Design and Preparation of Halogenated Polynorbornenes via Systematic Structural Variation for Energy Storage up to 200°C

High temperature flexible dielectric polymers are critical for rapid high-power needs under extreme electric fields and temperature. This work relates to the design and systematic study of halogenated polynorbornenes and the relationship that the dielectric properties have on changing the halogen from fluorine to chlorine to bromine. Further, in addition to changing the halogen systematically, the position of the halogen has been varied as well in going from the ortho to para position on a pendant phenyl derivatized imide. Variation of halogen position results in a change in energy required for a phenyl group rotation. The correlation between size, free volume, energy of rotation and position of halogen addition on the structural, thermal, and dielectric properties of the polymer will be reported. In this work, changing the pendent halogens (F, Cl, Br) at para and ortho position on the benzene increases the glass transition temperature from ~220 to 245°C, discharge energy density energy density changes from 5 to 6.2J/cm³, dielectric constant range ~ 2.8-3.0 @100Hz frequency and charging-discharging electric field ~-625-700MV/m @200°C. The energy of rotation, free volume and loss also increase in going from fluorine to bromine at the para position. As a result, electrical breakdown and loss phenomena are better understood for designing novel high temperature polymer dielectrics with high energy density and low loss at elevated temperature.