In this presentation, I will discuss synthesis of new isotactic PP polymers containing various polar groups (including OH, NH2, NH3+Cl-) and cross-linkers, which provide significant benefits to the electric energy storage applications. The current state-of-the-art BOPP capacitors exhibitmany desirable properties (high pulsed, high power density, low dielectric loss, cost effective, and reliability), but only delivering low energy storage density (2 J/cc). The increase of energy density without altering other desirable properties, especially the low dielectric loss property, can significantly expand PP to a wide range of energy storage applications. Our synthesis scheme involves a direct metallocene-mediated copolymerization using specific iso-specific catalysts and suitable comonomers. Several functional PP copolymers containing few mol% polar groups show a dielectric constant of above 4 (double of BOPP)�which is independent on a wide range of temperatures (between -20 and 100o C) and frequencies (between 100 and 1M Hz)�and high breakdown strength >600 MV/m. They are potential to deliver an energy density 2-3 times of BOPP after an applied electric field 600 MV/m, without showing significant increase of energy loss.  Computer simulation sheds light on the role played by OH groups and the trapped H2O molecules. In addition, the cross-linked PP dielectrics show good mechanical strength and thermal stability, exhibit high breakdown strength (>800 MV/m) and narrow breakdown distribution.

Synthesis of functional polypropylene polymers containing polar groups and network structure for dielectric and energy storage applications

246th National Meeting (2013)

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