Plasma Copolymerization of Tetrafluoroethylene and Chlorotrifluoroethylene

Abstract

Considerable interest has been shown in the plasma polymerization of tetrafluoroethylene¹ (TFE) and some attention has been given to the plasma polymerization of chlorotrifluoroethylene^2–9 (CTFE). However, the plasma copolymerization of these two monomers has apparently not been reported previously, although their conventional copolymerization has been described.¹⁰ As a follow-up to our prior work on the plasma copolymerization of ethylene (ET) and TFE,¹¹ we examined the TFE-CTFE plasma copolymerization with the aim of preparing chlorine-containing, plasma-polymerized’l’FE (PPTFE) that might be more readily derivatized than the customary PPTFE itself. The rationale was that CI atoms incorporated into PPTFE-like structures might be more amenable to post-plasma chemical substitutions than F atoms (e.g., by reaction with NH3), given the fact that C-Cl bonds are weaker than the corresponding C-F bonds by ≈ 25−30 kcal/mol. Apparently only three other plasma copolymerization studies have been reported involving CTFE as one of the monomers: copolymerization with benzene⁶ and copolymerization with trifluoromethanesulfonic acid^9,12 or perfluoroallylphosphonic acid.⁹