Rheological properties of wood polymer composites at high shear rates

2016 ◽  
Vol 51 ◽  
pp. 58-62 ◽  
Author(s):  
Krzysztof Lewandowski ◽  
Kazimierz Piszczek ◽  
Stanisław Zajchowski ◽  
Jacek Mirowski
Keyword(s):  
Rheological Properties ◽  
Polymer Composites ◽  
High Shear ◽  
Shear Rates ◽  
High Shear Rates ◽  
Wood Polymer ◽  
Wood Polymer Composites

Rheology of Nanofluids in Microchannels

2008 ◽  
Author(s):  
Fre´de´ric Ayela ◽  
Olivier Tillement ◽  
Julien Chevalier
Keyword(s):  
Rheological Properties ◽  
Peclet Number ◽  
High Shear ◽  
Shear Rheology ◽  
Péclet Number ◽  
Shear Rates ◽  
High Shear Rates ◽  
On Chip ◽  
Very High ◽  
High Shear Rheology

Microfluidics is often presented for applications where only microliters sample volumes are available. But the benefits of microchannels do not reduce to a low consumption of fluids. From a physical and mechanical point of view, microfluidics can offer high shear rates combined with low Reynolds number and low viscous heating. It becomes possible to explore high shear rheology on a lab-on-chip. We have micromachined microviscometers to study the rheological properties of nanofluids under very high shear rates conditions. Nanofluids are fluid suspensions of solid nanoparticles. Recent experiments have indicated an anomalous increase in thermal conductivity of these suspensions. But less attention has been payed to the rheological properties of nanofluids. The few results concerning the viscosity of nanofluids exhibit scattered values higher than those of fluid suspensions of microparticles, because of a higher rate of collisions due to Brownian motion and shearing motion which enhance aggregation. These experiments were performed with commercially available rheometers over a limited range of shear rates. Our viscometers on chip are silicon — Pyrex microchannels (H ≈ 10 – 20 μm) equipped with local pressure drop sensors. Nanofluids under test were ethanol-based SiO2 nanoparticles. For particle sizes from 20 nm to 190 nm, and solid volume fractions from 1.4% to 7%, a newtonian behaviour has been observed up to 5.104 s−1. High shear rheology is the only way to reach high Peclet number values with nanoparticles in a laminar flow. It was possible to cover a wide range of Peclet number and to have Pe > 1 with diameter in the tens of nanometers range. Our results have demonstrated that an apparent solid volume fraction φa > φ, due to aggregation, was responsible of the increment of viscosity. More important was the demonstration that the shape of the clusters could be modified and that the ratio φa/φ could be lowered by a very high shear rate. Very high shearing rates in microchannels appear to be a way for nanofluids to converge to a well-defined value of viscosities.

scholarly journals Rheological Properties of Superparamagnetic Iron Oxide Nanoparticles

2021 ◽  
Vol 8 (1) ◽  
pp. C29-C37
Author(s):  
T. Javanbakht ◽  
S. Laurent ◽  
D. Stanicki ◽  
I. Salzmann
Keyword(s):  
Shear Stress ◽  
Iron Oxide ◽  
Shear Strain ◽  
Rheological Properties ◽  
Superparamagnetic Iron Oxide ◽  
Oxide Nanoparticles ◽  
High Shear ◽  
Shear Rates ◽  
High Shear Rates ◽  
Positively Charged

The present study focuses on the rheological properties of polyethylene glycol (PEG) modified, positively charged, and negatively charged superparamagnetic iron oxide nanoparticles (SPIONs) at different temperatures. We hypothesized that the surface properties of these nanoparticles in the water did not affect their rheological properties. These nanoparticles had not the same surface properties as SPIONs-PEG had not to charge on their surface whereas positively charged and negatively charged ones with amine and carboxyl groups as their surfaces had positive and negative surface charges, respectively. However, their rheological behaviors were not different from each other. The comparative rheological study of SPIONs revealed their pseudo-Newtonian behavior. The viscosity of SPIONs decreased with the increase in temperature. At low shear rates, the shear stress of SPIONs was independent of rate and increased with the increase of rate. Moreover, at high shear rates, the shear stress for PEG-SPIONs was more than those for positively charged and negatively charged SPIONs. These measurements also revealed that at high shear rates, the shear stress of samples decreased with the increase of temperature. The shear stress of samples decreased with the increase of shear strain and the temperature. We also observed that all the samples had the same amount of shear strain at each shear stress, which indicated the exact resistance of SPIONs to deformation. Furthermore, the shear modulus decreased with time for these nanoparticles. These results suggest that these nanoparticles are promising candidates with appropriate properties for fluid processing applications and drug vectors in biomedical applications.

The Physicomechanical and Rheological Characteristics of Wood–polymer Composites Based on Thermally and Mechanically Modified Filler

2017 ◽  
Vol 44 (2) ◽  
pp. 49-54 ◽  
Author(s):  
S.I. Volfson ◽  
I.Z. Fayzullin ◽  
I.N. Musin ◽  
A.Z. Fayzullin ◽  
A.N. Grachev ◽  
...  
Keyword(s):  
Rheological Properties ◽  
Polymer Composites ◽  
Wood Flour ◽  
Considerable Effect ◽  
Rheological Characteristics ◽  
Wood Polymer ◽  
Mechanochemical Modification ◽  
Wood Polymer Composites

The effect of different wood fillers on the physicomechanical and rheological properties of wood–polymer composites was studied. It was shown that thermal and mechanochemical modification of wood flour has a considerable effect on the properties of wood–polymer composites.

scholarly journals Rheological properties of wood polymer composites and their role in extrusion

2015 ◽  
Vol 602 ◽  
pp. 012014 ◽  
Author(s):  
I Duretek ◽  
S Schuschnigg ◽  
A Gooneie ◽  
G R Langecker ◽  
C Holzer
Keyword(s):  
Rheological Properties ◽  
Polymer Composites ◽  
Wood Polymer ◽  
Wood Polymer Composites

Effect of fiber and polymer variability on the rheological properties of wood polymer composites during processing

2018 ◽  
Vol 40 (S1) ◽  
pp. E609-E616 ◽  
Author(s):  
Mourad Saddem ◽  
Ahmed Koubaa ◽  
Hassine Bouafif ◽  
Sébastien Migneault ◽  
Bernard Riedl
Keyword(s):  
Rheological Properties ◽  
Polymer Composites ◽  
Wood Polymer ◽  
Wood Polymer Composites
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