scholarly journals Impact of the Carbon Nanofillers Addition on Rheology and Absorption Ability of Composite Shear Thickening Fluids

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3870
Author(s):  
Paulina Nakonieczna-Dąbrowska ◽  
Rafał Wróblewski ◽  
Magdalena Płocińska ◽  
Marcin Leonowicz
Keyword(s):  
Carbon Nanotubes ◽  
Graphene Oxide ◽  
Rheological Behavior ◽  
Shear Thickening ◽  
High Energy ◽  
Polypropylene Glycol ◽  
Shear Thickening Fluids ◽  
Carbon Nanofillers ◽  
Energy Absorbing ◽  
Composite Shear

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.

Composition – Property Relations in Shear Thickening Fluids

2014 ◽  
Vol 87 ◽  
pp. 91-97
Author(s):  
Łukasz Wierzbicki ◽  
Marcin Leonowicz
Keyword(s):  
High Strain ◽  
Volume Fraction ◽  
Solid Phase ◽  
Loss Modulus ◽  
Shear Thickening ◽  
Complex Viscosity ◽  
High Viscosity ◽  
Polypropylene Glycol ◽  
Shear Thickening Fluids ◽  
Composition Property

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.

scholarly journals Heat Transfer and Rheological Behavior of Fumed Silica Nanofluids

Processes ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 1535 ◽  
Author(s):  
A.I. Gómez-Merino ◽  
J.J. Jiménez-Galea ◽  
F.J. Rubio-Hernández ◽  
J.L. Arjona-Escudero ◽  
I.M. Santos-Ráez
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Rheological Behavior ◽  
Fumed Silica ◽  
Shear Thickening ◽  
Good Control ◽  
Thermomechanical Properties ◽  
Polypropylene Glycol ◽  
Conductivity Measurements ◽  
Liquid Phases

The addition of nanoparticles to liquid media can improve thermomechanical properties of dispersants. This ability gives rise to the development of multiple applications of nanofluids (NF) in branches so different as electronic and photonic devices or cosmetic industry. Logically, these applications require a good control of heat transfer and flow properties. Moreover, if we consider the necessity to optimize industrial processes in which NF take part, it is necessary to obtain possible relationships between both physical mechanisms. Specifically, in this work, a study about thermal conductivity and rheological behavior of fumed silica suspensions in polypropylene glycol (PPG400) and polyethylene glycol (PEG200) was performed. The study of these two suspensions is interesting because the flow behaviors are very dissimilar (while the fumed silica in PEG200 suspension is viscoplastic, the fumed silica in PPG400 suspension shows shear-thickening behavior between two shear-thinning regions), despite the addition of fumed silica producing similar enhancement of the relative thermal conductivity in both liquid phases. The more outstanding contribution of this work lies in the combination of rheological and conductivity measurements to deepen in the understanding of the heat transfer phenomenon in NF. The combination of rheological together with thermal conductivity measurements have permitted establishing the mechanisms of liquid layering and aggregate formation as the more relevant in the heat transfer of these silica fumed suspensions.

Rheological Fluids for Energy Absorbing Systems

2013 ◽  
Vol 440 ◽  
pp. 13-18 ◽  
Author(s):  
Marcin Leonowicz ◽  
Joanna Kozłowska ◽  
Łukasz Wierzbicki
Keyword(s):  
Magnetic Field ◽  
Carbonyl Iron ◽  
Volume Fraction ◽  
Loss Modulus ◽  
Shear Thickening ◽  
High Viscosity ◽  
Polypropylene Glycol ◽  
Magneto Rheological ◽  
Energy Absorbing ◽  
Protective Performance

Two types of non-Newtonian fluids, magneto rheological (MRF) and shear thickening (STF) fluids, respectively were chosen as candidates for energy dissipation study in smart body armour. A series of magneto rheological fluids was synthesized on a basis of synthetic oil and carbonyl iron. The shear modules for the MRF containing 75 wt% of carbonyl iron, obtained in a magnetic field of 230 kA/m were as follows: complex shear modulus G* - 1.2 MPa, storage modulus G-1.2 MPa and loss modulus G 0.35 MPa. The studies revealed also that the silica fumed, dispersed in polypropylene glycol or polyethylene oxide, demonstrates shear thickening properties. The best combination of the properties (high viscosity, obtained at high shear rate) represents the material composed of the silica fumed (SF) and PEO300. Change of the volume fraction of the SF and variation of the molecular weight of the oligomer enables tailoring of the STF properties. Ballistic tests revealed that the structures containing PE bags with MRF (in magnetic field) or STF can enhance the protective performance of body armours providing their flexibility.

Effect of Alumina Addition on the Rheological Behavior of Shear Thickening Fluids

2019 ◽  
Vol 798 ◽  
pp. 331-336
Author(s):  
Natnicha Nuampakdee ◽  
Sujarinee Sinchai ◽  
Chaiwut Gamonpilas
Keyword(s):  
Rheological Behavior ◽  
Colloidal Particles ◽  
Volume Fraction ◽  
Shear Thickening ◽  
Body Armor ◽  
Shear Stresses ◽  
Hard Material ◽  
Shear Rates ◽  
Shear Thickening Fluids ◽  
Alumina Addition

Shear thickening fluids (STF) have attracted much attention in many applications including body armor. In this study, suspensions of silica colloidal particles and polyethylene glycol fluid were prepared at varying volume fractions φ = 0.3 to 0.52 and their rheological behavior was investigated. It was found that the suspensions exhibited a Newtonian behavior for φ < 0.4, whilst a shear thinning followed by a thickening behavior could clearly be observed for φ > 0.4. Furthermore, the critical shear rates for the onset of shear thickening was found to decrease with increasing silica volume fraction but the corresponding critical shear stresses were independent of the volume fraction. To improve the ballistic protective performance, small amount of hard material particles, such as alumina, were added into the silica suspension of φ = 0.5. It was shown that the critical shear rates of the reinforced-STFs decreased with increasing volume fraction and decreasing alumina particle size. However, higher thickening ratio was observed for the alumina additive with agglomerated structure and this ratio increased with increasing alumina volume fraction.

scholarly journals Electrical conductivity of polymer/carbon nanofillers composites

2021 ◽  
Vol 2045 (1) ◽  
pp. 012008
Author(s):  
S Kostromin ◽  
S Bronnikov
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Graphene Oxide ◽  
Aspect Ratio ◽  
High Aspect Ratio ◽  
One Dimensional ◽  
Reduced Graphene ◽  
Multi Walled Carbon Nanotubes ◽  
Carbon Nanofillers ◽  
Walled Carbon Nanotubes

Abstract Using a broadband dielectric spectrometry we studied the effect of carbon nanofillers (CN) with various aspect ratio (fullerene C60, multi-walled carbon nanotubes (MWCNT), reduced graphene oxide (rGO) and hybrid rGO:MWCNT nanofillers) on the electrical conductivity of the polyazomethine-based nanocomposites. One-dimensional MWCNTs with high aspect ratio were shown to be the most effective CN for fabrication of polymer-based nanocomposites with enhanced electrical conductivity.

Effect of seawater ageing on interlaminar fracture toughness of carbon fiber/epoxy composites containing carbon nanofillers

2018 ◽  
Vol 37 (22) ◽  
pp. 1346-1359 ◽  
Author(s):  
Julio Alejandro Rodríguez-González ◽  
Carlos Rubio-González ◽  
José de Jesús Ku-Herrera ◽  
Lourdes Ramos-Galicia ◽  
Carlos Velasco-Santos
Keyword(s):  
Carbon Nanotubes ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Multiwalled Carbon Nanotubes ◽  
Composite Laminates ◽  
Double Cantilever Beam ◽  
Multiwalled Carbon ◽  
Reduced Graphene ◽  
Carbon Nanofillers ◽  
Carbon Fiber Epoxy

This work reports the influence of seawater ageing on the mode I and mode II interlaminar fracture toughness ([Formula: see text] and [Formula: see text]) of prepreg-based unidirectional carbon fiber/epoxy laminates containing carbon nanofillers. Double cantilever beam and end notched flexure specimens were fabricated from composite laminates containing multiwalled carbon nanotubes and/or reduced graphene oxide at their middle plane interface. Experimental results showed that the addition of carbon nanofillers moderately increased the [Formula: see text] and [Formula: see text] propagation of composite laminates before and after their immersion in seawater with respect to the reference laminate under dry condition. For double cantilever beam and end notched flexure specimens aged in seawater, it was observed that [Formula: see text] and [Formula: see text] increased by 57% and 13% for specimens with multiwalled carbon nanotube/reduced graphene oxide hybrid combination, 39% and 4% for specimens with multiwalled carbon nanotubes and 53% and 8% for specimens with reduced graphene oxide respectively, as a consequence of the plasticization effect of seawater immersion on the matrix. Fracture surface examination by scanning electron microscopy revealed interlaminar failure associated to mode I and mode II delamination and toughening mechanisms produced by the multiwalled carbon nanotubes and reduced graphene oxide at delaminated regions of composite laminates.

Sign in / Sign up

Export Citation Format

Share Document