A.G. Sakhabutdinov’s research while affiliated with Joint Stock Company National Research Institute Electron and other places

The influence of supported titanium-magnesium catalysts with various internal and external donors on the propylene polymerization in the liquid monomer medium and the characteristics of the polypropylene formed were studied. The following internal donors were used: dibutyl phthalate, diisobutyl phthalate, 9,9′-bis(methoxymethyl) fluorene, and diethyl 2,3-diisopropylsuccinate. The catalysts studied allow synthesis of polypropylene with high isotacticity (>96%) and different molecular-mass distribution (Mw/Mn from 3.3 to 6.3). The influence of external donors (alicyclic, amine) in combination with phthalate and nonphthalate electron-donor compounds on the stereospecificity and activity of the catalysts and on their sensitivity to hydrogen was studied. The optimum catalytic systems for preparing polypropylene for various purposes can be found by varying pairs of internal and external donors.

The effect of polymerization conditions (temperature, polymerization time, monomer and hydrogen concentrations) on propylene polymerization in the liquid monomer in the presence of a TiCl4/DBP/MgCl2 + TEA/cyclohexylmethyldimethoxysilane catalyst system is studied . It is shown that the variation of the propylene polymerization conditions in the studied ranges leads to a change in the characteristics of the resulting polypropylene. The kinetic parameters of propylene polymerization in the liquid monomer for the studied catalyst system are determined. Polymerization conditions providing the formation of polypropylene with high polymer yield, isotacticity, and bulk density values are found. The process parameters that make it possible to effectively control the molecular and rheological characteristics of polypropylene are identified.

The influence of the concentration of an initiating system consisting of n-butyllithium and an amine-containing modifier on the copolymerisation of 1,3-butadiene and styrene in a hexane solvent was studied. The molecular characteristics and the microstructure of specimens of the obtained solution-polymerised styrene butadiene rubber (s-SBR) were determined by gel permeation chromatography on a Breeze liquid chromatograph (Waters) and by IR spectroscopy on a Spectrum GX 100 spectrometer (PerkinElmer) in accordance with ISO 21561/2. It was shown that a reduction in the amount of the initiating system is accompanied with a reduction in the copolymerisation rate and in the monomer conversion, and also with an increase in the average molecular weights of the copolymer. It was established that a reduction in the initiating system concentration in the reaction medium leads to a reduction in the content of 1,2-units in the rubber. A comparative analysis of data for rubber compounds based on the synthesised s-SBR and data for rubber compounds based on standard rubber indicates that their mechanical properties are at the same level. However, the tg δ at 60°C (determined on an RPA 2000 instrument) for rubber compounds based on a trial specimen has a lower value, which will make it possible to produce tyre rubbers providing a lower tyre rolling resistance.

The relationships governing 1,3-butadiene copolymerisation in a hexane solvent in the temperature range 30-70°C were studied. The copolymerisation process was initiated by n-butyllithium. A mixture of alkali metal and alkaline earth metal amine-containing alcoholates (AMD) was used as the modifier. The microstructure and macrostructure of the obtained p-SBR specimens were investigated. In p-SBR specimens obtained in the presence of AMD in the investigated temperature range, the distribution of styrene units in block was not found. The introduction of AMD leads to the disappearance of the induction period and to an increase in the copolymerisation rate, i.e. the reactivity of the system increases, and a reduction in temperature accelerates this process. It was shown that, with increase in the process temperature, there is a reduction in the average molecular weights of the copolymer. In the presence of AMD, lowering of the copolymerisation temperature leads to 'enrichment' of the butadiene part in 1,2-units (up to 66.3%).

The kinetic parameters of copolymerization of 1,3-butadiene and styrene in hexane under the action of a ternary initiating system consisting of n-butyllithium, amine-containing alkali and alkaline earth metal alcoholates, and 2,2'-ditetrahydrofurylpropane were studied. The molecular mass characteristics and microstructure of the synthesized copolymer samples were examined. Physicomechanical tests of specimens of butadiene–styrene rubber prepared from solution and of vulcanized specimens based on them were performed.

The effect of the particle size of an IK-8-21 domestic titanium-magnesium catalyst on the properties of polypropylene (PP) produced during the polymerization of propylene in a liquid monomer is studied. Catalysts with particle sizes of 20 to 64 μm are shown to have high activity and identical sensitivity to hydrogen and allow PP to be obtained with a narrow distribution of particles over size, high isotacticity, and close values of crystallinity, melting temperature, and physicomechanical properties. A slight decrease in the activity and bulk density of PP powder is observed when the average size of catalyst particles is increased from 20 to 43 μm. A more notable reduction in the activity and bulk density of PP powder is observed for catalyst with particle sizes of 62 to 64 μm. IK-8-21 catalyst is not inferior to its foreign analogues with respect to the properties of the resulting PP.

Specific features of the copolymerization of 1,3-butadiene and styrene in the presence of n-butyllithium and a mixture of amine-containing alkali and alkaline earth metal alcoholates in hexane were studied. The kinetic parameters of the process and the molecular characteristics of the copolymer were determined. The suggested initiating system allows preparation of butadiene–styrene rubber with high content of 1,2-units in solution.

The studies were focused on the influence of particle size of the Russian Ti-Mg catalyst IC-8-21 on the properties of polypropylene (PP) synthesized by polymerization of propylene in a liquid monomer medium. The catalysts with particles of 20 to 64 mm in size were shown to be highly active, identically sensitive to hydrogen and to provide synthesis of PP with a narrow particle size distribution, high isotacticity, close values of crystallinity, melting temperature and physicomechanical properties. A minor decrease in the activity and bulk density of PP powder was observed with an increase in the average size of catalyst particles from 20 to 43 mm. The activity and bulk density decreased more considerably over the catalyst with particles of 62–64 mm in size. The properties of polypropylene synthesized over IC-8-21 are not inferior to the properties provided by the known analogues.