SYNCHROTRON-RADIATION (5-50 EV) INDUCED DEGRADATION OF FLUORINATED POLYMERS

The photochemistry of solid, free-standing films of poly(tetrafluoroethylene) (PTFE) and poly(hexafluoropropylene-tetrafluoroethylene) (FEP) was investigated by monitoring the neutral photodesorption products produced upon irradiation with synchrotron radiation (5-50 eV). CF3, C2F5, C3F5, C3F7, and C4F7 were the predominant species observed in the mass spectra of the irradiated polymers. Oligomers at least as large as 293 amu (C7F12) were also detected. Distinct differences are observed in the photodesorption yields and time responses of the yields based on the energy of the initial excitation. An edge jump at 22 eV in the photon-stimulated desorption spectra of both PTFE and FEP films is assigned to the ionization of the C(2s) states of the polymers. The energy dependence of the photodesorption yields is accounted for by considering two separate reaction pathways.