Thermal Conductivity Enhancement of Graphene Epoxy Nanocomposite (original) (raw)
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Enhanced thermal conductivity of graphene nanoplatelets epoxy composites
Materials Science-Poland
Efficient heat dissipation from modern electronic devices is a key issue for their proper performance. An important role in the assembly of electronic devices is played by polymers, due to their simple application and easiness of processing. The thermal conductivity of pure polymers is relatively low and addition of thermally conductive particles into polymer matrix is the method to enhance the overall thermal conductivity of the composite. The aim of the presented work is to examine a possibility of increasing the thermal conductivity of the filled epoxy resin systems, applicable for electrical insulation, by the use of composites filled with graphene nanoplatelets. It is remarkable that the addition of only 4 wt.% of graphene could lead to 132 % increase in thermal conductivity. In this study, several new aspects of graphene composites such as sedimentation effects or temperature dependence of thermal conductivity have been presented. The thermal conductivity results were also com...
physica status solidi (a), 2016
We analyze the geometric effects of two different carbon fillers on the enhancement of the thermal conductivity of carbon‐epoxy composites. This study compares the thermal properties of composites containing graphite powder (2‐dimensional) and carbon nanofibers (1‐dimensional) incorporated in an industrial epoxy. Calculations using the generalized effective medium model were also used to examine the effect of the geometry and aspect ratio of the carbon filler. Experiments show that at a filler volume fraction loading of 0.10, the effective thermal conductivity of the composites was improved up to eightfold for carbon nanofiber and threefold for graphite in comparison to the neat epoxy. The superior performance of the carbon nanofiber composite is due to the larger aspect ratio of nanofiber which allows greater overlap between neighboring particles. However, this greater overlap also results in the composite becoming prohibitively viscous at low filler volume fractions. In graphite c...
Journal of Composite Materials, 2017
A series of selectively reduced graphite oxide was prepared by thermal reduction of graphite oxide at different annealing temperatures and used as fillers to enhance thermal conductivity of epoxy composites. The reduction degree of selectively reduced graphite oxide increases with annealing temperature changing from 600℃ to 1000℃. The out-of-plane thermal conductivity ( Κo) of selectively reduced graphite oxide/epoxy composites is remarkably higher than that of graphite oxide/epoxy. For the selectively reduced graphite oxide obtained at 1000℃, Κo reaches 0.674 W/m·K when filler content is 5.4 wt%, which is 450% of pure epoxy. The enhanced Κo can be attributed to the better dispersion of selectively reduced graphite oxide in epoxy and their edges overlap to form effective thermal conductive paths in epoxy matrix. However, the achieved thermal conductivity enhancement is still comparatively lower than that of selectively reduced graphite oxide with higher reduction degree, since the i...
Applied Physics A
Applications of polymer-based nanocomposites continue to rise because of their special properties such as lightweight, low cost, and durability. Among the most important applications is the thermal management of high density electronics which requires effective dissipation of internally generated heat. This paper presents our experimental results on the influence of graphene, multi-walled carbon nanotubes (MWCNTs) and chopped carbon fibers on wear resistance, hardness, impact strength and thermal conductivity of epoxy resin composites. We observed that, within the range of the experimental data (epoxy resin + 1, 3, 5 wt% of graphene or 1, 3, 5 wt% MWCNT or 10, 30, 50 wt% carbon fibers), graphene-enhanced wear resistance of the nanocomposites by 75% compared to 50% and 38% obtained for MWCNT and carbon fiber composite, respectively. The impact resistance of graphene nanocomposite rose by 26% (from 7.3 to 9.2 J/m 2) while that of MWCNT nanocomposite was improved by 14% (from 7.3 to 8.2 J/m 2). The thermal conductivity increased 3.6-fold for the graphene nanocomposite compared to threefold for MWCNT nanocomposite and a meager 0.63-fold for carbon fiber composite. These enhancements in mechanical and thermal properties are generally linear within the experimental limits. The huge increase in thermal conductivity, especially for the graphene and MWCNT nanocomposites makes the composites readily applicable as high conductive materials for use as heat spreaders and thermal pads.
Role of solvent in enhancement of thermal conductivity of epoxy/graphene nanocomposites
2022
In this work, we demonstrate that dimethylformamide (DMF) leads to better dispersion of graphene nanoplatelets relative to acetone, leading to higher thermal conductivity epoxy-graphene nanocomposites. Uniform dispersion of graphene nanoparticles into epoxy is critical for achieving high thermal conductivity epoxy-graphene nanocomposites. Uniform dispersion of graphene nanoplatelets can improve thermal contact with polymer leading to higher thermal conductivity of the composite. Organic solvents typically lead to efficient dispersion of graphene into the epoxy matrix. In this study, we compare the effect of two organic solvents, dimethylformamide (DMF) and acetone, in terms of their efficiency in dispersing graphene into the epoxy matrix and their effect on enhancing thermal conductivity of the composite. While the effect of solvents on mechanical properties of polymer-graphene nanocomposites has been studied, their effect on thermal conductivity is not well understood. In this stud...
Graphite Nanoplatelets Composite Materials: Role of the Epoxy-System in the Thermal Conductivity
Journal of Materials Science and Chemical Engineering, 2015
Polymers typically have intrinsic thermal conductivity much lower than other materials. Enhancement of this property may be obtained by the addition of conductive fillers. In this research, epoxy nanocomposites with exfoliated graphite nanoplatelets are prepared and characterized. The chosen approach requires no surface treatment and no sophisticated equipments allowing one to produce composites on a pilot scale. A significant increase of the thermal conductivity with the increasing of the graphite fillers content is nevertheless observed on 4 mm thick specimens. Our results viewed in the latest scientific findings suggest that the choice of resin is an important parameter to move towards composite materials with high thermal conductivity.
Model Approach to Thermal Conductivity in Hybrid Graphene–Polymer Nanocomposites
Molecules
The thermal conductivity of epoxy nanocomposites filled with self-assembled hybrid nanoparticles composed of multilayered graphene nanoplatelets and anatase nanoparticles was described using an analytical model based on the effective medium approximation with a reasonable amount of input data. The proposed effective thickness approach allowed for the simplification of the thermal conductivity simulations in hybrid graphene@anatase TiO2 nanosheets by including the phenomenological thermal boundary resistance. The sensitivity of the modeled thermal conductivity to the geometrical and material parameters of filling particles and the host polymer matrix, filler’s mass concentration, self-assembling degree, and Kapitza thermal boundary resistances at emerging interfaces was numerically evaluated. A fair agreement of the calculated and measured room-temperature thermal conductivity was obtained.
A three-roll mill processing technique was used to disperse graphene nanoplatelets into epon 828 epoxy system. As a first step of this research, processing of graphene/epoxy nanocomposites was explored with different weight percentages of graphene. After establishing an optimal and repeatable process to achieve good electrical properties, the materials were tested for thermal conductivity and mechanical properties. The xGnP-25 graphene nanoplatelet supplied by XG Science Inc. was used; the graphene average diameter was 25 lm and thickness was 6–10 nm. Mechanical mixing, sonication and three-roll mill dispersion techniques were investigated to disperse graphene in epon 828 epoxy. The study showed that the three-roll dispersion is effective, repeatable and potentially scalable to disperse graphene into epoxy to increase the electrical conductivity. The weight percentage of graphene used ranged from 0.5 to 5.0. Percolation threshold of graphene was found to be 1.0 wt%. Through-the-thickness or volume electrical conductivity increased by nine log cycles, thermal conductivity doubled and fracture toughness increased by one-third for 1.0 wt% addition of graphene to epon 828. However, the mechanical properties remained almost unchanged.