I. A. Ionova

Fullerene C60 in copolymerization of allyl chloride with methyl methacrylate

The effect of fullerence C60 on the copolymerization of allyl chloride and methyl methacrylate has been studied. With the use of UV spectroscopy, it has been shown that, with an increase in the conversion, the redistribution of optical densities of two π-π* absorption maxima due to fullerene at λmax = 407 and 330 nm is observed. A difference in the kinetics of copolymer’s formation in the absence and presence of fullerene has been found.

Free-radical polymerization of methyl methacrylate in the presence of a ferrocenyl-containing iron(II) clathrochelate complex and initiators of various natures

Benzoyl peroxide-, lauryl peroxide-, and AIBN-initiated free-radical polymerization of methyl methacrylate has been studied in bulk and solution in the presence of macrobicyclic iron(II) bis(ferrocenyl borate) tris(nioximate). It has been found that the ferrocenyl-containing iron(II) clathrochelate forms efficient initiating systems with peroxides, whereas, in the case of AIBN, its presence has no effect on the kinetic parameters of the process and the properties of the resulting polymer. The use of clathrochelate complex-peroxide initiator systems accelerates the polymerization of methyl methacrylate and decreases the molecular mass of the polymer. The kinetic parameters of the process have been determined.

Effect of the concentration, distribution and degree of neutralization of the carboxyl groups, and of the nature of the cation, on the thermomechanical properties of ionomers☆

A study has been made of the effect of the concentration of carboxyl groups and their distribution along the copolymer chain on the thermomechanical and physicomechanical properties of ionomers. It is shown that when there is a random distribution and a low concentration of carboxyl groups in the polymer the degree of neutralization and the nature of the cation has little effect on the transition temperatures of ionomers. When the concentration of carboxyl groups is high the thermomechanical characteristics of neutralized samples are dependent on the concentration and nature of the cation.

Polymerization of butadiene with a halogen-containing trans-regulating neodymium-magnesium catalytic system in the presence of carbon tetrachloride

The polymerization of butadiene in toluene initiated by the NdCl3 · 3TBP-Mg(C4H9)(i-C8H17) (TBP is tributyl phosphate) catalytic system has been studied. It has been shown that the polymerization reaction under study is a nonstationary slowly initiated process. The addition of carbon tetrachloride promotes an increase in the catalytic activity of the system. The products of polymerization have low molecular masses and polydispersity indexes. The content of 1,4-trans-units in the polymer is as high as 95%.

Composition of fullerene-containing styrene-diallyl isophthalate copolymers

The effect of fullerene C60 on the composition of macromolecules in the free-radical copolymerization of styrene with diallyl isophthalate is estimated. It is shown that the maximum amount of C60 is contained in the high-molecular-mass fraction of the products. Constants in the Kuhn-Mark-Houwink equation are determined for the fullerene-containing copolymer synthesized from an equimolar mixture of monomers.

Kinetic inhomogeneity of copolymerization sites of butadiene and isoprene on titanium catalyst

Copolymerization of butadiene and isoprene on the titanium catalyst proceeds on three types of active sites, and this correspond to the standard set of homopolymerization of isoprene. Sites responsible for the preparation of low-molecular-mass fractions of macromolecules are more active in the copolymerization as compared with homopolymerization of butadiene and isoprene. Change in the hydrodynamic regime in the reaction region is accompanied by an increase in the copolymerization rate due to an increase in the over-all concentration of active sites but it does not affect the typical set of growth sites of macromolecules. Distribution curve of active sites with respect to their reactivity is shifted to the high-molecular-mass region with increasing average weight molecular mass with decreasing average number molecular mass when the corresponding molecular-mass distribution becomes broader.

New opportunities in synthesis of fullerene-containing polymers of allyl series

Corrosion resistance of tantalum, titanium, and a number of carbon materials in a NaOH melt in the atmosphere of argon was studied in the temperature range 400–700°C.

Kinetic nonuniformity of a titanium catalyst in the polymerization of butadiene: Effect of intensifying stirring of the reaction mixture

Intensification of turbulent stirring of the reaction mixture in the course of butadiene polymerization on a titanium catalyst promotes a successive increase in the rate of reaction with increasing polymer content. Independent of the viscosity of the reaction mixture, the concentration of active centers forming the low-molecular-mass fraction of polybutadiene decreases and the molecular mass distribution narrows. The reactivity distribution of active centers is determined by the hydrodynamic effect, and it does not depend on the increasing viscosity of the reaction mixture. This suggests an insignificant influence of viscosity and, hence, diffusion limitations on the distribution of active centers of polymerization over the probability of chain propagation.

Disperse Composition of Titanium–Magnesium Catalyst Particles and trans-1,4-Polyisoprene Granules in Short-Time Polymerization

The disperse composition of trans-1,4-polyisoprene granules and supported titatium–magnesium catalyst particles in the ultrarapid polymerization of isoprene within 0.1–0.7 s is studied. It is shown that within this period the alteration of external and internal fragmentations occurs between two fractions of polymer granules that are formed by 0.1 s of polymerization and already contain significantly fragmented catalyst particles. The correlation between these processes and molecular mass characteristics of trans-1,4-polyisoprene is investigated. It is found that the external fragmentation is accompanied by a decrease in the average molecular masses of the polymer, while the internal fragmentation leads to formation of a higher molecular mass trans-1,4-polyisoprene. As a result, the fraction of polymer granules with a diameter of 7.5 μm is formed by 0.7 s of polymerization and replication to high conversions is developed on their basis.

Kinetic features of short-time polymerization of isoprene in the presence of supported titanium–magnesium catalyst

Short-time polymerization of isoprene under the action of supported titanium–magnesium catalyst is carried out. The pulsation mixing of the reagent flows and the unit design features allow one to reduce the average residence time of reagents in the reaction zone and to study the first 0.7 s of the isoprene polymerization. It is found that, very early in polymerization, the propagation of polyisoprene macromolecules proceeds on the surface of the primary aggregates of catalyst particles characteristic of a high trans-1,4 specificity via the “living” mechanism with a high rate. Furthermore, the fragmentation of the initial aggregates of the catalyst particles occurs, which results in formation of new polymerization centers, a decrease in the average molecular masses of polyisoprene, and a broadening of the polymer MMD. The results are explained by the existence of a range of the kinetic continuity of the rapid initiation stage and several subsequent stages of macromolecule propagation, followed by a significant decrease in the chain propagation rate constant compared to the initiation constant.