High temperature polymer dielectrics from the ring opening metathesis polymerization (ROMP)

Recently much research has focused on the development of new polymer dielectric materials to fabricate capacitors for use in the inverters of next generation hybrid electric vehicles (HEV). The capacitors used in HEVs inverters will be required to operate at 150°C, 600 V, and have an energy density of 0.9 J/cm³. Polymer based thin film capacitors are ideal for this application due to their relatively high energy density, low cost, and high dielectric breakdown strength. We have polymerized several ring strained monomers using ring opening metathesis polymerization (ROMP) and have identified a promising polymer system based on N-Phenyl-7-oxanorbornene-5,6-dicarboximide (PhONDI). Several of its copolymers with norbornene have been evaluated for possible use as next generation high temperature polymer dielectrics in thin film capacitors. The copolymers were cast into thin films and Au electrodes were deposited on the polymer film. The electrical properties were evaluated as a function of temperature. The polymer system exhibited very good high temperature dielectric properties and is potentially useful as a high temperature capacitor dielectric.