Relationship between polymer concentration and molecular weight in the viscosity behavior of concentrated solution

1968 ◽  
Vol 225 (2) ◽  
pp. 106-111 ◽  
Author(s):  
Takuro Hayahara ◽  
Seiji Takao
Keyword(s):  
Molecular Weight ◽  
Polymer Concentration ◽  
Viscosity Behavior ◽  
Concentrated Solution

The High Pressure Rheology of Mixtures

2004 ◽  
Vol 126 (4) ◽  
pp. 697-702 ◽  
Author(s):  
Scott Bair
Keyword(s):  
Molecular Weight ◽  
High Pressure ◽  
Binary Systems ◽  
Viscosity Coefficient ◽  
Shear Thinning ◽  
Newtonian Viscosity ◽  
Double Shear ◽  
Ideal Mixing ◽  
Viscosity Behavior ◽  
Single Flow

The Newtonian mixing rules for several binary systems have been experimentally investigated. Some systems show non-ideal mixing response and for some systems the non-ideal response is pressure-dependent, yielding an opportunity for manipulation of the pressure-viscosity behavior to advantage. The mixing of differing molecular weight “straight cuts” can produce very different pressure-viscosity response. This behavior underscores the difficulty in predicting the pressure-viscosity coefficient based upon chemical structure and ambient viscosity since the molecular weight distribution is also important, but it also provides another opportunity to control the high-pressure response by blending. The first experimental observation of double shear-thinning within a single flow curve is reported. Blending then provides the capability of adjusting not only the Newtonian viscosity but also the non-Newtonian shear-thinning response as well.

Effect of viscoelasticity on the soft-wall transition and turbulence in a microchannel

2017 ◽  
Vol 812 ◽  
pp. 1076-1118 ◽  
Author(s):  
S. S. Srinivas ◽  
V. Kumaran
Keyword(s):  
Molecular Weight ◽  
Reynolds Number ◽  
Reynolds Stress ◽  
Mass Fraction ◽  
Rectangular Cross Section ◽  
Pure Water ◽  
Polymer Concentration ◽  
Wall Turbulence ◽  
Solution Viscosity ◽  
Soft Wall

The modification of soft-wall turbulence in a microchannel due to small amounts of polymer dissolved in water is experimentally studied. The microchannels are of rectangular cross-section with height ${\sim}$160 $\unicode[STIX]{x03BC}\text{m}$, width ${\sim}$1.5 mm and length ${\sim}$3 cm, with three walls made of hard polydimethylsiloxane (PDMS) gel, and one wall made of soft PDMS gel with an elasticity modulus of ${\sim}$18 kPa. Solutions of polyacrylamide of molecular weight $5\times 10^{6}$ and mass fraction up to 50 ppm, and of molecular weight $4\times 10^{4}$ and mass fraction up to 1500 ppm, are used in the experiments. In all cases, the solutions are in the dilute limit below the critical overlap concentration, and the solution viscosity does not exceed that of water by more than 10 %. Two distinct types of flow modifications are observed below and above a threshold mass fraction for the polymer, $w_{t}$, which is ${\sim}$1 ppm and 500 ppm for the solutions of polyacrylamide with molecular weights $5\times 10^{6}$ and $4\times 10^{4}$, respectively. At or below $w_{t}$, there is no change in the transition Reynolds number, but there is significant turbulence attenuation, by up to a factor of 2 in the root-mean-square velocities and a factor of 4 in the Reynolds stress. When the polymer concentration increases beyond $w_{t}$, there is a decrease in the transition Reynolds number and in the intensity of the turbulent fluctuations. The lowest transition Reynolds number is ${\sim}$35 for the solution of polyacrylamide with molecular weight $5\times 10^{6}$ and mass fraction 50 ppm (in contrast to 260–290 for pure water). The fluctuating velocities in the streamwise and cross-stream directions are lower by a factor of 5, and the Reynolds stress is lower by a factor of 10, in comparison to pure water.

Bifunctional Photobinding of Psoralen to Single Stranded Nucleic Acids

1973 ◽  
Vol 28 (7-8) ◽  
pp. 370-375 ◽  
Author(s):  
S Marciani ◽  
M. Terbojevich ◽  
F Dall 'Acqua ◽  
G. Rodighiero
Keyword(s):  
Molecular Weight ◽  
Light Scattering ◽  
Nucleic Acids ◽  
Dilute Solutions ◽  
Base Pairs ◽  
Bacterial Dna ◽  
Disordered Structure ◽  
Concentrated Solution ◽  
Reduced Rate ◽  
Molecular Weight Of Dna

Abstract As psoralen and other furocoumarin derivatives, intercalated between two base pairs of native DNA, under irradiation at 365 nm form inter-strand cross-linkings as a consequence of bifunctional addition, the writers have investigated the ability of psoralen to give such bifunctional photo­ additions, too, with nucleic acids with disordered or partilly disordered structure (denatured DNA and r-RNA). On the basis of fluorimetric, light-scattering, viscosimetric measurements and of the renaturation ability of denatured bacterial DNA, certain results have been obtained. In addition to monofunctional photoadditions, psoralen can give bifunctional binding by irradiation at 365 nm both with denatured DNA and with r-RNA. However, when irradiation of denatured DNA in the presence of psoralen was performed in a concentrated solution (0.4%), the formation of bifunctional additions between two different strands was demonstrated by the increase (50%) of molecular weight of denatured DNA. However, when irradiation of denatured DNA was performed in more dilute solutions (0.1%), the bifunctional photoaddition of psoralen took place producing only bi­ functional additions in the same strand, very probably with the formation of loops, as has been shown by the absence of increase of molecular weight of DNA and by the more restricted structure assumed by the macromolecule, revealed by the light-scattering and viscosimetric measurements. The formation of these bifunctional additions was confirmed by the reduced rate of renaturation shown by denatured bacterial DNA after irradiation in the presence of psoralen. In the case of r-RNA, psoralen, when irradiated can form bifunctional additions only in the same strand.

Adsorption of monodisperse polybutadienes on carbon black, 3 Displacement of pre-adsorbed molecules by the same polymer. Conformational and molecular weight effects

e-Polymers ◽  
2005 ◽  
Vol 5 (1) ◽  
Author(s):  
Kathy Vuillaume ◽  
Bassel Haidar ◽  
Alain Vidal
Keyword(s):  
Molecular Weight ◽  
Driving Force ◽  
Polymer Concentration ◽  
Gel Permeation Chromatography ◽  
Polymer Chains ◽  
Gel Permeation ◽  
Conformational Factor ◽  
Before And After ◽  
Displacement Processes

AbstractDisplacement of pre-adsorbed macromolecules by the same polymer, polybutadiene, of the same or of different molecular weight was studied in solution and in the bulk. The effect of polymer concentration on pre-adsorption and displacement processes was determined. Displacement was investigated by gel permeation chromatography and by determination of the amount of bound polymer before and after displacement. A conformational factor was established as a major driving force - besides molecular weight - in the displacement process. Polymer chains adsorbed in flat conformation had the highest adsorption stability and could not be displaced by any other molecular weight of the same polymer.

scholarly journals Evaporation-induced Rayleigh–Taylor instabilities in polymer solutions

2020 ◽  
Vol 378 (2174) ◽  
pp. 20190533 ◽  
Author(s):  
E. J. Mossige ◽  
V. Chandran Suja ◽  
M. Islamov ◽  
S. F. Wheeler ◽  
Gerald. G. Fuller
Keyword(s):  
Molecular Weight ◽  
Time Scales ◽  
Polymer Solutions ◽  
Critical Concentration ◽  
Polymer Concentration ◽  
Onset Time ◽  
Dense Layer ◽  
Strong Concentration ◽  
Aqueous Polymer ◽  
Gravitational Instabilities

Understanding the mechanics of detrimental convective instabilities in drying polymer solutions is crucial in many applications such as the production of film coatings. It is well known that solvent evaporation in polymer solutions can lead to Rayleigh-Bénard or Marangoni-type instabilities. Here, we reveal another mechanism, namely that evaporation can cause the interface to display Rayleigh–Taylor instabilities due to the build-up of a dense layer at the air–liquid interface. We study experimentally the onset time ( t p ) of the instability as a function of the macroscopic properties of aqueous polymer solutions, which we tune by varying the polymer concentration ( c 0 ), molecular weight and polymer type. In dilute solutions, t p shows two limiting behaviours depending on the polymer diffusivity. For high diffusivity polymers (low molecular weight), the pluming time scales as c 0 − 2 / 3 . This result agrees with previous studies on gravitational instabilities in miscible systems where diffusion stabilizes the system. On the other hand, in low diffusivity polymers the pluming time scales as c 0 − 1 . The stabilizing effect of an effective interfacial tension, similar to those in immiscible systems, explains this strong concentration dependence. Above a critical concentration, c ^ , viscosity delays the growth of the instability, allowing time for diffusion to act as the dominant stabilizing mechanism. This results in t p scaling as ( ν / c 0 ) 2/3 . This article is part of the theme issue ‘Stokes at 200 (Part 1)’.

Synthesis of Ionic Hydrophobic Associating Polymer and it’s Aqueous Solution‘s Viscosity Characteristics

2014 ◽  
Vol 628 ◽  
pp. 120-124
Author(s):  
Fa Yong Feng ◽  
Pei Zhi Yu
Keyword(s):  
Polymer Concentration ◽  
Synthesis Method ◽  
Water Soluble ◽  
Soluble Polymer ◽  
Water Soluble Polymer ◽  
Viscosity Behavior ◽  
Hydrophobically Associating ◽  
Temperature Shear ◽  
Hydrolyzed Polyacrylamide ◽  
Associating Polymer

Brief introduction of research progresses of hydrophobically associating water soluble polymer, as well as a synthesis method of a hydrophobically associating water-soluble polymer P (AM/KAA/MAHB). Meanwhile the molecular structure is characterized, and the viscosity behavior of the ionic hydrophobic-associating polymer solution is analyzed. The influences of polymer concentration, temperature, shear rate and water salinity of the saline solution on apparent viscosity are discussed. The critical associating concentration of polymer in salt solutions and salt thickening effect are also studied. The results show that the polymer possesses obvious temperature resistance and salt tolerance compared with partially hydrolyzed polyacrylamide polymer.

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