Graphene: Prepared by High Speed Shearing-assisted Exfoliation and Its Application in Thermal Conductive Silicone

Graphene dispersion was produced by centrifugation after exfoliating the graphite in aqueous solutions containing sodium cholate as a surfactant with high speed shearing machine. The exfoliated graphene (thickness4 layers) showing large lateral size of around 2-3 m and high quality (I D /I G 0.15) was characterized by atomic force microscopy (AFM), transmission electron microscopy (TEM), and Raman spectroscopy. After freeze drying, Graphene was added in the silver-silicone rubber to produce a hybrid graphene-metal thermal conductive silicone rubber, and steady-state heat flow method was applied to study the thermal conductivity of the composite. It was found that as filler loading fraction of graphene increased from 0 to 3vol%, thermal conductivity of siliver-silicone rubber dramatically improved from 4.9 W/(mK)to 12.367 W/(mK). This result suggests that little-defect graphene with few layers prepared by exfoliating can significantly enhance the thermal conductivity of silicone rubber by synergy effect when combined with silver powder.