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

Abstract

Abstract Thermal decomposition of polymer peroxide radicals formed in γ‐irradiated polytetrafluoroethylene, ∼CF 2 CF(OO·)CF 2 ∼ (radical I) and ∼CF 2 CF 2 (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, CO 2 was the most abundant component, with smaller amount of CO, CF 2 O, and gases present. In the photolysis, CO instead of CO 2 was the most abundant in the case of radical I, while in the case of radical II, CO 2 was again the main product. When a labeled polymer peroxide radical, ∼CF 2 CF( 18 O‐ 18 O·)CF 2 ∼, was treated with heat or ultraviolet light, C 18 O 16 O was detected as a main component. In the treatment with ultraviolet light, a large amount of C 18 O comparable to that of C 18 O 16 O was also obtained. The mechanism of main‐chain scission of radicals I and II is discussed.