Effect of alumina shapes on dielectric properties of UV-cured epoxy acrylic composite with alumina

Abstract

Polymer-based composites with the advantages of ceramics and polymers exhibit high dielectric constant, good processing properties and low dielectric loss. The composites with a varied content of irregular alumina ( i -Al 2 O 3 ) filler were prepared by UV-cured epoxy acrylic (EA). Spherical alumina ( s -Al 2 O 3 ) was used as a filler to further investigate the effect of alumina (Al 2 O 3 ) shapes on dielectric properties of composites in the frequency range of 50 Hz–1 MHz. Fourier transform infrared spectroscopy proved that the UV-cured epoxy acrylic/alumina (Al 2 O 3 /EA) composites were successfully fabricated. Scanning electron microscopy demonstrated that i -Al 2 O 3 particles have superior homodispersion in the matrix. Through testing, for all samples, with the addition of Al 2 O 3 , the relative permittivity of composites increased as expected, and the dielectric loss decreased accordingly. These data show that the incorporation of i -Al 2 O 3 particles presents better properties when compared with s -Al 2 O 3 /EA, which indicates that i -Al 2 O 3 particles have more influence on the dielectric properties of the composites than those of s -Al 2 O 3 particles. According to Weibull distribution, the characteristic breakdown strength of the Al 2 O 3 /EA composites was obtained and the results suggested that the composites of i -Al 2 O 3 /EA exhibited better breakdown performance.