Synthesis of spherical silica/multiwall carbon nanotubes hybrid nanostructures and investigation of thermal conductivity of related nanofluids

2012 ◽  
Vol 549 ◽  
pp. 87-94 ◽  
Author(s):  
Mohammadali Baghbanzadeh ◽  
Alimorad Rashidi ◽  
Davood Rashtchian ◽  
Roghayeh Lotfi ◽  
Azadeh Amrollahi
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Multiwall Carbon Nanotubes ◽  
Hybrid Nanostructures ◽  
Spherical Silica ◽  
Multiwall Carbon

Anisotropic thermal conductivity of polypropylene composites filled with carbon fibers and multiwall carbon nanotubes

2014 ◽  
Vol 36 (11) ◽  
pp. 1951-1957 ◽  
Author(s):  
Ilya Mazov ◽  
Igor Burmistrov ◽  
Igor Il'inykh ◽  
Andrey Stepashkin ◽  
Denis Kuznetsov ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Carbon Fibers ◽  
Multiwall Carbon Nanotubes ◽  
Polypropylene Composites ◽  
Anisotropic Thermal Conductivity ◽  
Multiwall Carbon

Thermal conductivity of polypropylene-based composites with multiwall carbon nanotubes with different diameter and morphology

2014 ◽  
Vol 586 ◽  
pp. S440-S442 ◽  
Author(s):  
I.N. Mazov ◽  
I.A. Ilinykh ◽  
V.L. Kuznetsov ◽  
A.A. Stepashkin ◽  
K.S. Ergin ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Multiwall Carbon Nanotubes ◽  
Multiwall Carbon

Thermal conductivity and flammability of multiwall carbon nanotube/polyurethane foam composites

2016 ◽  
Vol 53 (2) ◽  
pp. 215-230 ◽  
Author(s):  
JJ Espadas-Escalante ◽  
F Avilés ◽  
PI Gonzalez-Chi ◽  
AI Oliva
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Polyurethane Foam ◽  
Fire Behavior ◽  
Multiwall Carbon Nanotubes ◽  
Propagation Speed ◽  
Interfacial Thermal Resistance ◽  
Multiwall Carbon Nanotube ◽  
Multiwall Carbon

The thermal conductivity and fire response of multiwall carbon nanotube/polyurethane foam composites are investigated for ∼45 kg/m3 foams with multiwall carbon nanotube concentrations of 0.1, 1, and 2 wt.%. The thermal conductivity of such nanocomposites shows a modest increase with increased multiwall carbon nanotube content, which is explained by a high value of interfacial thermal resistance, as predicted by existent thermal models. A strong correlation between multiwall carbon nanotube content, foam’s cellular morphology, and fire behavior was observed. The flame propagation speed increases with the addition of 0.1 wt.% multiwall carbon nanotubes and then reduces as the multiwall carbon nanotube content increases. The mass lost after flame extinction reduces with the addition of multiwall carbon nanotubes, suggesting an increased resistance to flame attack due the multiwall carbon nanotube presence.

scholarly journals Not Without Engineering

2001 ◽  
Vol 123 (02) ◽  
pp. 46-49 ◽  
Author(s):  
Arun Majumdar
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Room Temperature ◽  
Microelectromechanical Systems ◽  
Multiwall Carbon Nanotubes ◽  
University Of California ◽  
High Mechanical Strength ◽  
Optical Signals ◽  
The University ◽  
Multiwall Carbon

Recent experiments have shown that thermal conductivity of carbon nanotubes can be more than twice that of diamond. It should be noted that high mechanical strength often comes with high thermal conductivities. Recent experiments have shown that the thermal conductivity of carbon nanotubes can be as high as 3000 to 6000 W/m K at room temperature, which is more than twice that of diamond. It was recently shown by Alex Zettl and his group at the University of California, Berkeley that the relative motion between different shells of multiwall carbon nanotubes has some unique properties and can serve as excellent mechanical bearings that do not undergo any wear. Recent work has led to multifunctional probes, which, besides topography, can detect thermal, electrical, magnetic, and optical signals at nanoscales. The engineering challenge now is to develop microelectromechanical systems (MEMS)-based probes that integrate multiple functions on a single tip.

Improvement of the identification of multiwall carbon nanotubes carpet thermal conductivity by pulsed photothermal method

2012 ◽  
Vol 112 (9) ◽  
pp. 094322 ◽  
Author(s):  
E. Amin-Chalhoub ◽  
G. Wattieaux ◽  
N. Semmar ◽  
M. Gaillard ◽  
A. Petit ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Multiwall Carbon Nanotubes ◽  
Photothermal Method ◽  
Multiwall Carbon

Predicting the thermal conductivity of polypropylene-multiwall carbon nanotubes using the Krenchel model

2018 ◽  
Vol 25 (2) ◽  
pp. 383-388 ◽  
Author(s):  
Atheer M. Almasri
Keyword(s):  
Experimental Data ◽  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Polymer Matrix ◽  
Multiwall Carbon Nanotubes ◽  
Particulate Composite ◽  
Packing Factor ◽  
Three Phase ◽  
Cylindrical Tubes ◽  
Multiwall Carbon

AbstractThe thermal conductivity of particulate composite models is well documented in the literature. This paper attempts to fit the experimental data for the thermal conductivity of polymer nanocomposites to a three-phase Krenchel model. The use of this model is applicable for structures that consist of a polymer matrix, a nanofiller, and an interfacial layer around the nanoparticles. The effect of Kapitza’s thermal resistance is implemented in the model along with the assumption that the nanofillers are cylindrical and well connected to each other; however, no parameters related to any type of dispersants or the dispersion techniques are stated in the model. The results of the three-phase Krenchel model were validated using the experimental data of thermal conductivity of multiwall carbon nanotubes embedded in polypropylene matrix nanocomposites. It was found that the model was in good agreement with the experimental thermal conductivity data. Moreover, the results from the model showed that the filler geometrical packing factor was 0.75; consequently, the carbon nanotubes formed bundles of several cylindrical tubes. The length of the interface between the nanotubes and the polymer matrix was around 1 Å. Finally, the thermal conductivity of the composite bundle cylinder was 21.63 W/(m K).

scholarly journals Effects of MWCNTs on the Tensile Properties and Thermal Conductivity of BaTiO3 /Epoxy Nanocomposites

2020 ◽  
pp. 2226-2231
Author(s):  
Iman Ibrahem Nassif ◽  
Ban Mazin Al-Shabander
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Tensile Strength ◽  
Tensile Properties ◽  
Coupling Agent ◽  
Multiwall Carbon Nanotubes ◽  
Epoxy Nanocomposites ◽  
Pure Epoxy ◽  
Conductivity Enhancement ◽  
Multiwall Carbon

This research studied the effects of modified BaTiO3 (BT) nanoparticles with coupling agent γ-APS (0.5wt. %) on the tensile and thermal conductivity of epoxy nanocomposites with respect to content (0.25, 0.5, 0.75, 1, 3 and 5wt. %). Multiwall carbon nanotubes (MWCNTs) at different concentration (0.2, 0.4, 0.8 and 1 wt. %) were added to the BaTiO3/epoxy nanocomposites. The influence of MWCNTs on the tensile properties and thermal conductivity was investigated. The tensile strength and Young’s modulus of BaTiO3/epoxy nanocomposites film were increased at up to 3 wt. % of added BT, but  adding BT at more than 3 wt.% decreased the strength of epoxy. The tensile strength was increased with increasing MWCNTs content from 32 MPa for pure epoxy to the value 56.8 MPa for 1wt. % of MWCNTs content. The thermal conductivity of BaTiO3/epoxy nanocomposites improved with increase of BT content. At 3wt. % and 5wt. % of BaTiO3 the thermal conductivity of nanocomposites decreased. The increase of MWCNTs concentration from 0.2 wt. % to 1 wt. % resulted in a thermal conductivity enhancement.

A Microdevice for Measuring Thermophysical Properties of Nanowires and Nanotubes

2001 ◽  
Author(s):  
Li Shi ◽  
Philip Kim ◽  
Paul L. McEuen ◽  
Arunava Majumdar
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Silicon Nitride ◽  
Thermophysical Properties ◽  
Measurement Data ◽  
Thermal Conductance ◽  
Multiwall Carbon Nanotubes ◽  
Scanning Electron Micrographs ◽  
Experimental Proof ◽  
Multiwall Carbon

Abstract Nonotubes and nanowires are expected to have interesting thermophysical properties. For example, unusually high thermal conductivity and possibly low-temperature quantized thermal conductance have been predicted for carbon nanotubes (Berber et al. 2000). Meanwhile, other nanowires, such as Bi wires, may have suppressed thermal conductivity and high thermoelectric figure of merit (Volz and Chen). However, there lacks of experimental proof of these predictions because there are no established methods to measure the thermophysical properties of nanotubes and nanowires. Up to date, there are very few measurement data of thermal properties of nanotubes as well as nanowires (Hone et al. 1998, 1999, and 2000; Mizel et al., 1999). To provide a platform for concurrently measuring thermal conductivity and Seebeck coefficient of nanotubes and nanowires, a microdevice has been designed and used for measuring multiwall carbon nanotubes (MWCNs). Figure 1 shows the scanning electron micrographs of the microdevice. The device is a suspended structure consisting of two adjacent 10 μm × 10 μm silicon nitride (SiNx) membranes or islands suspended with three (or four) 200-μm long and 2 μm wide silicon nitride beams. One 30 nm thick, 200 nm wide, and 150 μm long platinum (Pt) heater/thermometer coil was built on each island. The heater coil is connected to contact pads with 200 μm long and 1μm wide Pt lines.

Energetic Ion Bombardment of Carbon Nanotubes

2015 ◽  
Vol 1743 ◽  
Author(s):  
Gregory A. Konesky
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Multiwall Carbon Nanotubes ◽  
High Strength ◽  
Ion Bombardment ◽  
Multiwall Carbon Nanotube ◽  
Self Healing ◽  
Energetic Ions ◽  
Multiwall Carbon

ABSTRACTCarbon Nanotubes (CNTs) exhibit exceptional properties in terms of high strength-to-weight, high electrical conductivity, and high thermal conductivity, and have been employed as a reinforcement in various composites and other materials. Their tolerance to radiation environments may be suggested by their response to energetic ion bombardment. We discuss the effects of argon ion bombardment of both thin and thick multiwall carbon nanotube films over a range of 4 to 11 keV at fluence levels up to the order of 1021 ions/cm2. While individual carbon atoms are readily displaced from a carbon nanotube by bombardment at these energies, these nanotubes also exhibit a self-healing capability. At moderate energies and fluence, if two or more carbon nanotubes are touching and an ion strikes this point, they heal together where a junction or cross-link between them is created and the nanotubes interpenetrate. Even though some of the properties of the carbon nanotubes may be degraded by ion bombardment at non-junction regions, we have demonstrated a bulk cross-linked thin film of randomly oriented multiwall carbon nanotubes with an isotropic thermal conductivity of 2150 W/m K. At higher energies and fluence, the carbon nanotubes appear to collapse and reform aligned parallel to the incoming ion bombardment trajectory, producing high aspect ratio tapered structures. These structures are, in general, fully dense, unlike the loosely packed random carbon nanotube array from which they originated. There is also a sharp transition at the base of these structures from the dense form to the loose-packed form, suggesting that these structures may inhibit further penetration of the energetic ions.

Boehmite Nanofibers as a Dispersant for Nanotubes in an Aqueous Sol

2018 ◽  
Author(s):  
Gen Hayase
Keyword(s):  
Carbon Nanotubes ◽  
Aspect Ratio ◽  
Aqueous Solutions ◽  
High Aspect Ratio ◽  
Multiwall Carbon Nanotubes ◽  
Multiwall Carbon ◽  
Nanotube Films

By exploiting the dispersibility and rigidity of boehmite nanofibers (BNFs) with a high aspect ratio of 4 nm in diameter and several micrometers in length, multiwall-carbon nanotubes (MWCNTs) were successfully dispersed in aqueous solutions. In these sols, the MWCNTs were dispersed at a ratio of about 5–8% relative to BNFs. Self-standing BNF–nanotube films were also obtained by filtering these dispersions and showing their functionality. These films can be expected to be applied to sensing materials.

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