Main-Chain Scission and ESR Spectra of Irradiated Polytetrafluoroethylene Oxide

The chief effect of ionizing radiation on polytetrafluoroethylene oxide (PTFEO) is to induce main-chain scission. The ESR spectrum of the irradiated polymer in vacuum consists of two components. The stable spectrum is attributed to the –CF2–CF2–O. and –O–ĊF–CF2–O– radicals. The former radical decays slowly at room temperature, the latter is unchanged even after several weeks. The unstable spectrum disappears in a few hours and its structure is uncertain. Tentatively this spectrum is assigned to the –O–CF2–CF2. radical. Admission of air to the irradiated polymer gives rise to a spectrum formed of a symmetric singlet assigned to –CF2CF2–OO. radical and an asymmetric signal to –CF–CF2–O–. – O–O·A Gfracture=1.8 has been calculated from viscosity data.