Thermal and electrical conductivity improvement in epoxy resin with expanded graphite and silver plating

To improve the thermal and electrical conductivity of diglycidylether of bisphenol-A (DGEBA), expanded graphite (EG) was added to the DGEBA matrix and the EG surface was silver plated. The effect of EG content on the thermal and electrical conductivity, thermal property, flexural properties, impact strength, and morphology of the DGEBA/EG composites was investigated. The silver plating on the EG surface was confirmed via high-resolution scanning electron microscopy, energy-dispersive X-ray spectrometry, and X-ray photoelectron spectroscopy. The results indicate that the thermal conductivity of the DGEBA/EG composites containing 60 wt% of EG was 7.35 W/m·K, which was 42 times higher than that of the pristine DGEBA. In addition, the thermal conductivity of the DGEBA/EG composites further increased from 7.35 to 9.49 W/m·K after the EG surface was silver plated. The electrical conductivity of the DGEBA/EG composites increased from 0 to 0.62 S/cm with the addition of 60 wt% of EG and further increased to 0.78 S/cm after silver plating of the EG surface.