EFFECT OF POLYMER CONCENTRATION ON THE RHEOLOGICAL PROPERTIES OF POLYELECTROLYTE SOLUTIONS

2014 ◽  
Author(s):  
Khaled Benyounes
Keyword(s):  
Rheological Properties ◽  
Polymer Concentration ◽  
Polyelectrolyte Solutions

scholarly journals Bottlebrush polymers in the melt and polyelectrolytes in solution share common structural features

2020 ◽  
Vol 117 (10) ◽  
pp. 5168-5175 ◽  
Author(s):  
Joel M. Sarapas ◽  
Tyler B. Martin ◽  
Alexandros Chremos ◽  
Jack F. Douglas ◽  
Kathryn L. Beers
Keyword(s):  
Neutron Scattering ◽  
Correlation Length ◽  
Salt Concentration ◽  
Polymer Concentration ◽  
Structural Features ◽  
Peak Position ◽  
Correlation Peak ◽  
Grafting Density ◽  
Scattering Measurements ◽  
Polyelectrolyte Solutions

Uncharged bottlebrush polymer melts and highly charged polyelectrolytes in solution exhibit correlation peaks in scattering measurements and simulations. Given the striking superficial similarities of these scattering features, there may be a deeper structural interrelationship in these chemically different classes of materials. Correspondingly, we constructed a library of isotopically labeled bottlebrush molecules and measured the bottlebrush correlation peak position q*=2π/ξ by neutron scattering and in simulations. We find that the correlation length scales with the backbone concentration, ξ∼cBB−0.47, in striking accord with the scaling of ξ with polymer concentration cP in semidilute polyelectrolyte solutions (ξ∼cP−1/2). The bottlebrush correlation peak broadens with decreasing grafting density, similar to increasing salt concentration in polyelectrolyte solutions. ξ also scales with sidechain length to a power in the range of 0.35–0.44, suggesting that the sidechains are relatively collapsed in comparison to the bristlelike configurations often imagined for bottlebrush polymers.

The Viscosity of Extremely Low Concentrated Anionic Polyelectrolyte Solutions

1999 ◽  
Vol 9 (4) ◽  
pp. 158-164 ◽  
Author(s):  
Bernhard Gampert ◽  
Christoph Wilkes ◽  
Thomas Eich
Keyword(s):  
Molar Mass ◽  
Polymer Concentration ◽  
Reduced Viscosity ◽  
Counter Ions ◽  
Equivalent Quantity ◽  
Peculiar Characteristic ◽  
Characteristic Behaviour ◽  
Polyelectrolyte Solutions ◽  
Ionizable Groups ◽  
Anionic Polyacrylamide

Abstract Polyelectrolytes are macromolecules which carry a large quantity of ionizable groups along their chains. By dissolving them in suitable solvents, for example water, these groups dissociate in highly charged macroions and an equivalent quantity of low-molecular counter ions. Through the connection between polymer and electrolyte properties this class of materials obtains its peculiar characteristic behaviour. The experiments undertaken here, were carried out using a commercial, anionic polyacrylamide with different hydrolysis factors in aqueous solutions. The reduced viscosity reaches a maximum which depends on the polymer concentration. The maximum also depends on the molar mass and is a function of the hydrolysis factor of the polymer.

Influence of soap/polymer concentration ratio on the rheological properties of lithium lubricating greases modified with virgin LDPE

2009 ◽  
Vol 15 (5) ◽  
pp. 687-693 ◽  
Author(s):  
J.E. Martín-Alfonso ◽  
G. Moreno ◽  
C. Valencia ◽  
M.C. Sánchez ◽  
J.M. Franco ◽  
...  
Keyword(s):  
Rheological Properties ◽  
Concentration Ratio ◽  
Polymer Concentration

scholarly journals Influence of Various Model Compounds on the Rheological Properties of Zein-Based Gels

Molecules ◽  
2020 ◽  
Vol 25 (14) ◽  
pp. 3174 ◽  
Author(s):  
Agnese Gagliardi ◽  
Silvia Voci ◽  
Donatella Paolino ◽  
Massimo Fresta ◽  
Donato Cosco
Keyword(s):  
Rheological Properties ◽  
Polymer Concentration ◽  
Chemical Properties ◽  
Harsh Environments ◽  
Model Compounds ◽  
Physiological Conditions ◽  
Pharmaceutical Applications ◽  
Pharmaceutical Technology ◽  
Gelling Properties ◽  
Physico Chemical

The controlled release of a compound entrapped in a biocompatible formulation is a sought-after goal in modern pharmaceutical technology. Zein is a hydrophobic protein which has several advantageous properties that make it suitable for use as a biocompatible and degradable material under physiological conditions. It is, therefore, proposed for different biomedical and pharmaceutical applications. In particular, due to its gelling properties, it can be used to form a polymeric network able to preserve biomolecules from harsh environments. The current study was designed to investigate the influence of different probes on the rheological properties of gels made up of zein, in order to characterize the systems as a function of the polymer concentration. Four model compounds characterized by different physico-chemical properties were entrapped in zein gels, and different behaviors (viscoelastic or pronounced solid-like characteristics) of the systems were observed. Zein-based gels showed various release profiles of the encapsulated compounds, suggesting that there are different interaction rates between the probes and the polymeric matrix.

Rheological Properties of PAN and Silk Fibroin in Aqueous NaSCN Solutions

2012 ◽  
Vol 557-559 ◽  
pp. 1095-1098
Author(s):  
Jian Wang
Keyword(s):  
Rheological Properties ◽  
Silk Fibroin ◽  
Apparent Viscosity ◽  
Polymer Concentration ◽  
Solution Properties ◽  
Increasing Temperature

The rheological properties of polyacrylonitrile (PAN) and silk fibroin (SF) in the aqueous NaSCN Solutions were investigated in this study. The results show that the solutions possessed slightly pseudo-plastic solution properties. Their apparent viscosity increased with the increasing total polymer concentration, whereas all of these decreased with the increasing temperature. The viscosity of PAN/SF blend solutions decreased with the increase of the SF component.

Influence of hydrophobe fraction content on the rheological properties of hydrosoluble associative polymers obtained by micellar polymerization

e-Polymers ◽  
2012 ◽  
Vol 12 (1) ◽  
Author(s):  
Enrique J. Jiménez-Regalado ◽  
Elva B. Hernández-Flores
Keyword(s):  
Relaxation Time ◽  
Rheological Properties ◽  
Polymer Concentration ◽  
Water Soluble ◽  
Polymer Chains ◽  
Associative Polymers ◽  
Hydrophobically Modified ◽  
Viscosity Increase ◽  
Increase Rate ◽  
Micellar Polymerization

AbstractThe synthesis, characterization and rheological properties in aqueous solutions of water-soluble associative polymers (AP’s) are reported. Polymer chains consisting of water-soluble polyacrylamides, hydrophobically modified with low amounts of N,N-dihexylacrylamide (1, 2, 3 and 4 mol%) were prepared via free radical micellar polymerization. The properties of these polymers, with respect to the concentration of hydrophobic groups, using steady-flow and oscillatory experiments were compared. An increase of relaxation time (TR) and modulus plateau (G0) was observed in all samples studied. Two different regimes can be clearly distinguished: a first unentangled regime where the viscosity increase rate strongly depends on hydrophobic content and a second entangled regime where the viscosity follows a scaling behavior of the polymer concentration with an exponent close to 4.

Rheological properties of functionalised thermosensitive copolymers for injectable applications in medicine

2012 ◽  
Vol 66 (10) ◽  
Author(s):  
Ivana Chamradová ◽  
Lucy Vojtová ◽  
Lenka Michlovská ◽  
Petr Poláček ◽  
Josef Jančář
Keyword(s):  
Rheological Properties ◽  
Sol Gel ◽  
Polymer Concentration ◽  
Test Tube ◽  
Poly Lactic Acid ◽  
Gel Point ◽  
Sol Gel Transition ◽  
Poly Ethylene ◽  
Lower Temperature ◽  
Gel Transition

AbstractFunctionalised triblock copolymers based on poly((lactic acid)-co-(glycolic acid)) and poly(ethylene glycol) (PLGA-PEG-PLGA) further modified with 3-methylenetetrahydrofuran-2,5-dione (itaconic anhydride; ITA) exhibited sol-gel transition induced by increasing temperature. Rheological properties of a series of ITA/PLGA-PEG-PLGA/ITA copolymer concentrations (6–24 mass %) in deionised Milli-Q water were studied by both the test tube inverting method (TTIM) and rheometer. The gel stiffness increased with the polymer concentration shifting the gel point of the copolymer to the lower temperature. The present study demonstrates that each method describes a sol-gel transition, but the combined method gives comprehensive information about changes in colour, viscosity, elastic and loss moduli. Characterisation of such a gel is necessary for its further use, in order to determine whether the material is appropriate as an injectable biomedical hydrogel.

scholarly journals Rheology of polysulfone-N-methylpyrrolidone solutions used in the technology of lithium-ion batteries

2020 ◽  
Vol 30 (1) ◽  
pp. 102-106
Author(s):  
V. G. Kulichikhin ◽  
A.Ya. Malkin ◽  
I.V. Gumennyi ◽  
V.A. Govorov
Keyword(s):  
Activation Energy ◽  
Rheological Properties ◽  
Polymer Concentration ◽  
Lithium Ion ◽  
Type Equation ◽  
Intermediate Stage ◽  
Temperature Dependences ◽  
High Concentrations ◽  
Newtonian Liquids

AbstractThis paper is devoted to the analysis of the rheological properties of polysulfone solutions in N-methylpyrrolidone, which are an intermediate stage in preparing lithium-ionic batteries. The viscosity of the solutions has been measured in wide ranges of shear rate, temperature, and concentration. The crucial role of water in measuring the rheological properties of solutions has been observed and avoided. The solutions under study are Newtonian liquids, but they demonstrate the elasticity at moderately high concentrations. The concentration dependence of viscosity is very strong, and the threshold was found where the viscosity grows unlimitedly due to the transition of the solution to the gel-like state. Temperature dependences of viscosity are described by the Arrhenius-type equation with the activation energy increasing along with an increase in the polymer concentration in solutions.

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