Spectroscopic Investigation of Sublimated Products of Ultradisperse Polytetrafluoroethylene

Quantum chemistry calculations of branched fluorocarbon systems

“…These factors could yield the changes in elasticity, mobility, regularity, and, therefore, crystallinity of the polymer. The latter is in agreement with the emergence of a band at 986 cm À1 in IR spectra of UPTFE (ultradispersed PTFE) revealed in [30], which is assigned to vibrations of the side trifluoromethyl group and increase of the degree of the sample amorphousness.…”

“…The fact that branches are formed on the account of formation of side trifluoromethyl groups in a chain was assumed in the works [2,29,30] on the basis of studies of IR spectra of PTFE samples that underwent radiation, thermal, and mechanical treatment. The calculations of energy properties of the process of bonding of the CF 3 radicals to C 4 F 9 ones using the DFT (B3LYP, 6-311+G(d)) method [13] demonstrated that bonding of the CF 3 radical to the formed (for example, upon irradiation) C 4 F 9 radical resulted in the system stabilization.…”

Post‐synthesis Carbon Nanowalls Transformation under Hydrogen, Oxygen, Nitrogen, Tetrafluoroethane and Sulfur Hexafluoride Plasma Treatments

“…The attribution of IR bands of CNWs treated in plasma with gas mixtures of the type Ar/SF 6 and Ar/C 2 H 2 F 4 is shown in Table 3 36–39, 41–46. For the post‐treatment of CNWs with the gas mixture Ar/C 2 H 2 F 4 we remark on curve e in Figure 3, in comparison with curve a in Figure 3, two new absorption bands peaked at ca.…”

Quantum chemistry studies of unbranched fluoropolymers

“…The hypothesis that branching takes place due to formation of side trifluoromethyl groups was repeatedly put forward [4,22,23,26] on the basis of studies of IR spectra of PTFE samples subjected to radiation, thermal and mechanical treatment. The calculations of energy parameters of the process of the CF 3 -group addition to C 4 F 9 radicals performed by the DFT (B3LYP, 6-311+G(d)) method:…”

“…On the contrary, in the IR spectra of PTFE irradiated samples [22] or ultradispersed modifications obtained by polymer pyrolysis [23,26] the above range is characterized by the presence of rather weak, albeit in most cases identifiable, band at 986 cm À1 . This band is usually attributed to the -CF 3 groups' vibrations.…”