中文摘要：

研究了石墨纳米片复合物的电、热传输性质的增强与添加的石墨纳米片热导率、电导率之间的关系．测量了石墨纳米片／油纳米流体、石墨纳米片／聚酰亚胺复合物的有效热导率和电导率增强．通过考虑颗粒形状、体积分数、添加颗粒的热导率和基质性质，依据发展的有效媒质理论，理论预测了石墨片纳米流体的电导率、热导率增强．解释了石墨纳米片的添加量和增强之间的非线性关系，同时还阐明了小体积份数下石墨纳米片复合物的渗流闽值．理论计算结果与实验结果吻合．发展的有效媒质理论不仅适用于预测石墨纳米片复合物的电导率、热导率性质，而且还适用于所有两相复合体系的电导率、热导率改性．

英文摘要：

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.