Construction of highly aligned graphene-based aerogels and their epoxy composites towards high thermal conductivity

2019 ◽  
Vol 7 (38) ◽  
pp. 11783-11789 ◽  
Author(s):  
Ying Li ◽  
Wei Wei ◽  
Ying Wang ◽  
Nabil Kadhim ◽  
Yuan Mei ◽  
...  

The oxidation degree of the graphene layers affects the self-assembly behaviors of GA during directional freezing, which govern the thermal contact resistance among the layers and the final thermal conductivity of the GA-based epoxy composites.

Small ◽  
2021 ◽  
pp. 2102128
Author(s):  
Taehun Kim ◽  
Seongkyun Kim ◽  
Eungchul Kim ◽  
Taesung Kim ◽  
Jungwan Cho ◽  
...  

Author(s):  
Odne S. Burheim ◽  
Jon G. Pharoah ◽  
Hannah Lampert ◽  
Preben J. S. Vie ◽  
Signe Kjelstrup

We report the through-plane thermal conductivities of the several widely used carbon porous transport layers (PTLs) and their thermal contact resistance to an aluminum polarization plate. We report these values both for wet and dry samples and at different compaction pressures. We show that depending on the type of PTL and the existence of residual water, the thermal conductivity of the materials varies from 0.15 W K−1 m−1 to 1.6 W K−1 m−1, one order of magnitude. This behavior is the same for the contact resistance varying from 0.8 m2 K W−1 to 11×10−4 m2 K W−1. For dry PTLs, the thermal conductivity decreases with increasing polytetrafluorethylene (PTFE) content and increases with residual water. These effects are explained by the behavior of air, water, and PTFE in between the PTL fibers. It is also found that Toray papers of differing thickness exhibit different thermal conductivities.


2015 ◽  
Vol 19 (4) ◽  
pp. 1369-1372 ◽  
Author(s):  
Zhe Zhao ◽  
Hai-Ming Huang ◽  
Qing Wang ◽  
Song Ji

To explore whether pressure and temperature can affect thermal contact resistance, we have proposed a new experimental approach for measurement of the thermal contact resistance. Taking the thermal contact resistance between phenolic resin and carbon-carbon composites, cuprum, and aluminum as the examples, the influence of the thermal contact resistance between specimens under pressure is tested by experiment. Two groups of experiments are performed and then an analysis on influencing factors of the thermal contact resistance is presented in this paper. The experimental results reveal that the thermal contact resistance depends not only on the thermal conductivity coefficient of materials, but on the interfacial temperature and pressure. Furthermore, the thermal contact resistance between cuprum and aluminum is more sensitive to pressure and temperature than that between phenolic resin and carbon-carbon composites.


2006 ◽  
Vol 306-308 ◽  
pp. 775-780
Author(s):  
Tung Yang Chen

Effective thermal conductivities of composites consisting of curvilinearly anisotropic inclusions with Kapitza thermal contact resistance between the constituents are considered. We show that the effect of these curvilinearly anisotropic inclusions can be exactly simulated by certain equivalent isotropic or transversely isotropic inclusions. Three different micromechanical models are employed to estimate the effective thermal conductivity of the composite. Interestingly, all these methods result in the same simple, closed-form expression.


2018 ◽  
Vol 27 (6) ◽  
pp. 096369351802700
Author(s):  
Tao Huang ◽  
Yimin Yao ◽  
Gang Zhang ◽  
Fanling Meng

With the development of polymer-filled composites, the demand of high thermal conductivity materials is much attractive than ever. However, the process of a common method to improve thermal conductivity of composites is considerably complicated. The aim of this study is to investigate thermal conductivity of epoxy filled silver nanoparticle deposited aluminum nitride nanoparticles with relatively convenient process. We found that the thermal conductivities of composites filled with AlN/Ag nanoparticles are effectively enhanced, which is enormously increased from 0.48 Wm-1K-1(1.88 vol%) to 3.66 Wm-1K-1 (19.54 vol%). This can be ascribed to the bridging connections of silver nanoparticle among aluminum nitride nanoparticles. In addition, the thermal contact resistance of the epoxy composites filler with AlN/Ag nanoparticles is decreased, which is proved by the fitting measured thermal conductivity of epoxy composite with one physical model. We believe the finding has great potential for any microelectronic application.


Author(s):  
Ehsan Sadeghi ◽  
Scott Hsieh ◽  
Majid Bahrami

Accurate information on heat transfer and temperature distribution in metal foams is necessary for design and modeling of thermal-hydraulic systems incorporating metal foams. The analysis of this process requires determination of the effective thermal conductivity as well as the thermal contact resistance (TCR) associated with the interface between the metal foams and adjacent surfaces/layers. In the present study, a test bed that allows the separation of effective thermal conductivity and thermal contact resistance in metal foams is described. Measurements are performed in a vacuum under varying compressive loads using ERG Duocel aluminum foam samples with different porosities and pore densities. Also, a graphical method associated with a computer code is developed to demonstrate the distribution of contact spots and estimate the real contact area at the interface. Our results show that the porosity and the effective thermal conductivity remain unchanged with the variation of compression in the range of 0 to 2 MPa; but TCR decreases significantly with pressure due to an increase in the real contact area at the interface. Moreover, the ratio of real to nominal contact area varies between 0 to 0.013, depending upon the compressive force, porosity, and surface characteristics.


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