Fabrication of Morphologically Controlled Composites with High Thermal Conductivity and Dielectric Performance from Aluminum Nanoflake and Recycled Plastic Package.

Polymer composites with high thermal conductivity are highly desirable for modern electronic and electrical industry because of their wide range of applications. However, conventional polymer composites with high thermal conductivity usually suffer from the deterioration of electrical insulation and high dielectric loss, whereas polymer composite materials with excellent electrical insulation and dielectric properties usually possess low thermal conductivity. In this study, combining surface-oxidized aluminum (Al) nanoflake and multilayer plastic package waste (MPW) by powder mixing technique, we report a novel strategy for polymer composites with high thermal conduction, high electrical insulation, and low dielectric loss. The resultant MPW/Al, MPW/Al400, and MPW/Al500 composites exhibited the maximum thermal conductivity of 4.8, 3.5, and 1.4 W/mK, respectively, which exceeds those of most of the corresponding composites reported previously. In addition, all the composites still have high insulation (<10-13 S/cm) and maintain dielectric loss at a relatively low level (<0.025). Such a result is ascribed to the formation of an insulating Al2O3 shell and the continuous three-dimensional filler network, which is revealed by Agari model fitting coefficient. The model of effective medium theory qualitatively demonstrates that the lower interfacial thermal resistances of the MPW/Al composite can also benefit the high thermal conduction. This interfacial engineering strategy provides an effectively method for the fabrication of polymer materials with high-performance thermal management.