Carbon black/graphite nanoplatelet/rubbery epoxy hybrid composites for thermal interface applications

Raza, Mohsin Ali; Westwood, Aidan; Stirling, Chris

doi:10.1007/s10853-011-5895-8

Cited by 23 publications

(16 citation statements)

References 32 publications

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“…The synergetic effect of GNPs and other nanofillers in improving the thermal conductivity of epoxy was also observed in the case of low total nanofiller loadings, i.e. 18 wt% total loading of GNPs and CB nanoparticles [14], 1wt% total loading of GNPs and MWCNTs [13], 2 wt% total loading of GNPs and MWCNTs [25] and ! 40 wt% total loading of GNPs and SWCNTs [4].…”

mentioning

confidence: 73%

“…In this work the maximum content of GNPs can further increase to 12 wt% and accordingly the maximum thermal conductivity of silane treated GNP/ epoxy composites can reach nearly 6.3 times that of epoxy, exceeding that of silane treated COOH-MWCNT/epoxy composites, 2.9 times that of epoxy, with 6 wt% COOH-MWCNTs. It is known that a strong interface increases the coupling effect of fillers with matrix, damps the phonons' vibrational amplitude at interface, and thus decreases the efficiency of fillers as thermal conductors in matrix [34], moreover, a layer of coupling agent on the fillers acts as a barrier to the phonon transport between filler particles [14], thus silane treatment of GNPs might be adverse to the improvement of thermal conductivity of the GNP/ epoxy composites. However, the functionalized outside layers of GNPs by silane treatment can promote better dispersion of GNPs in epoxy matrix and facilitate the transport of phonons from GNPs to matrix.…”

Section: Characterizationmentioning

confidence: 99%

“…40 wt% total loading of GNPs and SWCNTs [4]. The addition of 0-D CB nanoparticles helped to increase the thermal conductivity of GNP/epoxy composites by improving the dispersion of GNPs, preventing the settling of GNPs and bridging the gaps among 2-D GNPs [14]. Long and tortuous 1-D CNTs were used to bridge adjacent 2-D GNPs as well as inhibit the aggregation of GNPs, resulting in a high contact area between GNP/CNT structures and epoxy matrix and thus a more efficient percolating nanofiller network with significantly reduced thermal interface resistances, consequently the thermal conductivity of epoxy filled with a mixture of GNPs and CNTs surpassed that of epoxy filled with pure GNPs or CNTs [4,13,25].…”

mentioning

confidence: 99%

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Improving the thermal conductivity of epoxy resin by the addition of a mixture of graphite nanoplatelets and silicon carbide microparticles

Zhou¹,

Cheng²,

Wang³

et al. 2013

Express Polym. Lett.

111

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Graphene nanosheet (GNS), a single layer of hexagonally arrayed sp 2 -bonded carbon, has attracted increasing attention recently due to its excellent thermal, electrical and mechanical properties. However, manufacturing GNS-filled composites has been very challenging due to the difficulties in large-scale production of GNSs and their dispersion in matrices. GNSs tend to form irreversible agglomerates or even restack to form graphite through van der Waals interactions during the processing of bulk-quantity GNSs, especially in the drying process [1]. Carbon nanotube (CNT), another type of widely studied and applied high-performance carbon-based nanofiller, also has great challenges in composite applications especially due to its expensive production cost. Instead of trying to discover easier large-scale processes for GNSs or lower cost processes for CNTs, an alternative type of carbon-based nanofiller with comparable properties, which can be produced more easily and cost-effectively in large quantities, has also recently been emphasized. Abstract. In this work, an alternative type of carbon-based nanofiller, graphite nanoplatelets (GNPs) with comparable properties, easier and lower-cost production, were used to improve the thermal conductivity of an epoxy. By adding 12 wt% GNPs or 71.7 wt% silicon carbide microparticles (micro-SiCs) to epoxy, the thermal conductivity reached maxima that were respectively 6.3 and 20.7 times that of the epoxy alone. To further improve the thermal conductivity a mixture of the two fillers was utilized. The utilized GNPs are characterized by two-dimensional (2-D) structure with high aspect ratio (~447), which enables GNPs effectively act as heat conductive bridges among 3-D micro-SiCs, thus contributes considerably to the formation of a more efficient 3-D percolating network for heat flow, resulting in higher thermal conductivity with relatively lower filler contents which is important for decreasing the density, viscosity and improving the processability of composites. A thermal conductivity, 26.1 times that of epoxy, was obtained with 7 wt% GNPs + 53 wt% micro-SiCs, thus not only break the bottleneck of further improving the thermal conductivity of epoxy composites but also broaden the applications of GNPs.

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mentioning

confidence: 73%

Section: Characterizationmentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Improving the thermal conductivity of epoxy resin by the addition of a mixture of graphite nanoplatelets and silicon carbide microparticles

Zhou¹,

Cheng²,

Wang³

et al. 2013

Express Polym. Lett.

111

View full text Add to dashboard Cite

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“…These total filler contents from 14 to 18 wt.% were selected to produce hybrid composites because dispersions with higher loadings could not be easily coated as thin at a strain rate of 0.5 mm min -1 [26,27]. These composites were also tested, with cured matrix, as adhesives according to ASTM standard D5470 on a thermal contact resistance measurement rig to quantify their performance as TIMs.…”

Section: Methodsmentioning

confidence: 99%

Effect of boron nitride addition on properties of vapour grown carbon nanofiber/rubbery epoxy composites for thermal interface applications

Raza

Westwood

Stirling

et al. 2015

Composites Science and Technology

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This work is focused on developing an epoxy-based hybrid composite using BN and VGCNF, with the main motivation of producing thermally conducting but electrically insulating composite thermal interface materials (TIMs). Various compositions of BN/VGCNF/rubbery epoxy hybrid composites were developed by 3-roll milling. The thermal conductivity of hybrid composites increases with increasing VGCNF content and electrical conductivity decreases with increasing BN content. SEM showed that BN inclusion inhibits VGCNF contacts resulting in more electrically insulating composites. Compression testing showed that BN inclusion produced stiffer composites than those produced with VGCNFs at equivalent loading. The thermal contact resistance of 6 wt.% BN/8 wt.% VGCNF/rubbery epoxy composite was 3.36 × 10 -5 m 2 .K/W at a bond line thickness of 18 m. Thermal contact resistance measurements showed that hybrid composites can offer better interfacial thermal transport at thick bond lines and this improves with increasing VGCNF content due to increased thermal conductivity imparted by VGCNF.

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“…7. The 6 wt.% CB/12 wt.% GNP-5/rubbery epoxy hybrid composite coating cannot be applied as thinly as 6 wt.% CBP/rubbery epoxy composite coatings due to the significantly increased viscosity of the hybrid coating [19]. However, bondline thicknesses of ~60 µm were easily achieved and the potential exists to decrease this thickness further by increasing the pressure between the interfaces.…”

Section: Thermal Contact Resistance Of Cb/gnp/rubbery Epoxy Hybrid Comentioning

confidence: 99%

Comparison of carbon nanofiller-based polymer composite adhesives and pastes for thermal interface applications

2015

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Graphite nanoplatelets (GNP), carbon black (CB) and carbon nanotubes are extensively researched to produce thermal interface materials (TIMs). This work reports comparison of interfacial thermal conductance (ITC) of carbon nanofiller-based polymer composite adhesives and pastes. The results show that total thermal contact resistance (TTCR) of GNP/rubbery epoxy composite was the same as that of an equivalent glassy epoxy composite. Although CB-based rubbery epoxy and silicone composites can be applied as thin bondlines, their TTCRs were significantly higher than GNP/rubbery epoxy. GNPs incorporation into CB/rubbery epoxy composite improves the ITC of the CB/rubbery epoxy composites but the performance of CB/GNP/rubbery epoxy was inferior to GNP/rubbery epoxy. The thermal paste of GNP/polyetheramine had TTCR of 4.8 × 10 -6 m 2 .K/W which is comparable to commercial TIMpaste. The paste produced with silicone had relatively poor ITC versus that prepared with polyetheramine. The paste having smaller particle sized GNPs offers lower TTCR than that prepared with large sized GNPs. The GNP/rubbery epoxy adhesives produced from precursor pastes gave the lowest TTCRs in comparison with the other adhesives. This study suggests that GNPs offer potential for enhancing ITC of TIMs and that ITC of adhesives depends on fillers' thermal conductivity and their interfacial contact with substrates.

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Carbon black/graphite nanoplatelet/rubbery epoxy hybrid composites for thermal interface applications

Cited by 23 publications

References 32 publications

Improving the thermal conductivity of epoxy resin by the addition of a mixture of graphite nanoplatelets and silicon carbide microparticles

Improving the thermal conductivity of epoxy resin by the addition of a mixture of graphite nanoplatelets and silicon carbide microparticles

Effect of boron nitride addition on properties of vapour grown carbon nanofiber/rubbery epoxy composites for thermal interface applications

Comparison of carbon nanofiller-based polymer composite adhesives and pastes for thermal interface applications

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