Effect of $\gamma$ irradiation and doping with silicon dioxide on the properties of polytetrafluoroethylene

We perform a comparative study of melting of polytetrafluoroethylene (PTFE) in its unmodified form, after irradiation, and after adding plant-derived silicon dioxide as an additive (content, 1%). Calculation of peak shapes on thermal capacity profiles within the theory of smeared phase transitions enable us to identify the structural changes and their features resulting from irradiation of PTFE and incorporation of the additive in it. $\alpha$-relaxation at the glass transition in our samples is studied by dynamic mechanical analysis.