Mechanism of thermal decomposition of peroxide radicals formed in polytetrafluoroethylene by γ‐ray irradiation

Thermal decomposition of polymer peroxide radicals formed in γ‐irradiated polytetrafluoroethylene, ∼CF2CF(OO·)CF2∼ (radical I) and ∼CF2CF2(OO∼) (radical II), was studied by mass spectral analysis of the gas evolved in comparison with their photolysis with ultraviolet light. In the thermal decomposition of radicals I and II, CO2 was the most abundant component, with smaller amount of CO, CF2O, and gases present. In the photolysis, CO instead of CO2 was the most abundant in the case of radical I, while in the case of radical II, CO2 was again the main product. When a labeled polymer peroxide radical, ∼CF2CF(18O‐18O·)CF2∼, was treated with heat or ultraviolet light, C18O16O was detected as a main component. In the treatment with ultraviolet light, a large amount of C18O comparable to that of C18O16O was also obtained. The mechanism of main‐chain scission of radicals I and II is discussed.