Chemical, physical, and toxicological characterization of fumes produced by heating tetrafluoroethene homopolymer and its copolymers with hexafluoropropene and perfluoro(propyl vinyl ether).

Submicrometer solid-particle (fume) aerosols with up to about 10(8) particles/cm3 are formed when dilute vapors of low molecular weight (MW) (ca. 5000-10,000) perfluoro polymers condense in air. The aerosol (e.g., 0.2 mg/m3) formed from these vapors is highly toxic to laboratory rats by inhalation (30-min exposure) when fresh but loses toxicity in minutes, apparently owing to coagulation. These fumes may result from (a) pyrolysis of tetrafluoroethene homopolymer or tetrafluoroethene-hexafluoropropene copolymer or (b) evaporation, at 200-320 degrees C, of isolated low MW polymer or low MW polymer present in perfluoro polymer resins. Some perfluoro polymer fume aerosols contain reactive functional groups, but others without detectable reactive groups are at least as toxic.