The viscosity dependence on concentration, molecular weight and shear rate of xanthan solutions

1985 ◽  
Vol 14 (2) ◽  
pp. 157-164 ◽  
Author(s):  
M. Milas ◽  
M. Rinaudo ◽  
B. Tinland
Keyword(s):  
Molecular Weight ◽  
Shear Rate ◽  
Viscosity Dependence

scholarly journals Certain Rheological Aspects of Functionalized Guar Gum

2013 ◽  
Vol 2013 ◽  
pp. 1-15 ◽  
Author(s):  
Meenu Kapoor ◽  
Dhriti Khandal ◽  
Ruchi Gupta ◽  
Pinklesh Arora ◽  
Geetha Seshadri ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Shear Rate ◽  
Guar Gum ◽  
Loss Modulus ◽  
Industrial Applications ◽  
Green Technology ◽  
Low Molecular Weight ◽  
Radiation Processing ◽  
Industrial Sectors ◽  
Wide Acceptance

Guar gum and its derivatives are highly important industrial hydrocolloids as they find applications in various industrial sectors. Guar is a polymer of high molecular weight and its aqueous solutions exhibit unique rheological properties, which has led to its wide acceptance by the industry. In certain industrial applications low molecular weight guar and its derivatives are needed, and conventionally chemical depolymerisation of guar is carried out for this purpose. Radiation processing is a novel and green technology for carrying out depolymerization and can be an ideal substitute for chemical depolymerisation technique. In order to study the effect of radiation on guar derivatives, three types of derivatives have been taken in the present study: carboxymethyl, hydroxyethyl, and methyl guar. The effect of 1–50 KGy radiation dose on the rheological behavior of these derivatives has been studied, and the results have been described in the present paper. The effect on storage and loss modulus with respect to frequency and effect on viscosity with respect to shear rate have been discussed in detail.

Effects of Molecular Weight of PC on Thermal Properties of PC/ABS Blends Using High-Shear Rate Processing

Polymer Korea ◽  
2018 ◽  
Vol 42 (4) ◽  
pp. 620-626
Author(s):  
Se Mi Kim ◽  
Hee Jung Park ◽  
Eun Ju Lee ◽  
Seung Goo Lee ◽  
Kee Yoon Lee
Keyword(s):  
Molecular Weight ◽  
Thermal Properties ◽  
Shear Rate ◽  
High Shear Rate ◽  
High Shear

Temperature dependence of tracer diffusion coefficients in polystyrene

1986 ◽  
Vol 1 (1) ◽  
pp. 202-204 ◽  
Author(s):  
Peter F. Green ◽  
Edward J. Kramer
Keyword(s):  
Molecular Weight ◽  
Diffusion Coefficient ◽  
Shear Rate ◽  
Temperature Dependence ◽  
Diffusion Coefficients ◽  
Tracer Diffusion ◽  
Tracer Diffusion Coefficient ◽  
Critical Molecular Weight ◽  
Tracer Diffusion Coefficients ◽  
Monomeric Friction Coefficient

The temperature dependence of the tracer diffusion coefficient D* of long deuterated polystyrene (d-PS) chains of molecular weight M>Mc, where Mc is the critical molecular weight for entanglement, diffusing into highly entangled PS matrices, each of molecular weight P = 2×107, is studied using forward recoil spectrometry. It is found that the temperature dependence of D*/T, reflected primarily in the monomeric friction coefficient, is accurately described by a Vogel equation. The constants that are used to fit these results are independent of M and are the same as those used to fit the temperature dependence of the zero shear rate viscosity of polystyrene.

scholarly journals Critical Shear Rate of Polymer-Enhanced Hydraulic Fluids

Lubricants ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 102
Author(s):  
Pawan Panwar ◽  
Paul Michael ◽  
Mark Devlin ◽  
Ashlie Martini
Keyword(s):  
Molecular Weight ◽  
Shear Rate ◽  
Shear Thinning ◽  
Hydraulic Systems ◽  
Newtonian Viscosity ◽  
Critical Shear Rate ◽  
Base Oil ◽  
Hydraulic Fluids ◽  
Theoretical Predictions ◽  
Dynamics Simulations

Many application-relevant fluids exhibit shear thinning, where viscosity decreases with shear rate above some critical shear rate. For hydraulic fluids formulated with polymeric additives, the critical shear rate is a function of the molecular weight and concentration of the polymers. Here we present a model for predicting the critical shear rate and Newtonian viscosity of fluids, with the goal of identifying a fluid that shear thins in a specific range relevant to hydraulic pumps. The model is applied to predict the properties of fluids comprising polyisobutene polymer and polyalphaolefin base oil. The theoretical predictions are validated by comparison to viscosities obtained from experimental measurements and molecular dynamics simulations across many decades of shear rates. Results demonstrate that the molecular weight of the polymer plays a key role in determining the critical shear rate, whereas the concentration of polymer primarily affects the Newtonian viscosity. The simulations are further used to show the molecular origins of shear thinning and critical shear rate. The atomistic simulations and simple model developed in this work can ultimately be used to formulate polymer-enhanced fluids with ideal shear thinning profiles that maximize the efficiency of hydraulic systems.

Shear-rate, concentration, molecular weight, and temperature viscosity dependences of hyaluronate, a wormlike polyelectrolyte

1993 ◽  
Vol 26 (25) ◽  
pp. 6945-6951 ◽  
Author(s):  
Eric Fouissac ◽  
Michel Milas ◽  
Marguerite Rinaudo
Keyword(s):  
Molecular Weight ◽  
Shear Rate

Thixotropy of aqueous solution of fluorocarbon-modified poly(acrylic acid)

e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Hongqi Hu ◽  
Lin Li ◽  
Mingcai Chen
Keyword(s):  
Aqueous Solution ◽  
Shear Rate ◽  
Acrylic Acid ◽  
Rheological Properties ◽  
Great Increase ◽  
Hydrophobic Association ◽  
Chain Elongation ◽  
Shear Rates ◽  
Viscosity Dependence ◽  
Poly Acrylic Acid

AbstractThe rheological properties of the aqueous solution of 1H,1H,11Hperfluoroundecyl acrylate -modified poly(acrylic acid) were studied. It was found that the solutions show different viscosity dependence on shear time at different pH and shear rates. At lower pH and moderate shear rates, the viscosity of the solutions shows a great increase with time. At pH 5.0 and above, it exhibits thixotropy at any shear rate, i.e., the viscosity decreases with time at constant shear rates. If the shearing stops, the viscosity of the solutions can be recovered to some extent. These phenomena are interpreted to be due to the intermolecular hydrophobic association: the construction of the association leads to an increase of the viscosity, the destroying of the association leads to a decrease of the viscosity. The pH-induced conformational change and the shearing-induced chain elongation jointly influence the intermolecular hydrophobic association.

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