Enhanced Electrical and Thermal Conductivities of Polymer Composites with a Segregated Network of Graphene Nanoplatelets

Abstract

Introducing a segregated network constructed through the selective localization of small amounts of fillers can be a solution to overcome the limitations of the practical use of graphene-based conductive composites due to the high cost of fillers. In this study, polypropylene composites filled with randomly dispersed GNPs and a segregated GNP network were prepared, and their conductive properties were investigated according to the formation of the segregated structure. Due to the GNP clusters induced by the segregated structure, the electrical percolation threshold was 2.9 wt% lower than that of the composite incorporating randomly dispersed GNPs. The fully interconnected GNP cluster network inside the composite contributed to achieving the thermal conductivity of 4.05 W/m∙K at 10 wt% filler content. Therefore, the introduction of a segregated filler network was suitable to simultaneously achieve excellent electrical and thermal conductivities at a low content of GNPs.

Vulcanization Bonded Natural Rubber-Aluminum by Chemically Modified Graphene Nanoplatelets-Epoxy Adhesive without Primer

“…A good dispersion of GNPs gave a shorter distance for the phonon transfer between each particle. It improves the tendency to form interconnected GNPs networks in the matrix, as reported by Kim et al, [32]. However, for the graphene agglomerates, the distances between each agglomerate are far apart, prone to forming a segregated network [32].…”

“…It improves the tendency to form interconnected GNPs networks in the matrix, as reported by Kim et al, [32]. However, for the graphene agglomerates, the distances between each agglomerate are far apart, prone to forming a segregated network [32]. This phenomenon caused a longer path for heat transfer.…”

Polymer Composites with Carbon Fillers Based on Coal Pitch and Petroleum Pitch Cokes: Structure, Electrical, Thermal, and Mechanical Properties

“…This can be explained by the dimensional factor, since graphene, MWCNT, and CB are nanofillers, for which the percolation threshold is always lower than for microfillers [ 78 , 79 ]. It was shown in [ 80 ] that a PP–graphene composite with a segregated filler structure has a percolation threshold value of 0.04 vol.%. At the same time, Zhao et al [ 76 ] found that UHMWPE composites with the segregated filler structure of reduced graphene oxide, natural graphite, and carbon nanofibers have the percolation threshold values in the range of 1–6 phr.…”

Segregated Conductive Polymer Composite with Fe3O4-Decorated Graphite Nanoparticles for Microwave Shielding

“…In these structures, the percolation threshold was reduced significantly by the selective location of the conductive fillers at the polymer granule interfaces and by the formation and connection of the conductive pathways to construct dense networks. For example, the electrical conductivity of the segregated GNPs–polypropylene composites improved by 20.79 S/m at a low filler content (1 wt%) [ 36 ]. A comparative study of the segregated and random CNT/polyethylene (PE) composites revealed that the electrical conductivity of 3 wt% CNTs loaded with the segregated composite was more than two orders higher than that of composites with random distribution fillers [ 37 ].…”