Thermal Expansion of Graphene Composites

Isolated graphene sheets were achieved by graphite intercalation and charge-induced exfoliation. The resultant graphene oxide sheets were incorporated into polymer composites and thermal expansion was investigated by a thermo-mechanical analyzer. The test results indicated that inclusion of graphene into composites resulted in low coefficients of thermal expansion (CTEs), and increasing graphene fraction reduced CTEs more significantly. The 5 wt % graphene oxide-based composite shows 31.7% reduction below the glass transition temperature. Preliminary measurement of thermal conductivity also indicated that graphene composites significantly improved the thermal conductivity of polymer matrix. Thermal conductivity of 5% graphene composites showed about 4-fold increment in comparison to the polymer matrix. This finding will provide a solid foundation for graphene-enabled thermal management in microelectronics.