Influence of Gamma Radiation on Electrical Conduction of Polyethylene Terephthalate (PET) at Ambient Temperature

Abstract

The electrical conduction in polyethylene terephthalate (PET) exposed to a gamma radiation dose of 150 kGy was investigated in the applied field range from 4 to 36 kV=mm. Samples were irradiated in air at room temperature by means of a 60 Co gamma source at a dose rate of approximately 42 Gy=min. The electrical properties of virgin and irradiated materials were examined by charging and discharging current measurements. The current decays with time can be represented according to an inverse power law. The changes of dielectric behavior after irradiation were attributed to scission effects.

Electron Transport Mechanisms in Polyethylene Terephthalate Membranes

“…The re-plotting of the curves J(E) in the coordinates Ln(J/E 2 ) vs E −1 , corresponding to the Fowler-Nordheim model [15][16][17][18], led to their linearization in weak, but not in strong, electric fields, in line with theory. Moreover, replotting gives values of the barrier height (less than 10 9 eV) that are physically too low, indicating that the Fowler-Nordheim model is also inappropriate for describing the J(E) dependences in the studied temperature range, as confirmed in works [9][10][11][12].…”

“…The mechanisms for conduction in PET films have mainly been studied above room temperature, up to the crystallization temperature (of the order of 400 K) for amorphous samples and at higher temperatures for crystalline samples. The results of these studies, presented in papers [9][10][11][12], show the activation characteristics of the temperature dependences for electrical conductivity. However, these works give contradictory results for activation energies, which vary from 0.4 to 2.58 eV depending on the type of metallic electrodes.…”

“…These contradictions can be attributed to the different relative content of the amorphous and crystalline phases in the PET samples studied, as well as to the different types and quality of electrical contacts used in electrical measurements. In works [11,12] the studied I(V ) characteristics of pristine PET films in the temperature range of 300−400 K were described based on the Schottky injection model. On the other hand, work [10] denies the applicability of this model, leaning towards the validity of the space-charge-limited current (SCLC) model.…”

Charge transport behavior in gamma‐ray irradiated poly(ethylene terephthalate) estimated by surface potential decay

“…N. Belkahla et al have demonstrated the influence of gamma‐ray irradiation on electrical conduction in PET. It was proposed that the increase in direct current after the irradiation was due to the chain scission of the macromolecules induced by the irradiation [12]. Although researches have been conducted to understand the change in mechanical, thermal or dielectric property of PET caused by gamma‐ray irradiation, the charge transport behaviour has been rarely focused on.…”