Fabrication and Characterization of Thermally Conductive Polymer Nanocomposites Including Ferromagnetic Metal Core and Oxide Shell Particles Tied with Silicon Layer

Abstract

The thermal conductivity of the three-component composites was much higher than that of the two-component composites containing unimodal particles. The formation of the thermal conducting alumina shell layer leads to an extremely enhanced conductivity, higher than that of the polymer composites without thermal conducting shell layer. The calculated thermal conductivity of the nanostructured shell layer in the core-shell particles was reduced rather significantly by the phonon scattering at the boundaries of the nanocrystallites with a size of less than phonon mean free path. It is attributed to the enhancement of thermal contact conductance between polymer and thermally conducting shell layer with silicon tie layer in the polymer nanocomposite sheets including of the FeCr core-alumina conductive shell. Thus, the enhanced thermal conductivity of the three-component composites was found to be due to the excellent thermal contact conductance of the shell layer between the core particle surface and continuous polymer medium. Conclusively, the thermal conductivity of the three-component composite sheets with nanostructured shell layer was well-predicted from the modified Pal model by considering the phonon scattering.