A series of 0-3 metal oxide-polyolefin nanocomposites are synthesized via in situ olefin polymerization, using the following single-site metallocene catalysts: C2-symmetric dichloro[rac-ethylenebisindenyl]-zirconium(IV),Me 2Si( tBuN)(η 5-C 5Me 4)TiCl 2, and(η 5-C 5Me 5)TiCl 3 immobilized onmethylaluminoxane (MAO)-treated BaTiO 3, ZrO 2, 3-mol %-yttria-stabilized zirconia, 8-mol%-yttria-stabilized zirconia, sphere-shaped TiO2 nanoparticles, and rod-shaped TiO 2 nanoparticles. The resulting compositematerials are structurally characterized via X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), 13C nuclear magnetic resonance (NMR) spectroscopy, and differential scanning calorimetry (DSC). TEM analysis shows that the nanoparticles are well-dispersed in the polymer matrix, with each individual nanoparticle surrounded by polymer. Electrical measurements reveal that most of these nanocomposites have leakage current densities of ∼10 -6-10 -8 A/cm 2; relative permittivities increase as the nanoparticle volume fraction increases, withmeasured values as high as 6.1. At the same volume fraction, rod-shaped TiO 2 nanoparticle-isotactic polypropylene nanocomposites exhibit significantly greater permittivities than the corresponding sphere-shaped TiO 2 nanoparticleisotactic polypropylene nanocomposites. Effective medium theories fail to give a quantitative description of the capacitance behavior, but do aid substantially in interpreting the trends qualitatively. The energy storage densities of these nanocomposites are estimated to be as high as 9.4 J/cm 3.
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)
- Materials Chemistry