Material propertiesNovel syndiotactic polystyrene/BaTiO3-graphite nanosheets three-phase composites with high dielectric permittivity

Novel three-phase composites were prepared by embedding graphite nanosheets (GNs) and BaTiO3 nanoparticles into syndiotactic polystyrene (sPS) matrix via a solution blending and flocculation method. The dependences of electric and dielectric properties of the resultant sPS/BaTiO3-GNs composites on volume fractions of GNs (fGNs) and frequency were investigated. The percolation theory was employed to explain the electric and dielectric behavior of sPS/BaTiO3-GNs composite. It was found that the sPS/BaTiO3-GNs composite showed an obvious insulator-conductor transition with a much low percolation threshold of fGNs = 1.44 vol%. The dielectric permittivity of sPS/BaTiO3-GNs composite reached as high as 51.8 at 100 Hz at percolation threshold, which was about 18 and 7 times higher than that of pure sPS and sPS/BaTiO3 composite, respectively.