Al₂O₃/BaTiO₃/PUA:一种具有高介电常数,低介电损耗的介电复合材料

Polyurethane acrylate (PUA) dielectric composites were prepared by UV curing,in which alumina (Al₂O₃) and barium titanate (BaTiO₃) were used as fillers to construct a single or multi-component system. Hoping to provide reliable experimental data and theoretical references for 3D printed dielectric functionally graded materials, the microstructure and viscosity of compo-sites with different fillers were analyzed. Moreover, the influence of filler types and the filling amount on the dielectric properties of composites were studied. Fourier transform infrared (FTIR) spectroscopy proved that the UV-cured composites were successfully fabricated, the addition of fillers did not change the chemical structure of the matrix and the two phases about filler and matrix were physically combined. Scanning electron microscopic (SEM) demonstrated that the filler particles present a homogeneous dispersity in the matrix. Furthermore, the addition of BaTiO₃ increased the viscosity of the system to a greater extent. Through testing, in a one-component system, the dielectric loss of Al₂O₃/PUA composites with the filler volume fraction of 50% was lowest to 0.036 9 at 50 Hz, which was 40.9% lower than that of pure PUA. As the filling amount of BaTiO₃ was 25%, the relative permittivity of BaTiO₃/PUA composites was up to 22.7, which was 241% higher than that of pure PUA. In the two-component system, as the volume fraction of Al₂O₃ and BaTiO₃ were 30% and 10% respectively, the relative permittivity of the composite increased to 13.0, which was almost doubled compared to PUA, and the dielectric loss was reduced by 18.8% compared to the composite with 10% BaTiO₃, indicating that the co-introduction of BaTiO₃ and Al₂O₃ could depress the dielectric loss while increasing the relative permittivity of the composites.