Dielectric behavior of polyetheretherketone (PEEK) using TSDC technique

Abstract

The dielectric relaxation behavior of Polyetheretherketone (PEEK) has been investigated by using thermally stimulated discharge current (TSDC) technique. The dependence of TSDC characteristics of PEEK on poling temperature (T P ) [50-200°C], poling field (E P ) [200-500 kV/cm], storage time (t S ) [2-120 hrs] and various thicknesses 25 μm, 50 μm and 75 μm have been investigated in the temperature range [60-230°C]. The TSDC spectra shows a prominent maxima around glass transition temperature (T g ) i.e. at 143°C named as α-peak and the other peak is observed around 200°C named as β-peak. The α-dipolar relaxation is taking place because of the movement of ketone (>C 00) dipoles linked to the main chain. The β-peak is attributed to the space charges. It is observed that the magnitude of α-peak increases with the increase in poling field. The peak current and area under the α-peaks are found to be diminished with the increase of storage time (t s ) for electrets. The amplitude of α-peak decreases with the increase in thickness. The activation energies for PEEK sample at different conditions in the present work are found to be 0.38 eV-1.70 eV. The values of activation energy (U) and preexponential factor (C o ) for α-relaxation are determined using Bucci plot method and support the nature of the relaxations.

Swift Heavy ion irradiation effects on dielectric constant and dielectric loss in poly (ether ether ketone) (PEEK)

“…The dielectric loss peak shown in Fig. 2 starts around 140 o C, that is also confirmation of the α-relaxation due to polar group attached to the main chain of PEEK [10]. The value of dielectric constant for amorphous and semi crystalline the PEEK below 150 o C reported by Huo and Cebe is 3.26 [9] and our results are in agreement with their results.…”

“…At the temperature above 150 o C, there is a sudden and sharp rise in dielectric constant with temperature and that can be linked to onset of α-relaxation. The existence of this relaxation process is also confirmed by TSDC analysis of PEEK and supports that this relaxation is taking place because of the movement of ketone (> C=0) dipoles linked to the main chain [10]. In the polymers where the dipoles are directly attached to main chain, movement of the dipoles will depend on the ability of main chain segment to move.…”

New method to analyze dielectric relaxation processes: a study on polymethacrylate series

“…At highest temperatures, only one process is observable, known as the αβ process. 10 Other techniques such as DSC, 11 thermally stimulated depolarization currents (TSDC) 12,13 and mechanical spectroscopy 14 have also been used to confirm and support the evidence collected by dielectric spectroscopy.…”

Preparation and characterization of transparent polyetherketone

“…PEK-T underwent a quick decomposition when the temperature is higher than 400 C. The glass transition temperature (T g ) of the prepared PEK-T was tested by differential scanning calorimetry (DSC). As shown in Figure 2b, PEK-T has a glass transition around 172 C. For comparison, the glass transition temperature of conventional PEEK is 143 C. [68][69][70] The results indicated that the polymer PEK-T with the new structure has sufficient high temperature resistance to meet many commercial applications.…”