Dielectric polymer composites with high dielectric constants and high thermal conductivity have many potential applications in modern electronic and electrical industry. In this study, three-phase composites comprising poly(vinylidene fluoride) (PVDF), barium titanate (BT) nanoparticles, and β-silicon carbide (β-SiC) whiskers were prepared. The superiority of this method is that, when compared with the two-phase PVDF/BT composites, three-phase composites not only show significantly increased dielectric constants but also have higher thermal conductivity. Our results show that the addition of 17.5 vol % β-SiC whiskers increases the dielectric constants of PVDF/BT nanocomposites from 39 to 325 at 1000 Hz, while the addition of 20.0 vol % β-SiC whiskers increases the thermal conductivity of PVDF/BT nanocomposites from 1.05 to 1.68 W m(-1) K(-1) at 25 °C. PVDF/β-SiC composites were also prepared for comparative research. It was found that PVDF/BT/β-SiC composites show much higher dielectric constants in comparison with the PVDF/β-SiC composites within 17.5 vol % β-SiC. The PVDF/β-SiC composites show dielectric constants comparable to those of the three-phase composites only when the β-SiC volume fraction is 20.0%, whereas the dielectric loss of the PVDF/β-SiC composites was much higher than that of the three-phase composites. The frequency dependence of the dielectric property for the composites was investigated by using broad-band (10(-2)-10(6) Hz) dielectric spectroscopy.

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Nanocolorants were successfully prepared via a modified miniemulsion polymerization process into which styrene, a polar monomer, crosslinkers, a highly hydrophobic solvent, dyes, and so forth were introduced. The obtained nanocolorants were nanocomposite entities in which a fraction of dye molecules attached to the crosslinked macromolecular chains and more dye molecules formed clustering because of the phase separation between the dye and polymer during the polymerization process and were further embedded in the interior of the crosslinked polymer because of the high hydrophobicity of the dyes. The effects of the polar monomers, the amounts of the dyes dissolved in styrene, and the polymer crosslinking, as well as the effects of the water-soluble and oil-soluble initiator, the amount of the surfactant, and the ultrasonic homogenization time, on the preserving fastness of the dyes in the polymeric matrix and the morphology and particle size distribution of the nanocolorants were studied.

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