Correlation between chemical, thermal and dielectric properties of gamma-irradiated PTFE thin films

Polytetrafluoroethylene (PTFE) is widely used in industrial applications, specifically in the space industry as a thermal blanket and electrical wire insulation for spacecraft, aircraft and demanding applications. Controling the change in structural, thermal, and dielectric properties of PTFE films due to degradation processes induced by ionizing radiation is extremely important to ensure the safe operation of the material. This study contributes to the field by investigating the correlation between the degradation behavior and properties of irradiated PTFE thin films under different doses of 60 Co gamma radiation. During the experimental work, the physico-chemical and thermal properties of PTFE were studied by infrared spectroscopy and differential scanning calorimetry, respectively. The experimental results showed changes in the thermal properties of irradiated PTFE with a significant increase in the degree of crystallinity revealed upon irradiation and a decrease in the molecular weight of the polymer in the amorphous regions. The dielectric spectroscopy data showed that higher crystallinity goes with an increase of the real permittivity and loss factor. These results are discussed in terms of the formation of crystallized regions in amorphous regions, which increases the heterogeneity of the structure after irradiation exposure.