Dielectric characterization of polymer-ceramic nanocomposites

Polymer-ceramic nanocomposites for high power applications are being developed at the University of Missouri-Columbia. Several polymers and epoxies have been investigated as candidate matrix materials. Two of the candidate matrix materials were used to create composites with several loading factors of nanoparticles. The matrix materials and composites are characterized through measurements of the dielectric constant and loss over a wide range of frequencies, dielectric strength in pulsed high voltage conditions, and scanning electron microscopy. Two test stands have been implemented for measurement of the complex dielectric permittivity in two frequency ranges of interest. Measurements from 100 kHz to 30 MHz are performed using parallel-plate methods and a precision LCR meter. Measurements from 200 MHz up to 4.5 GHz are performed by utilizing network analysis. The nanocomposites were also characterized for dielectric breakdown. A test stand was built to characterize the nanocomposites under pulsed conditions. Dielectric strength measurements were conducted with a pulse generator capable of up to nearly 160 kV. The 10%-90% voltage risetime in pulsed dielectric strength measurements was typically 60 ns. A summary of the composite materials, diagnostic methods, and preliminary results are reported. The dielectric constant, dielectric loss, and dielectric strength are reported for several matrix material candidates. Preliminary results of the first nanocomposite materials are also presented.