Texture, transport and mechanical properties of graphite nanoplatelet/silicone composites produced by three roll mill

Thermally conducting and highly compliant composites for thermal interface applications were developed by dispersing graphite nanoplatelets (GNPs) in silicone polymer using a three-roll mill process. X-ray diffraction and electron microscopy showed that the roll mill produces composites with better dispersion of GNPs than previously achieved by speed and mechanical mixing. The roll mill also allows production of a composite at 25 wt.% GNP loading. The thermal conductivities of the composites reached 1.03 and 3.15 W/m K at 8 and 25 wt.% of GNPs, respectively, compared to 0.17 W/m K for silicone. Compression testing showed that the composites’ moduli increase by 1.5 times up to 20 wt.% loading but the strength and strain to failure decrease. The Shore hardness was similar or slightly lower to that of silicone. The composites are thus promising alternatives to the commercial thermal interface materials currently available.