Low-temperature fluorination of fluoro-containing polymers

Degradation of γ-irradiated linear perfluoroalkanes at high dosage

“…Such an approach has been shown to yield good relative bond energies at the MP2 level for hydrofluorocarbons [31,32]. The terminal C-F bond energies are always stronger than the interior C-F bond energies by about 10 kcal/mol consistent with the C-F bond energies in other fluorinated compounds.…”

“…[5], unsaturated products are not formed during radiolysis of PTFE in vacuum. The very low radiation-chemical yield of unsaturated products is only observed during irradiation of PTFE in air [7] when oxygen is present which leads the presence of oxygenated radicals [32]. These data show that the cation-radical mechanism cannot explain the radiation destruction of PTFE.…”

Morphology of polyvinylidenefluoride and the copolymer of tetrafluoroethylene with ethylene using thermomechanical analysis

“…2. The reaction of CTE or PVDF with fluorine at low temperatures results in the abstraction of hydrogen leading to the formation of radicals which were detected at 35 K. The radical concentration produced by fluorination of CTE at 77-200 K is 10 times greater than that of the PVDF radicals formed under similar conditions due to differences in the CÀ ÀH bond energies.…”

“…The reaction of CTE or PVDF with fluorine at low temperatures results in the abstraction of hydrogen leading to the formation of radicals which were detected at 35 K. The radical concentration produced by fluorination of CTE at 77-200 K is 10 times greater than that of the PVDF radicals formed under similar conditions due to differences in the CÀ ÀH bond energies. 2 In addition, PVDF has only slightly more fluorine after fluorination with the difference below the accuracy of the energy dispersion microscopy method (1%). However, we note that radical centers are formed which suggests that some fluorine has been added.…”

“…In contrast, the fluorine content in CTE increases by $ 3% on direct fluorination. 2 The PVDF and CTE polymers differ in how the À ÀCH 2 À À and À ÀCF 2 À À groups alternate. In PVDF, the À ÀCH 2 À À and À ÀCF 2 À À groups alternate so that every À ÀCH 2 À À is between two À ÀCF 2 À À groups, whereas in CTE, two À ÀCH 2 À À groups are found between the two À ÀCF 2 À À groups.…”