The relationship between dielectric properties and the preparation method of nano-SiO 2 /epoxy composite

In this paper, the effect of preparation method on the permittivity and dielectric loss of nano-SiO 2 /epoxy composites was studied. The nano-SiO 2 was dispersed into epoxy resin by three methods, which were “Ultrasonic Dispersion Method”, “High-speed Mixer Method” and “Sol-gel method”. The composites with 1wt%, 2wt%, 3wt% and 4wt% loading were made respectively. To compare the influence of the preparation methods to the permittivity and dielectric loss characteristics, dielectric spectra of the nanocomposites at the frequency range of 106–100 Hz were measured by Novo-control system. The results showed that the permittivity of nanocomposites made by the “High-speed Mixer Method” is lower than that made by the other methods. With the loading of nano-SiO 2 increased, the permittivity of nanocomposites increased then decreased, and reached its maximum at the 3wt% loading. The dielectric loss of nanocomposites is higher than the pure epoxy resin when the frequency is under 1 kHz and as the frequency exceeds 1 kHz, the dielectric loss of the nanocomposites is lower than the pure epoxy resin.