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

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.

Effect of Ultra High Molecular Weight Polyacrylonitrile (UHMW-PAN) on the Rheological Behavior of PAN/DMSO Solution

2012 ◽  
Vol 430-432 ◽  
pp. 687-691 ◽  
Author(s):  
Hui Yu Jiang ◽  
Qian Qian Yin ◽  
Mei Hua Zhou ◽  
Ding Pan
Keyword(s):  
Molecular Weight ◽  
Shear Rate ◽  
High Molecular Weight ◽  
Rheological Behavior ◽  
Polymer Mixture ◽  
Steady Increase ◽  
Dmso Solution ◽  
Dynamic Experiments ◽  
Oscillation Test ◽  
Ultra High Molecular Weight

The effects of ultra high molecular weight Polyacrylonitrile (UHMW-PAN) on the rheological behavior of PAN/DMSO solution have been investigated using a cone-plate rheometer in this work. The rheological behavior was characterized by steady shear and oscillation test It is observed from the measurements that, the rheological behavior of the polymer mixture of UHMW-PAN and AMW-PAN makes a difference to the AMW-PAN solution due to macromolecular entanglements, the viscosities of the solutions decreased with the rising of shear rate, shear viscosity rise with the increase of the molecular weight of the UHMW-PAN. For dynamic experiments, a steady increase of both and with the increase of oscillation frequency and molecular weight of UHMW-PAN was seen for all samples. The and increase with the decrease of the temperature or with the increase of the contents of the UHMW-PAN.

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