The smoke produced from the oxidative pyrolysis of perfluoro polymers: an ESR spin-trapping study

Spin adducts are observed when the unfiltered smoke produced during the aerobic pyrolysis of perfluoro polymers (PFP) is bubbled through a solution of the ESR spin trap alpha-phenyl-N-tert-butylnitrone (PBN). The spin adducts include those from an oxy radical and the fluorine atom, and in addition the spin trap is oxidized to PBNOx. The spin adduct of a chlorine atom also is observed, presumably because of chlorine-containing impurities in the polymers. Tetrafluoroethylene is produced during the pyrolysis of PFP; therefore, we subjected tetrafluoroethylene to the same pyrolysis as was used for PFP, and we observe the same series of spin adducts. We suggest that the spin adducts formed from the whole, unfiltered smoke from PFP smoke may result both from free radicals that form during the pyrolysis of PFP and from the oligomerization of the tetrafluoroethylene produced during the pyrolysis. These spin-trapping results support the theory that reactive free radicals are present in PFP smoke and may contribute to PFP smoke toxicity.