Dielectric response of aramid fiber-reinforced PEEK

The application of dielectric spectroscopy to aramid fiber-reinforced poly(ether ether ketone) (PEEK) was studied. The effect of the fiber on the dielectric response was examined for both amorphous and crystalline PEEK overwide temperature and frequency ranges. The specific effect of the fibers in the crystalline PEEK was revealed in shifting the α and β process to a higher temperature. The unique effect of the fibers was expressed by a significantly higher activation energy and lower dielectric strength for the α relaxation, reflecting a higher constraint level imposed by the fiber.