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

Abstract

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.

Effect of volume-fraction dependent agglomeration of nanoparticles on the thermal conductivity of nanocomposites: Applications to epoxy resins, filled by SiO2, AlN and MgO nanoparticles

“…It is observed that heat conductivity first increases linearly with the degree of agglomeration, reaches a maximum at the percolation threshold and finally decreases. The raising of conductivity with size (at nanoscale) was confirmed by many authors [46][47][48][49][50][51] in the case of epoxy resin with various fillers and by Prasher et al [31,52] in the case of nanofluids.…”

Melt processing and characterisation of polyamide 6/graphene nanoplatelet composites

“…Thermal conductivity as well as other thermal properties depend on properties of both the additives and the matrix [17,35]. At low wt%, the fillers in LLDPE are in isolated states.…”

Development and optimisation of phase change material-impregnated lightweight aggregates for geopolymer composites made from aluminosilicate rich mud and milled glass powder

“…Carbon based fillers have been used to successfully improve the thermal performance of the PCM itself [20] and resins [21]. Results show that with the addition of 7 wt% of carbon fibres to PCM, the thermal conductivity can be quadruplicated [22] while the addition of 71.7 wt% of silicon carbide to epoxy can improve its thermal conductivity by 20 times [23].…”