Thermal and dielectric behavior of epoxy composites filled with ceramic micro particulates

A mathematical correlation for the effective thermal conductivity of particulate-filled polymer composites is developed using the law of minimal thermal resistance and equal law of specific equivalent thermal conductivity. To validate this correlation, two sets of epoxy-based composites with micro-sized aluminum nitride and Al2O3 fillers (0-25vol%) are prepared by simple hand-lay-up technique. Thermal conductivities of these composites are measured using the Unitherm Model 2022 tester. These values are then compared with the values obtained from the proposed model and are found to be in fairly good agreement. Effects of fillers on other thermal properties (dimensional stability, glass transition temperature) and dielectric behavior of epoxy resin are also studied. Perkin-Elmer thermal mechanical analyzer and HIOKI-3532-50 Hi Tester Elsier Analyzer are used for this purpose. It is found that the measured properties of the composites are suitable for certain applications like electronic packaging and printed circuit boards.