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-Al2O3) filler were prepared by UV-cured epoxy acrylic (EA). Spherical alumina (s-Al2O3) was used as a filler to further investigate the effect of alumina (Al2O3) 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 (Al2O3/EA) composites were successfully fabricated. Scanning electron microscopy demonstrated that i-Al2O3 particles have superior homodispersion in the matrix. Through testing, for all samples, with the addition of Al2O3, the relative permittivity of composites increased as expected, and the dielectric loss decreased accordingly. These data show that the incorporation of i-Al2O3 particles presents better properties when compared with s-Al2O3/EA, which indicates that i-Al2O3 particles have more influence on the dielectric properties of the composites than those of s-Al2O3 particles. According to Weibull distribution, the characteristic breakdown strength of the Al2O3/EA composites was obtained and the results suggested that the composites of i-Al2O3/EA exhibited better breakdown performance.
Highlights
Polymer-based insulation materials with high dielectric constant have been widely applied in the electrical and electronic field,& 2019 The Authors
Sudha et al [19] reported on nanostructured amorphous alumina-modified polycarbonate composites, which showed the enhancement of dielectric constant over five times of pure polycarbonate and the loss decreased by 13.3% with 5 wt % Al2O3 as a filler and suggested that the composites could serve as a better electrical insulator in capacitors, printed circuit boards (PCBs) and electronic packaging industries [20]
The chemical structures of the uncured epoxy acrylic (EA) and the cured Al2O3/EA composites were characterized by FTIR spectroscopy, as depicted in figure 2
Summary
Polymer-based insulation materials with high dielectric constant have been widely applied in the electrical and electronic field,. Sudha et al [19] reported on nanostructured amorphous alumina-modified polycarbonate composites, which showed the enhancement of dielectric constant over five times of pure polycarbonate and the loss decreased by 13.3% with 5 wt % Al2O3 as a filler and suggested that the composites could serve as a better electrical insulator in capacitors, printed circuit boards (PCBs) and electronic packaging industries [20]. In this paper, the bisphenol A epoxy acrylic, diluent and photoinitiator were mixed in proper proportions to form the polymer matrix, two shapes of alumina particles sourced commercially were incorporated to enhance the relative permittivity of polymer materials, and cured by exposure to UV light. The dispersity of alumina particles in the matrix was observed by scanning electron microscopy (SEM), and the effect of alumina shapes on the dielectric properties of composites was investigated
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