ScienceDirect ® is a registered trademark of Elsevier B.V. ScienceDirect ® is a registered trademark of Elsevier B.V. PVA with lower degree of polymerization showed higher crystallinity. There are, however, other researches that estimate that this number is exaggerated, and that the in-plane thermal conductivity of graphene at … Graphene’s heat conductivity can be used in many ways, including thermal interface materials (TIM), heat spreaders, thermal greases (thin layers usually between a heat source such as a microprocessor and a heat sink), graphene-based nanocomposites, … molecules Article Thermal Conductivity of Defective Graphene Oxide: A Molecular Dynamic Study Yi Yang 1, Jing Cao 2, Ning Wei 1,*, Donghui Meng 3, Lina Wang 3, Guohua Ren 3, Rongxin Yan 3,* and Ning Zhang 1,* 1 College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling 712100, China; yang_yi@nwafu.edu.cn 2 State Key Laboratory of Eco-hydraulics in … GO/PVA composites are successfully prepared owing to their high compatibility via hydrogen bonds between PVA and GO. However, its thermal conductivity, one of the most important and fundamental physical properties, is still less known. When the total amount of filler was fixed 50 wt.% while changing the amount of MWCNTs, a maximum thermal conductivity was obtained with the addition of about 0.36 wt.% of MWCNTs in the filler. Too high a MWCNT concentration led to increased phonon scattering, which in turn led to decreased thermal conductivity. https://doi.org/10.1016/j.carbon.2012.07.029. The electrical conductivity (σ) of RGO/PS composites with different RGO concentrations at room temperature shows a percolation behavior with the percolation threshold of ∼0.25 vol. GO is well dispersed in PVA aqueous solution, and GO/PVA composite films are easily prepared with various GO contents. Because the particle concentration of GO was sufficient (∼50 wt.%) for the formation of a conducting path, the so-called percolation threshold insisted by other authors as the critical concentration of graphene or GO having a high aspect ratio exists below 0.1 vol.%, the thermal conductivity was much higher than that of the pure polymer matrix (∼0.2 W/mK). We use cookies to help provide and enhance our service and tailor content and ads. The thermal transport properties of the composites were maximized at 50 wt.% of filler due to fixed pore volume fraction in filtrated GO cake. Abstract. Estimates were given in terms of phonon mean free paths for the reduction in thermal conductivity by interior defects due to scattering. The in-plane thermal conductivity of this prepared film was 13.42 W m −1 K −1, whereas that in the cross-plane direction was 0.69 W m −1 K −1. Thermal conductivity of all samples was measured at three … © 2017 Elsevier Ltd. All rights reserved. Their temperature-dependent electrical conductivity follows … The polar functionality on the GO surface allowed the permeation of the epoxy resin due to a secondary interaction between them, which allowed the fabrication of a composite containing a high concentration of this hybrid filler. Phonon conductive path along the thickness direction is achieved by silica beads. The thermal properties of graphene oxide containing hydroxyl and epoxy functional groups were studied using non-equilibrium molecular dynamics to understand the thermal transport phenomena involved and the structure factors limiting heat conduction. Therefore, graphene and similar materials with exceptional thermal conductivity may hold an enormous potential for this kind of applications. In this study, GO is added as a filler in the polyvinyl alcohol (PVA) matrix for the purpose of improving thermal conductivity. Well dispersed composite was prepared via hydrogen bonds between PVA and GO. The author reports an experimental study of electrical and thermal transport in reduced graphene oxide (RGO)/polystyrene (PS) composites. By continuing you agree to the use of cookies. In addition, the increase of grafting density improves the enhancement of … Thermally conductive graphene oxide (GO)–multi-wall carbon nanotube (MWCNT)/epoxy composite materials were fabricated by epoxy wetting. Thermal conductivity of graphene was theoretically estimated to be as high as 5300 Wm −1 K −1 and experimentally in the range of 3080–5150 Wm −1 K −1, and it is much higher than Al (200 Wm −1 K −1), Au (300 Wm −1 K −1), and Cu (400 Wm −1 K −1) as general thermal conductive fillers. It is found that the high‐temperature annealing dramatically increases the in‐plane thermal conductivity, K, of the films from ≈3 to ≈61 W m −1 K −1 at room temperature. Graphene oxide due to its functional groups has low thermal and electrical conductivity than reduced GO. Copyright © 2012 Elsevier Ltd. All rights reserved. https://doi.org/10.1016/j.polymer.2017.09.055. The measured storage modulus was higher than that of the solvent mixed composite because of the insufficient interface between the large amount of filler and the epoxy. Improvement of thermal conductivity attributed to GO dispersion and crystallinity. A single layer of suspended graphene has one of the highest reported thermal conductivities exceeding 5,000 W m −1 K −11,2 but is not practical to use as a heatsink material. The thermal conductivities of the polymer composites investigated in terms of GO content concentration, GO degree of oxidation, PVA degree of polymerization, and silica-bead packing in the GO/PVA composite. For example, at a grafting density of ∼0.0144/Å 2, the interfacial thermal conductance increases to 144 ± 15 MW/m 2 K from 56 ± 4 MW/m 2 K of the pristine graphene/polymer interface. Herein, we review the thermal properties of graphene, including its specifi c heat and thermal conductivity (from diffusive to … The thermal conductivity of PVA depends on its degree of crystallinity. ScienceDirect ® is a registered trademark of Elsevier B.V. ScienceDirect ® is a registered trademark of Elsevier B.V. The polar functionality on the GO surface allowed the permeation of the epoxy resin due to a secondary interaction between them, which allowed the fabrication of a composite containing a high concentration of this hybrid filler.
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