Structural and dielectric properties of hot-pressed poly(vinylidene fluoride)-based composites

The characterization of ceramic/polymer composites was performed on zinc oxide/poly(vinylidene fluoride) – ZnO/PVDF and barium titanate/poly(vinylidene fluoride) composites with varying filler concentration in order to evaluate the main interactions responsible for the composite dielectric behavior. The materials, poly(vinylidene fluoride) and its composites, were melt-blended using a two-roller mixer and then hot-pressed. The permittivity of composites was enhanced compared with that of the pure poly(vinylidene fluoride) with the addition of 20 w/w% of ZnO particles. However, samples with 40 or 60 w/w% of ZnO registered a diminution in the real permittivity values which was connected to particle-matrix adhesion problems. On the other hand, barium titanate composites presented a more homogeneous morphology with less presence of voids and a better adhesion between the filler and the polymer, where real permittivity increased with the addition of barium titanate particles.