The relationship between the thermal/electrical conductivity enhancement in graphite nanoplatelets （GNPs） composites and the properties of filling graphite nanoplatelets is studied. The effective thermal and electrical conductivity enhancements of GNP-oil nanofluids and GNP-polyimide composites are measured. By taking into account the particle shape, the volume fraction, the thermal conductivity of filling particles and the base fluids, the thermal and electrical conductivity enhancements of GNP nanofluids are theoretically predicted by the generalized effective medium theory. Both the nonlinear dependence of effective thermal conductivity on the GNP volume fraction in nanofhiids and the very low percolation threshold for GNP-polyimide composites are well predicted. The theoretical predications are found to be in reasonably good agreement with the experimental data. The generalized effective medium theory can be used for predicting the thermal and electrical properties of GNP composites and it is still available for most of the thermal/electrical modifications in two-phase composites.
The relationship between thermal/electrical conductivity enhancement in asphalt-matrix mixtures and the properties of filling conductive particles is studied. The thermal properties with filling the carbon fiber, graphite conductive particles in asphalt-matrix mixtures are investigated. Based on the generalized effective medium theory （ EMT ）, the effective thermal and electrical conductivity of carbon fiber/asphalt and graphite/asphalt composites are theoretically elucidated. The theoretical results are found to be in reasonably well agreement with the experimental data. Moreover, the theoretical and experimental results show that the large-aspect-ratio shape of particles can help to achieve a large enhancement of effective conductivity, and the use of disk-like high conductivity particles can limit the additive contents for preserving the volumetric properties and mechanical properties of asphalt composites. The generalized effective medium theory model can be used for predicting the thermal and electrical properties of asphaltmatrix composites, which is still available for most of the thermal/electrical modifications in two-phase composites.
