P. P. Kushch

Radiation-chemical synthesis and properties of tetrafluoroethylene telomeres in fluorine-containing solvents

The kinetics of radiation telomerization of tetrafluoroethylene in a series of fluorine-containing solvents was studied. A comparative analysis of their reactivity was carried out. The structure and some properties of the telomeres were studied by IR spectroscopy, thermogravimetric and elemental analysis, and electron microscopy.

The Specifics of Radiation Telomerization of Tetrafluoroethylene in Chlorinated Solvents and Telomer Properties

Radiation telomerization of tetrafluoroethylene in butyl chloride, chloroform, and carbon tetrachloride has been investigated. The chain length of telomers and their solubility and thermal stability depend on the initial monomer concentration and telogen properties. In the case of telomerization in chloroform and carbon tetrachloride, the yield, the chain length, and the thermal stability of the telomers are significantly higher than those in butyl chloride, in which the process is less efficient but soluble telomers having a short chain length and exhibiting quite high thermal resistance are produced. The molecular structure of the telomers has been studied by IR spectroscopy.

Low-temperature radiation telomerization of tetrafluoroethylene in hexafluoroisopropanol

The kinetics of low-temperature (180–270 K) postradiation telomerization of tetrafluoroethylene in hexafluoroisopropanol has been investigated. The efficiency of the process is determined by the initial concentration of the monomer in the solvent and the dose of preliminary irradiation. It has been shown that the telomerization reaction proceeds via the radical mechanism during the devitrification of the system. Active centers that initiate the process and their yield at 77 K have been studied by the ESR technique. Some properties of the product telomers have been studied.

Use of solutions of radiation-synthesized telomers of tetrafluoroethylene to modify glass fiber

In this work, we have suggested a new approach to fabricating fluorine-containing glass fibers based on the infiltration of glass-fiber filler by radiation-synthesized telomer solutions of tetrafluoroethylene. The radiation-chemical synthesis of tetrafluoroethylene telomers has been carried out in some solvents, their thermal stability has been studied, and the effectiveness of various telomers has been evaluated.

Low-temperature post-irradiation telomerization of tetrafluoroethylene in alcohols

Kinetic calorimetry was used to study the kinetics of low-temperature post-radiation telomerization of tetrafluoroethylene in ethanol and hexafluoroisopropanol. The temperature range in which the reaction occurs and its efficiency depend on the phase state of the reaction mixture at low-temperatures and on the chemical nature of the solvent. The nature of active centers initiating the telomerization process of tetrafluoroethylene in hexafluoroisopropanol and their accumulation kinetics were examined by EPR spectroscopy. The molecular structure and properties of the resulting telomers were examined by IR spectroscopy and thermogravimetric analysis.

Radiation-chemical synthesis of tetrafluoroethylene telomers in chloropentafluorobenzene and perfluoroxylene

The kinetics of radiation-induced telomerization of tetrafluoroethylene in chloropentafluorobenzene and perfluoroxylene have been studied. Colloidal solutions of thermally stable tetrafluoroethylene telomers with a chain length of 50–160 units have been obtained. A comparative analysis of the reactivity of some monohalogenated benzene derivatives used as telogens has been performed.

An NMR, DSC, and IR spectroscopy study of the composite formed during low-temperature postradiation polymerization of C2F4 in the presence of a 3D graphene material

By solid-state magic angle-spinning nuclear magnetic resonance spectroscopy (NMR), differential scanning calorimetry (DSC), and IR spectroscopy, polytetrafluoroethylene (PTFE) samples obtained by low-temperature (T = −196°C) postradiation polymerization of tetrafluoroethylene (C2F4) and C2F4 mixtures with a 3D graphene material formed by the microwave exfoliation of graphite oxide films (MEGO) have been investigated. It has been shown that the melting point of PTFE in the PTFE-MEGO composite is 332.5°C, which is 8.8°C above the melting point of pure PTFE obtained under the same conditions. According to the measured values of specific enthalpy of melting ΔHm (51.5 and 45.4 J/g), the degrees crystallinity (xc) of 0.63 and 0.55 have been calculated for the pure polymer and the composite, respectively. It has been also found that none of the PTFE-containing samples examined has terminal CF3 groups typical of PTFE prepared by conventional suspension polymerization.

Mechanism of the initiation of low-temperature radiation telomerization of tetrafluoroethylene in hexafluoroisopropanol

ESR and IR spectroscopy and scanning calorimetry are used to investigate the mechanism of low-temperature radiation telomerization of tetrafluoroethylene (TFE) in hexafluoroisopropanol (HFIP). It is found that the low-temperature telomerization of TFE in HFIP proceeds via an ion-radical mechanism. This process is initiated by the radical anions (CF3)2C·-O− formed during the deprotonation of OH groups of primary hydroxyl radicals (CF3)2C·-OH exhibiting strong acidic properties. An interpretation of ESR spectra of irradiated HFIP recorded at 230–240 K is proposed with regard to the anisotropy on β-fluorine atoms and estimates of the angles between the corresponding C-F bonds and the axis of the unpaired electron orbital.

Multifunctional Compound Combining Conductivity and Single-Molecule Magnetism in the Same Temperature Range

We report the first highly conducting single-molecule magnet, (BEDO)4[ReF6]·6H2O [1; BEDO = bis(ethylenedioxo)tetrathiafulvalene], whose conductivity and single-molecule magnetism coexist in the same temperature range. The compound was synthesized by BEDO electrocrystallization in the presence of (Ph4P)2[ReF6]·2H2O and characterized by crystallography and measurements of the conductivity and alternating-current magnetic susceptibility.

Preparation and properties of composites based on caramelized aluminoborosilicate fabric and tetrafluoroethylene telomers

New composites based on activated caramelized aluminoborosilicate glass fabric and radiationsynthesized tetrafluoroethylene telomer solutions were prepared, and their properties were studied. The properties of materials prepared from standard commercial and caramelized glass fabrics were compared.