Mechanical, electrical and thermal properties of in-situ exfoliated graphene/epoxy nanocomposites

Depending on processing conditions, in-situ exfoliated graphite nanoplatelets (GNP) with low defect content and average aspect ratios up to 300-1000 and thicknesses of 5-17 nm could be produced by three roll milling (TRM). This paper focuses on the mechanical, electrical and thermal properties of in-situ GNP/epoxy nanocomposites, evaluated in terms of simple analytical models. Good mechanical reinforcement (160% increase in flexural modulus @ 4 wt.% GNP), electrical conductivity (∼10−2 S/m @ 3 wt.% GNP with a percolation threshold of 0.52 vol.%) and thermal conductivity (0.70 W m−1 K−1 @ 5 wt.% GNP) were obtained. The production of GNP-filled resins using TRM technology can potentially remove important cost barriers for GNP modified plastics, composites and coatings as compared to traditional multi-step solvent based exfoliation methods.