Rheological properties and stability of shear thickening fluids based on silica and polypropylene glycol

2019 ◽  
Vol 6 (11) ◽  
pp. 115702 ◽  
Author(s):  
P Nakonieczna ◽  
J Wojnarowicz ◽  
Ł Wierzbicki ◽  
M Leonowicz
2014 ◽  
Vol 87 ◽  
pp. 91-97
Author(s):  
Łukasz Wierzbicki ◽  
Marcin Leonowicz

It was shown that fumed silica particles (FS), dispersed in polypropylene glycol (PPG), form shear thickening fluids (STF). PPGs with different molar mass were tested. The best combination of the properties (high viscosity, obtained at high shear rate) present the fluids composed of 7 nm FS and PPG 425. The highest volume fraction of FS, which was possible to disperse in PPG 425, was 25%. This fluid exhibited the highest viscosity. The highest magnitude of shear thickening effect was obtained, however, for 17.5 vol.% of the solid phase. Dynamic oscillatory shear experiments were conducted at either a constant amplitude or frequency. The constant strain amplitude tests showed, that for the frequency sweep, the systems showed viscous properties, except that of 25 vol.% of FS in PPG 425, which exhibited elastic properties in almost entire range of the frequency investigated. For the constant strain sweep, for low strains, the elastic modulus and loss modulus were hardly dependent on the strain, but for relatively high strain, this dependency was increasing. Also the complex viscosity was also growing for high strain values.


Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3870
Author(s):  
Paulina Nakonieczna-Dąbrowska ◽  
Rafał Wróblewski ◽  
Magdalena Płocińska ◽  
Marcin Leonowicz

Synthesis and characterization of composite shear thickening fluids (STFs) containing carbon nanofillers are presented. Shear thickening fluids have attracted particular scientific and technological interest due to their unique ability to abruptly increase viscosity in the case of a sudden impact. The fluids have been developed as a potential component of products with high energy absorbing efficiency. This study reports on the rheological behavior, stability, and microstructure of the STFs modified with the following carbon nanofillers: multi-walled carbon nanotubes, reduced graphene oxide, graphene oxide, and carbon black. In the current experiment, the basic STF was made as a suspension of silica particles with a diameter of 500 nm in polypropylene glycol and with a molar mass of 2000 g/mol. The STF was modified with carbon nanofillers in the following proportions: 0.05, 0.15, and 0.25 vol.%. The addition of the carbon nanofillers modified the rheological behavior and impact absorption ability; for the STF containing 0.25 vol.% of carbon nanotubes, an increase of force absorption up to 12% was observed.


2016 ◽  
Vol 61 (3) ◽  
pp. 1511-1514 ◽  
Author(s):  
A. Antosik ◽  
M. Głuszek ◽  
R. Żurowski ◽  
M. Szafran

AbstractThe rheological properties of shear thickening fluids based on silica powder of particles size in range 0.10 – 2.80 μm and poly(propylene glycol) of 425, 1000, 2000 g/mol molar mass were investigated. The effect of particle size and the length of the polymeric chain was considered. The objective of this study was to understand basic trends of physicochemical properties of used materials on the onset and the maximum of shear thickening and dilatant effect. Outcome of the research suggested that an increase in the particle size caused a decrease in dilatant effect and shift towards higher shear rate values. Application of carrier fluid of higher molar mass allowed to increase dilatant effect but it resulted in the increase of the initial viscosity of the fluid.


2011 ◽  
Vol 4 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Jie Ding ◽  
Weihua Li ◽  
Shirley Z. Shen

2021 ◽  
pp. 002199832098424
Author(s):  
Mohsen Jeddi ◽  
Mojtaba Yazdani

Whereas most previous studies have focused on improving the penetration resistance of Shear Thickening Fluids (STFs) treated composites, in this study, the dynamic compressive response of single and multi-ply 3 D E-Glass Fiber Reinforced Polymer (GFRP) composites with the STF matrix was investigated by using a drop-weight low-velocity impact test. The experimental results revealed the STF improved the compressive and cushioning performance of the composites such that with increasing its concentration, further improvement was observed. The five-ply composite containing the STF of 30 wt% silica nanoparticles and 1 wt% carbon nanotubes (CNTs) reduced the applied peak force by 56% and 26% compared to a steel plate and five-ply neat samples, respectively. A series of repeated impacts was performed, and it was found that the performance of high-concentration composites is further decreased under this type of loading.


2007 ◽  
Vol 46 (8) ◽  
pp. 1099-1108 ◽  
Author(s):  
Christian Fischer ◽  
Christopher J. G. Plummer ◽  
Véronique Michaud ◽  
Pierre-Etienne Bourban ◽  
Jan-Anders E. Månson

Author(s):  
Nariman Ashrafi ◽  
Habib Karimi Haghighi

The effects of nonlinearities on the stability are explored for shear thickening fluids in the narrow-gap limit of the Taylor-Couette flow. It is assumed that shear-thickening fluids behave exactly as opposite of shear thinning ones. A dynamical system is obtained from the conservation of mass and momentum equations which include nonlinear terms in velocity components due to the shear-dependent viscosity. It is found that the critical Taylor number, corresponding to the loss of stability of Couette flow becomes higher as the shear-thickening effects increases. Similar to the shear thinning case, the Taylor vortex structure emerges in the shear thickening flow, however they quickly disappear thus bringing the flow back to the purely azimuthal flow. Naturally, one expects shear thickening fluids to result in inverse dynamical behavior of shear thinning fluids. This study proves that this is not the case for every point on the bifurcation diagram.


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