Ionic Liquid-Modified Copper for the Enhanced Thermal Conductivity and Mechanical Properties of Epoxy Resin/Expanded Graphite Composites

In this study, diglycidylether of bisphenol A (DGEBA)/expanded graphite (EG)/copper (Cu) powder composites with high thermal conductivity were prepared for use as thermal interface materials. To construct an excellent thermally conductive network, the Cu surface was modified using the ionic liquid 1-ethyl-3-methyl imidazolium dicyanamide. In addition, the effect of the Cu content on the thermal conductivity, thermal stability, flexural properties, impact strength, and morphologies of the DGEBA/EG/Cu composites was investigated. The results indicated that the addition of 10 wt % Cu increased the thermal conductivity of the composites from 7.35 to 9.86 W/(m·K). Conversely, the thermal stability of the composites decreased with the addition of Cu. The flexural strength and impact strength of the composites increased from 27.9 MPa and 0.81 kJ/m