An ESR study of irradiated poly(tetrafluoroethylene-co-perfluoropropyl vinyl ether) (PFA)

Poly(tetrafluoroethylene-co-perfluoropropyl vinyl ether) (PFA) with 2 mol% perfluoropropyl vinyl ether (PPVE) was exposed to gamma -irradiation in vac uum at both 77 K and room temperature and the ESR spectra recorded. Both th e main chain, similar to CF2-(CF)-F-.-CF(2)similar to, and end chain, simil ar to (CF2CF2)-F-. radicals were identified at both temperatures and their thermal stabilities measured, No radicals unique to the radiolytic cleavage at the PPVE units were observed at room temperature, either due to the low concentration of the comonomer or beta -scission to form a chain end radic al and a nonradical species. G-values for radical formation at room tempera ture and 77 K were found to be 0.93 and 0.16, respectively. (C) 2001 Elsevi er Science Ltd. All rights reserved.