NMR Study of the Radiation-Induced Cross-Linking of Poly(tetrafluoroethylene-co-perfluoromethyl vinyl ether)

The γ-radiolysis of poly(tetrafluoroethylene- co -perfuoromethyl vinyl ether) (TFE/PMVE) was investigated using solid state 19 F and 13 C NMR spectroscopy. Chain scission products identified in the polymer were saturated chain ends −CF 2 CF 3 ( G = 1.0), methyl ether end groups −CF 2 OCF 3 ( G = 0.9), acid end groups −CF 2 COOH ( G = 0.5), and a small amount of terminal unsaturation −CF CF 2 ( G = 0.2). A mechanism for the formation of these scission products was proposed and the G value for main chain scission, G (S), was determined to be 1.4. Cross-linking of TFE/PMVE was found to proceed via a Y -linking mechanism. The G value for cross-linking, G (X), was determined to be 0.9. A maximum of 0.2 mol % cross-links were formed under the experimental conditions.