scholarly journals Analysis and Modeling of Viscosity for Aqueous Polyurethane Dispersion as a Function of Shear Rate, Temperature, and Solid Content

ACS Omega ◽  
2020 ◽  
Vol 5 (40) ◽  
pp. 26237-26244
Author(s):  
Yuegang Liu ◽  
Zhuo Meng ◽  
Yacheng Wang ◽  
Peibo Li ◽  
Yize Sun
Keyword(s):  
Shear Rate ◽  
Solid Content ◽  
Polyurethane Dispersion

Physical Aging and Thixotropy in Sludge Rheology

2008 ◽  
Vol 18 (1) ◽  
pp. 13495-1-13495-8 ◽  
Author(s):  
J.C. Baudez
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Physical Aging ◽  
Abrupt Change ◽  
Rheological Behaviour ◽  
Critical Value ◽  
Solid Content ◽  
Structural Parameter ◽  
Critical Shear Rate ◽  
A New Technique

Abstract Sewage sludge presents a dual rheological behaviour with an abrupt change between the two regimes. Using a new technique of reconstruction of the velocity profile, the behaviour can be modelled by a unique equation including liquid and solid components but also a structural parameter. It is also rigorously demonstrated that the only one rheological behaviour in steady state in the liquid regime is a truncated power-law which can be defined only for a shear rate and a shear stress higher than a critical value, γ̇c and τc. Moreover, the critical shear rate and shear stress increase with the solid content and depend on the fractal dimension of flocs which implies that thixotropic effects are all the more important as the sludge is thick and fresh.

Preparation and Properties of Waterborne Side-Chain Fluorinated Polyurethane

2013 ◽  
Vol 833 ◽  
pp. 374-377
Author(s):  
Ying Qiang Zhang ◽  
Chong Zhe Zhong ◽  
Wei Xu ◽  
Zhen Wu ◽  
Wen Jun Chen ◽  
...  
Keyword(s):  
Particle Size ◽  
Solid Content ◽  
Good Stability ◽  
Side Chain ◽  
Isophorone Diisocyanate ◽  
Polyurethane Dispersion ◽  
Fluorinated Polyurethane ◽  
Emulsion Film ◽  
Polyether Polyol

Waterborne side-chain fluorinated polyurethanes were prepared from fluorine-containing polyether polyol, N210, isophorone diisocyanate (IPDI) as main materials through self-emulsified method. The factors on FWPU, including the particle size and distribution, solid content, the acid and alkali resistant properties of emulsion film, were investigated. The results indicated that the particle size of fluoronated polyurethane dispersion was small, and dispersion had good stability. The emulsion film had better chemical resistant properties.

Rheological behavior of sewage sludge with high solid content

2015 ◽  
Vol 71 (11) ◽  
pp. 1686-1693 ◽  
Author(s):  
Yingchao Cheng ◽  
Huan Li
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Exponential Model ◽  
Organic Content ◽  
Complex Model ◽  
Solid Content ◽  
High Solids ◽  
Pseudoplastic Fluid ◽  
Model Combining ◽  
Solids Content

Sludge rheological properties play a fundamental role in determining its performance in pipes, tanks or reactors. However, the relative information on high-solids sludge is very rare. In this study, the rheological properties of high-solids sludge were investigated systematically and a new rheological model was built. The results showed that the low-solids sludge with total solids content (TS) 2–15% was pseudoplastic fluid, and the high-solids sludge with TS 7–15% exhibited thixotropic property. Sludge viscosity increased exponentially with the increasing TS, and decreased in function of power along with the increasing shear rate. The new complex model combining the exponential model and the power model can perfectly describe the relation between TS, shear rate and viscosity of the high-solids sludge. Both sludge organic content and temperature have influence on sludge viscosity, but the influence was not significant for the low-solids sludge. For the high-solids sludge with TS 6%, 8%, 10% and 12%, their viscosities increased by 5.0, 9.1, 25.7 and 24.9 times, respectively, when sludge organic content increased from 28% to 53%, and decreased by 36.5%, 49.5%, 54.0% and 65.4%, respectively, when sludge temperature rose from 9 to 55 °C.

Thixotropic Strength and Thixotropic Criteria in Semi-Solid Processing

2008 ◽  
Vol 141-143 ◽  
pp. 319-323 ◽  
Author(s):  
W.C. Keung ◽  
Y.F. Lee ◽  
Wei Wei Shan ◽  
Shou Jing Luo
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Shape Factor ◽  
Shear Thickening ◽  
Solid Material ◽  
Solid Content ◽  
Solid Particles ◽  
Thixotropic Behavior ◽  
Semi Solid ◽  
Constant Shear Rate

Thixotropy is essential to semi-solid processing, and because of it the semi-solid material is characterized by ‘shear shinning’. Here, thixotropic strength and thixotropic criteria in semi-solid processing are put forward based on related theories and experiments, and thixotropic mechanism and its influencing factors are also investigated. The results are as follows: 1) the term of thixotropic strength means that with constant shear rate at semi-solid temperature, the semi-solid body begins to flow when the shear stress reach a certain value. This value of shear stress is defined as the thixotropic strength; 2) Thixotropic behavior happens with ‘shear thinning’ because of the deagglomeration of solid particles, while ‘shear thickening’ happens because of the agglomeration at the same time. With increasing shear time, the shear stress increases first and then decreases rapidly to reach a stable value. 3) There are three important factors that influence ‘thixotropic strength’: temperature (hence solid content), initial microstructure (including size, shape factor and uniformity of solid particles) and shear rate.

Characteristics of Styrene-Acrylate Micro Emulsion with High Solid Content and their Effect on the Coating Properties

2013 ◽  
Vol 791-793 ◽  
pp. 44-47 ◽  
Author(s):  
Hong Wei Zhang ◽  
Song Nan Nan ◽  
Yong Hua Lei
Keyword(s):  
Shear Rate ◽  
Water Retention ◽  
Flow Characteristic ◽  
Raw Materials ◽  
Solid Content ◽  
High Solid Content ◽  
Coating Properties ◽  
High Solid ◽  
Transmission Electron ◽  
Micro Emulsion

The cross-linked/non-crosslinked styrene-acrylate micro emulsion with high solid content were synthesized using styrene (St), butyl acrylate (BA), acrylic acid (AA), methyl acrylate (MMA), N-hydroxymethyl acrylamide (NMA) as the raw materials by seeded polymerization, and characterized by Fourier transform infrared spectroscopy (FTIR) and transmission electron microscope (TEM); The coating for the coated paper was prepared by the two kinds of styrene-acrylate micro emulsion, whose effect on the viscosity and water retention of the coating was discussed. The results show that the particles of two kinds of styrene-acrylate micro emulsion are regular sphericity in shape; The apparent viscosity of the coating decreases with the increase of the shear rate, indicating a pseudo-plastic flow characteristic. There is no obvious difference on the viscosity between the two coating under the condition of high shear rate. Compared with the coating prepared by non-crosslinked styrene-acrylate micro emulsion, the coating prepared by cross-linked styrene-acrylate micro emulsion has a bigger viscosity and a better property of water retention.

Adenosine Diphosphate-Induced Aggregation of Human Platelets in Flow Through Tubes: III. Shear and Extrinsic Fibrinogen-Dependent Effects

1994 ◽  
Vol 71 (01) ◽  
pp. 078-090 ◽  
Author(s):  
H L Goldsmith ◽  
M M Frojmovic ◽  
Susan Braovac ◽  
Fiona McIntosh ◽  
T Wong
Keyword(s):  
Shear Rate ◽  
Single Cells ◽  
Adenosine Diphosphate ◽  
Human Platelets ◽  
Size Analysis ◽  
Fibrinogen Concentration ◽  
Human Fibrinogen ◽  
Shear Rates ◽  
Rate Dependent ◽  
Induced Aggregation

SummaryThe effect of shear rate and fibrinogen concentration on adenosine diphosphate-induced aggregation of suspensions of washed human platelets in Poiseuille flow at 23°C was studied using a previously described double infusion technique and resistive particle counter size analysis (1). Using suspensions of multiple-centrifuged and -washed cells in Tyrodes-albumin [3 × 105 μl−1; (17)] with [fibrinogen] from 0 to 1.2μM, the, rate and extent of aggregation with 0.7 μM ADP in Tyrodes-albumin were measured over a range of mean transit times from 0.2 to 43 s, and at mean tube shear rates, Ḡ, = 41.9, 335 and 1,335 s−1. As measured by the decrease in singlet concentration, aggregation at 1.2 μM fibrinogen increased with increasing Ḡ up to 1,335 s1, in contrast to that previously reported in citratcd plasma, in which aggregation reached a maximum at Ḡ = 335 s−1. Without added fibrinogen, there was no aggregation at Ḡ = 41.9 s1; at Ḡ = 335 s1, there was significant aggregation but with an initial lag time, aggregation increasing further at Ḡ = 1,335 s−1. Without added fibrinogen, aggregation was abolished at all Ḡ upon incubation with the hexapeptide GRGDSP, but was almost unaffected by addition of an F(ab’)2 fragment of an antibody to human fibrinogen. Aggregation in the absence of added fibrinogen was also observed at 37°C. The activation of the multiple-washed platelets was tested using flow cytometry with the fluorescently labelled monoclonal antibodies FITC-PAC1 and FITC-9F9. It was shown that 57% of single cells in unactivated PRT expressed maximal GPIIb-IIIa fibrinogen receptors (MoAb PAC1) and 54% expressed pre-bound fibrinogen (MoAb 9F9), with further increases on ADP activation. However, incubation with GRGDSP and the F(ab’)2 fragment did not inhibit the prebound fibrinogen. Moreover, relatively unactivated cells (8% expressing receptor, 14% prebound fibrinogen), prepared from acidified cPRP by single centrifugation with 50 nM of the stable prostacyclin derivative, ZK 36 374, and resuspension in Tyrodes-albumin at 5 × 104 μl−1, aggregated with 2 and 5 μM ADP at Ḡ = 335 and 1,335 s−1 in the absence of added fibrinogen. We therefore postulate that a protein such as von Willebrand factor, secreted during platelet isolation or in flow at sufficiently high shear rates, may yield the observed shear-rate dependent aggregation without fibrinogen.

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