polyacrylamide

Abstract Loss of solution viscosity in water of increasing ionic strength is a major problem encountered in the use of the partially hydrolyzed polyacrylamide polymers for improved oil recovery. It is recognized widely that the viscosity loss is more drastic in the presence of multivalent cations than is observed for sodium ions. There is, however, little information available on the relationships between total ionic strength, concentrations of multivalent cations, and solution viscosities.The purpose of this study is to establish relationships between total ionic strength, concentration of calcium or magnesium ions, polymer concentration, and the resulting viscosity for partially hydrolyzed polyacrylamides with varying degrees of hydrolysis. Solutions at constant ionic strength with varying ratios of calcium or magnesium to sodium ions are compared, and the loss of viscosity as a function of the fraction of divalent cations in the system is determined. For shear rates in the power-law region, the fractional loss in viscosity is a function of the fraction of multivalent cations and, in the range studied, is independent of the total ionic strength. A more complicated relationship is found at lower shear rates where the fractional viscosity loss does vary with total ionic strength.The relationship in the power-law region should prove valuable in predicting viscosities on the basis of the dependence of viscosity on ionic strength and on multivalent cation concentration at a single ionic strength, eliminating the need for many individual measurements of viscosity. More work is needed before useful predictions will be possible at lower shear rates. Introduction Partially hydrolyzed polyacrylamide (HPAM) polymers are currently the most widely used mobility control polymers for secondary and tertiary oil recovery. Small quantities of HPAM can increase the viscosity of water by two or more orders of magnitude in the absence of added electrolytes. This phenomenal increase in viscosity results from the extremely high molecular weight of these polymers and repulsion between the negative charges along the polymer chain, resulting in maximum chain extension. The latter mechanism leads to one of the greater disadvantages of using HPAM in an oil reservoir. In the presence of the electrolyte molecules in typical oilfield brines, negative charges along the polymer chain are screened from each other by association with cations from the solution. The polymer chains no longer are extended fully, and solution viscosity decreases. Mungan observed that divalent cations have a more pronounced effect on viscosity than univalent cations when compared on the basis of equal weights of the chloride salts.Viscosities have been reported for HPAM solutions in sodium chloride brines of varying strength as well as for solutions in brines containing CaCl2 or MgCl2. Some viscosities also have been reported for solutions in brines containing both sodium and calcium ions, but no systematic study of the viscosity trends in brines with more than one type of cation has been reported.The purpose of this study is to investigate HPAM solutions with varying ratios of univalent to divalent cations and to establish trends of the solution viscosities for different values of degree of polymer hydrolysis, polymer concentration, and total ionic strength. Such trends are useful for predicting a wide range of viscosities from a few basic measurements. SPEJ P. 623^

New insights into physicochemical aspects involved in the formation of polyelectrolyte complexes based on chitosan and dextran sulfate

2021 ◽  
pp. 118436
Author(s):  
Suzana Gonçalves Carvalho ◽  
Aline Martins dos Santos ◽  
Amanda Letícia Polli Silvestre ◽  
Andréia Bagliotti Meneguin ◽  
Leonardo Miziara Barboza Ferreira ◽  
...  
Keyword(s):  
Dextran Sulfate ◽  
Polyelectrolyte Complexes

A new injectable biphasic hydrogel based on partially hydrolyzed polyacrylamide and nanohydroxyapatite as scaffold for osteochondral regeneration

RSC Advances ◽  
2015 ◽  
Vol 5 (12) ◽  
pp. 9089-9096 ◽  
Author(s):  
Newsha Koushki ◽  
Ali Asghar Katbab ◽  
Hossein Tavassoli ◽  
Azadeh Jahanbakhsh ◽  
Mohammad Majidi ◽  
...  
Keyword(s):  
Partially Hydrolyzed Polyacrylamide ◽  
Osteochondral Repair ◽  
Nanocrystalline Hydroxyapatite ◽  
Hydrolyzed Polyacrylamide ◽  
Osteochondral Regeneration ◽  
Novel Scaffold ◽  
Chromium Acetate

Fabrication of an injectable biphasic hydrogel based on partially hydrolyzed polyacrylamide (HPAM), nanocrystalline hydroxyapatite (nHAp), and chromium acetate (Cr(iii)) as a novel scaffold for osteochondral repair has been attempted.

High-throughput ion exchange purification of positively charged recombinant protein in the presence of negatively charged dextran sulfate

2014 ◽  
Vol 30 (2) ◽  
pp. 516-520 ◽  
Author(s):  
Lam Raga A. Markely ◽  
Lutfiye Kurt ◽  
Janet Lau ◽  
Sarthak Mane ◽  
Bing Guan ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Recombinant Protein ◽  
High Throughput ◽  
Dextran Sulfate ◽  
Positively Charged
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