DC dielectric breakdown characteristics of mesoporous-alumina/epoxy composite

This paper presents an attempt to derive the dc dielectric breakdown characteristics of polymer composite filled with the metal oxide particle which has mesoporous structure. Mesoporous-alumina/epoxy composite was fabricated by compounding epoxy resin and mesoporous-alumina particles which had the micrometric particle-diameter and the nanometric pore-size. Measurement of the specific gravity of mesoporous-alumina/epoxy composites indicated that the porosity of mesoporous-alumina particle in the epoxy matrix was higher than that of nonporous-alumina particle. From the breakdown test with using McKeown electrode, DC breakdown strength of mesoporous-alumina/epoxy composites was obtained, which was compared with DC breakdown strength of the nonporous-alumina/epoxy composites. These results suggested that the nanometric pore with wormhole structure inside mesoporous particle could not be critical defect for DC dielectric breakdown characteristics in low filler concentration.