Crystallinity and dielectric properties of PEEK, poly(ether ether ketone)

The dependence of specific dielectric properties of polymers on their fundamental molecular parameters was investigated as part of a study involving HV insulation in spacecraft systems. As part of an effort to understand the causes of dielectric breakdown, this investigation focused on the effect of polymer morphology on the electrical characteristics of a poly (ether ether ketone) (PEEK), a high temperature insulating thermoplastic. Amorphous PEEK was thermally annealed to produce a range of crystallinities, and its dielectric properties were measured. As the crystalline/amorphous ratio of the polymer increased, the dielectric breakdown strength was reduced. The electrical conductivity of the material was also shown to decrease with increasing crystallinity. The effect on the permittivity was inconclusive.<>