Fabrication of Permittivity Graded Epoxy Resin with Non-Uniform Dispersion of Alumina Fillers by a Centrifugal Procedure

The centrifugal method was successfully applied to fabricate functionally graded materials with different profiles of gradient in permittivity (i.e., e-FGMs) from an alumina/epoxy mixture. Gradient of the number density, packing fraction, and size of the dispersed alumina fillers was confirmed. Non-spherical and spherical alumina fillers were employed to fabricate e-FGMs, where, conditions of the centrifugal process for both fillers were quite differentiated from each other. The gradient of filler dispersion was intentionally regulated by changing not only conditions of the centrifugal process, but also the size distribution and shape of fillers.