Effect of crystallinity and morphology on dielectric properties of PEEK at elevated temperature

Poly(aryl ether ether ketone) (PEEK) is one of the primary candidates for a high temperature capacitor dielectric as a result of its outstanding mechanical strength and thermal stability. However, its breakdown strength is unsatisfactory (~400 MV/m) and high field (>100 MV/m) volumetric resistivity at elevated temperature is largely unknown. In this work, the inter-relationship among crystallinity, morphology, breakdown strength, and volumetric resistivity of PEEK at elevated temperature is studied in order to gain insight to factors which adversely affect breakdown. This paper presents preliminary results of the study.