Thermal and Electrical Properties of Hybrid Composites with Graphene and Boron Nitride Fillers

TL;DR

This study explores how hybrid composites with graphene and boron nitride fillers can be engineered to optimize thermal and electrical conductivities for advanced thermal interface materials.

Contribution

It demonstrates the ability to tune thermal and electrical properties of composites by varying filler ratios with geometrically similar fillers, contrasting prior studies with dissimilar geometries.

Findings

Thermal conductivity increased by a factor of 15 to 35.

Electrical conductivity increased by several orders of magnitude.

Filler ratio effectively controls composite properties.

Abstract

We report on the thermal and electrical properties of hybrid epoxy composites with graphene and boron nitride fillers. The thicknesses, lateral dimensions, and aspect ratios of each filler material were intentionally selected for geometric similarity to one another, in contrast to prior studies that utilized dissimilar filler geometries to achieve a "synergistic" effect. We demonstrate that the electrically-conductive graphene and electrically-insulating boron nitride fillers allow one to effectively engineer the thermal and electrical conductivities of their resulting composites. By varying the constituent fraction of boron nitride to graphene in a composite with ~44% total filler loading, one can tune the thermal conductivity enhancement from a factor of x15 to x35 and increase the electrical conductivity by many orders of magnitude. The obtained results are important for the development of next-generation thermal interface materials with controllable electrical properties necessary for applications requiring either electrical grounding or insulation.