Thermal degradation of perfluoropolyphenylenes

Abstract

SynopsisThe thermal degradation of metu-and para-linked perfluoropolyphenylenes in uacuo and in oxygen has been studied. Rates of breakdown were determined thermogravimetrically and products of breakdown in vacuum analyzed by using a mass spectrometer. The thermal stability in YUCUO was comparable with that of polyphenylene, and that in oxygen was rather inferior to that of polytetrafluoroethylene. The higher molecular weight polymers gave as the main volatile degradation products silicon tetrafluoride and carbon dioxide, together with a carbonized residue containing virtually no fluorine.

Critical Review of Thermal Decomposition of Per- and Polyfluoroalkyl Substances: Mechanisms and Implications for Thermal Treatment Processes

“…74 Fully fluorinated polymers made up of tetrafluoroethylene and/ or hexafluoropropylene are the most thermally stable. 71,74 Also, increasing molecular weight tends to reduce thermal stability, 29,30 and some copolymers containing trifluoronitrosomethane (CF 3 NO) or (OCF 2 ) monomers are poorly stable, decomposing at temperatures as low as 200 °C. 71,72 Reactor materials and reaction conditions (e.g., presence of O 2 ) also influence the thermal stability of PFASs.…”

“…The temperatures required to decompose fluoropolymers are related to monomeric structure, extent of fluorination, and physiochemical conditions (e.g., reactor material, atmosphere). − Baker and Kasprzak found that −CF 3 branching leads to reduced Teflon thermal stability . Overall, polymers of perfluoroethylene are more stable than perfluorophenylene . Fully fluorinated polymers made up of tetrafluoroethylene and/or hexafluoropropylene are the most thermally stable. , Also, increasing molecular weight tends to reduce thermal stability, , and some copolymers containing trifluoronitrosomethane (CF 3 NO) or (OCF 2 ) monomers are poorly stable, decomposing at temperatures as low as 200 °C. , …”

“…Overall, polymers of perfluoroethylene are more stable than perfluorophenylene . Fully fluorinated polymers made up of tetrafluoroethylene and/or hexafluoropropylene are the most thermally stable. , Also, increasing molecular weight tends to reduce thermal stability, , and some copolymers containing trifluoronitrosomethane (CF 3 NO) or (OCF 2 ) monomers are poorly stable, decomposing at temperatures as low as 200 °C. , …”

“…The thermal decomposition products of fluoropolymers include monomers, dimers, trimers, perfluorocarbons, CO 2 , and SiF 4 (when quartz is present). , C 2 F 4 was the primary pyrolysis product of polytetrafluoroethylene (PTFE) . The subsequent decomposition of C 2 F 4 is discussed in Section .…”

Mechanistic exploration of polytetrafluoroethylene thermal plasma gasification through multiscale simulation coupled with experimental validation

“…These byproducts can contribute to the greenhouse effect 22 and exert harmful effects on the skin, eyes, respiratory system, lung and skeleton [23][24][25] . Moreover, available studies fall short in quantitatively accounting for all the fluorine in the thermal treatment system, achieving a complete fluorine mass balance as well as confirming the degradation mechanism of PTFE 9,26 . The current state of research makes the researchers question the effectiveness of PTFE mineralization via thermochemical conversion technologies and the associated risks of fluorochemical byproducts.…”