Supported Metallocene Catalysis for In Situ Synthesis of High Energy Density Metal Oxide Nanocomposites

The 0−3 metal oxide−isotactic polypropylene nanocomposites are synthesized via in situ propylene polymerization using the C 2 -symmetric metallocene catalyst dichloro[ rac -ethylenebisindenyl]zirconium(IV) (EBIZrCl 2 ) immobilized on methylaluminoxane (MAO)-treated barium titanate (BaTiO 3 ) or titanium dioxide (TiO 2 ) nanoparticles. The composite materials are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and 13 C nuclear magnetic resonance (NMR) spectroscopy. It is shown that the nanoparticles are homogeneously dispersed in the polyolefin matrices. Electrical measurements reveal nanocomposite leakage current densities of ∼10 -6 to 10 -9 A/cm 2, permittivities as high as 6.1, and breakdown strengths of ∼4 MV/cm. Energy densities are estimated to be as high as 9.4 J/cm 3 .