Ionic species produced by mechanical fracture of solid polymer. III. Anions from polytetrafluoroethylene

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Abstract
The tetracyanoethylene anion radical (\documentclass{article}\pagestyle{empty}\begin{document}${\rm TCNE}^{ \cdot ^ - } $\end{document} ) was detected by ESR spectroscopy in polytetrafluoroethylene (PTFE), which had been mechanically fractured in vacuo with tetracyanoethylene (TCNE) at 77 K. The assignment of \documentclass{article}\pagestyle{empty}\begin{document}${\rm TCNE}^{ \cdot ^ - } $\end{document} was carried out by ESR spectral simulation on the basis of an anisotropic effective hyperfine tensor that included a forbidden transition term. The \documentclass{article}\pagestyle{empty}\begin{document}${\rm TCNE}^{ \cdot ^ - } $\end{document} is formed by abstraction of an electron by TCNE from the anion that is produced by heterogeneous scission of the carbon‐carbon bond in the main chain of PTFE. At least 16% of the scission of the main chains of PTFE occurs by a heterogeneous process to produce the anions. Approximately 50% of the anions decay during annealing for 30 min at 220 K in the dark, and all anions decay within 15 min at 325 K.