Dielectric Properties and Thermal Conductivity of Poly(vinylidene fluoride)-Based Composites with Graphite Nanosheet and Nickel Particle.

The nickel (Ni) particles and graphite nanosheet (GNS) filled poly(vinylidene fluoride) (PVDF) composites were prepared by solution blending and hot-press processing in the magnetic field. The influence of Ni particles and GNS fillers for the structure, morphology, AC conductivity, dielectric properties and thermal conductivity of composites was investigated. The results showed that the β -phase crystals of PVDF matrix was increased obviously. The AC conductivity, dielectric constant and dielectric loss of PVDF/Ni/GNS composite reached to 10-9 s/cm, 62 and 0.39 when the filler loading was 11 wt.% at 102 Hz, respectively. At the ratio of 15 wt.% filler, the AC conductivity of PVDF/Ni/GNS composite was vastly improved to 10-6 s/cm, however, the dielectric constant increased to ~80 and dielectric loss was over 600 at 10² Hz. By comparing the dielectric performance of PVDF/Ni/GNS, PVDF/Ni and PVDF/GNS composites, it is found that the parallel arrangement of the filler conduces to improve the dielectric properties of the composites. Furthermore, the thermal conductivity of PVDF/Ni/GNS composites increased with the increase of Ni and GNS contents and the value raised to over 0.5 W/mK when filler loading was 15 wt.%.