Tetrafluoroethylene Copolymers with Sulfonyl Fluoride Pendants: Syntheses in Supercritical Carbon Dioxide, Polymerization Behaviors, and Properties

Abstract

Copolymerizations of tetrafluoroethylene (TFE) and perfluoro(3,6‐dioxa‐4‐methyl‐7‐octen)sulfonyl fluoride (PSVE) initiated by bis(perfluoro‐2‐n‐propoxypropionyl) peroxide in supercritical carbon dioxide are investigated. The reactivity ratios for TFE (rTFE) and PSVE (rPSVE) are calculated to be 7.85, 0.079 and 7.92, 0.087 according to Fineman–Ross and Kelen–Tudos methods, respectively. The glass transition temperatures of the copolymers increase with increasing in PSVE content. Comparison studies on above copolymers and another fluorinated sample prepared in emulsion show that the copolymers have comparable properties to the fluorinated one, thus offering an economic way to improve the properties of TFE–PSVE copolymers for their applications in diverse fields. magnified image

Copolymerizations of tetrafluoroethylene and perfluoropropylvinyl ether in supercritical carbon dioxide: Polymer synthesis, characterization, and thermal properties

“…It is understandable that both perfluorinated main chains and perfluoroalky end groups endowed resultant copolymers with good stability under higher temperatures. To inspect the early thermogravimetry process where weight loss would be related with polymer end groups,36 the temperatures for 1 wt % loss ( T 1 ) for these PFA copolymers are also obtained. The results show that all T 1 values are higher than 415°C, similar to normal commercial Hyflon ® PFA ( T 1 = 420–440°C) which has been dealt with fluorination.…”