A. I. Bol’shakov

Initiation of free-radical polymerization of acetylene monomers with molecular chlorine at low temperatures

The reactions of molecular chlorine with phenylacetylene (PA) and para-diethinylbenzene (p-DEB) at low temperatures (77–210 K) were studied by electronic paramagnetic resonance (EPR), size exclusion chromatography, double bond analysis (DBA), calorimetry, and UV, visible, and IR spectroscopy. The low-temperature (100–210 K) reactions of molecular chlorine without high-energy chemical (HEC) effects formed radicals capable of oligomerizations and polymerizations. A readily soluble polymer para-diethinylbenzene having no spatial cross-linkages (but possibly having a branched structure) was obtained. Polymerization occurred in direct contact with chlorine. It accelerated near the melting point (Tm) of chlorine and proceeded vigorously along with chlorination at Tm = 172 K. The occurrence of low-temperature polymerization without HEC treatment points to the high reactivity of the reagents. From the viewpoint of applications, low-temperature oligomerization or polymerization of monomers with molecular chlorine can afford oligomers or polymers with definite properties, which cannot be obtained by other initiation procedures.

A spectrophotometric, electron spin resonance, and calorimetric study of low-temperature postradiation living radical polymerization of vinyl monomers in the presence of C60 fullerene

By means of UV-visible spectrophotometry, ESR spectroscopy, and calorimetry, it was shown that the low-temperature postradiation polymerization of vinyl monomers in the presence of C60 fullerene (the yield of fullerene linking was above 90%) occurred via the radical mechanism in the living mode over the temperature range of 120–140 K.

Low-temperature polymerization of acrylamide under the action of molecular chlorine

Acrylamide can polymerize under the action of molecular chlorine in the temperature range 180–210 K, as evidenced by the methods of calorimetry; UV, IR, and EPR spectroscopy; and elemental analysis.

Spontaneous polymerization of acrylamide in glycerol

The spontaneous polymerization of acrylamide in glycerol in the range of 250–350°C has been first observed and investigated. It has been shown that the polymerization proceeds during dissolution of acrylamide in glycerol and leads to formation of gel globules in which the growth of polymer chains takes place. The reaction occurs without termination of kinetic chains in the living polymerization mode. The effective chain transfer at a low concentration of active centers ensures a high yield of the polymer.

Low-temperature radical polymerization of acrylamide in ethanol and glycerol under the action of molecular chlorine

It is shown by means of calorimetry, IR and EPR spectroscopy, elemental analysis, chromatography, and viscosimetry that radicals formed during the low-temperature action of molecular chlorine on acrylamide or its solutions in ethanol or glycerol initiate the polymerization reaction of acrylamide. It is established that during the low-temperature chlorination of pure acrylamide, polymerization takes place in the temperature range of 180–210 K with a polymer yield of ∼10%. The low-temperature chlorination of 20% solutions of acrylamide in ethanol or glycerol was performed to increase the product yield. It is shown that the low-temperature chlorination of acrylamide solution in glycerol increases the polymer yield by a factor of approximately two, and the content of chlorine in it falls by a factor of around ten. The low-temperature chlorination of acrylamide solution in ethanol did not lead to an increase in the polymer yield. A small reduction was noted in the chlorine content of the polymer.

Radiation telomerization of tetrafluoroethylene in chlorinated telogens at a constant reactor pressure

The kinetics of the radiation-initiated telomerization of tetrafluoroethylene (TFE) in the solutions of telogens (butyl chloride, chloroform, methylene chloride, and carbon tetrachloride) at a constant monomer pressure in the reactor was studied. In the course of the Γ-irradiation of the reaction mixture, TFE telomers containing repeatedly soluble and insoluble fractions were formed. In chloroform, methylene chloride, and carbon tetrachloride, the rapidly occurring process of the synthesis of insoluble telomer made the main contribution to the total yield of products. For the solutions of TFE in butyl chloride, the rates of formation of soluble and insoluble telomers were almost the same. The average chain length and the thermal stability of the resulting telomers were evaluated.

Methyl acrylate and methyl methacrylate oligomerization initiated by radicals generated via low-temperature treatment with molecular chlorine

By means of liquid chromatography, UV spectroscopy, calorimetry, and elemental analysis, it has been shown that the radicals generated spontaneously during low-temperature (77 K) mixing of the methyl acrylate (MA) and methyl methacrylate (MMA) monomers with molecular chlorine initiate the MA and/or MMA oligomerization reaction. The oligomerization and chlorination reactions occur as the mixtures prepared at 77 K are heated, having the reaction onset temperature below the chlorine melting point (170 K) and a maximal rate in the MA premelting region (180–190 K) for the MA-Cl2 mixture or the MMA melting range (220–230 K) for the MMA-Cl2 mixture.

Spontaneous polymerization of acrylamide in glycerol: Active centers and specific features

The nature of active centers and the specific features of the spontaneous polymerization of acrylamide in glycerol in the range 300-77 K have been studied. Glycerol activation is needed for polymerization. At this stage, active intermediate species are formed and stabilized under the action of photo-and γ radiation. Intermediate species are hydroperoxide compounds resulting from the sensitized (through technical traces) photolysis (or radiolysis) of glycerol. The decomposition of hydroperoxides into radicals on addition of finely dispersed acrylamide powder into the activated glycerol yields primary acrylamide radicals that initiate the growth of polymer chains.

Radiation-chemical synthesis of tetrafluoroethylene telomeres in butyl chloride and their use for imparting superhydrophobic properties to a polyester fabric

Tetrafluoroethylene (TFE) telomeres were synthesized in a butyl chloride solution using the radiation-chemical initiation of the reaction. The surface of a polyester material was modified with TFE telomeres to impart superhydrophobic properties to the fabric.

Radiation-initiated telomerization of tetrafluoroethylene in acetone at a constant monomer concentration

Kinetics of radiation-initiated polymerization of tetrafluoroethylene in acetone was studied at various initial concentrations (pressures) of the monomer in the reactor, which remain constant in the course of synthesis. Concentrated solutions of tetrafluoroethylene telomers were obtained and their properties were examined.