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A synthetic route to frost-resistant siloxane rubbers is developed on the basis of the anionic block copolymerization of a mixture of cyclooctamethyltetrasiloxane, hexaethylcyclotrisiloxane, and 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane in the presence of KOH. The resulting rubbers were used to produce frost-resistant elastomers. According to the results of DSC studies, the glass-transition temperature of the frost-resistant rubber is –129 °C; no crystallization or melting processes of the samples are detected on the thermograms. The elastomer obtained based on the siloxane rubber retains its operational characteristics even at the temperature as low as –123 °C.

The purpose of the article is to describe monitoring studies on the radiation state of air in populated and working areas near the uranium processing enterprise in the Republic of Uzbekistan. Ac-cording to the analytical measurement, the exposure dose of gamma radiation is equivalent to the equilibrium volume activity of radon, specific activity of long-lived alpha-emitting nuclides in the zone of influence of the enterprise, the working area, premises for storing uranium materials and manufacturing dumps, tailings dams and areas of underground uranium leaching. It was shown that the measurement results do not exceed the regional background and regulatory levels of radioactive radiation by all indicators. The dependence of the volume activity of radon at production facilities on the density of the radon flux from the soil was studied. The most intensive radioactive objects – uranium dumps – were identified. It was found out that there is no excess radioactive impact of the uranium enterprise on the environmental objects.

The exposure dose rates, the equivalent equilibrium volume activity of radon, and the activity of long-lived alpha-nuclides in the air of the uranium protoxide-oxide calcination shop were determined. Annual effective doses for workers were calculated. Through the use of nuclear-based polietilentereftalata and chemical filters, the disperse composition of particles in the air was studied. The effectiveness of filters in sampling was evaluated for the uranium content. The kinetics of distribution of uranium in various fractions was studied. The quality coefficients of filters that accumulate uranium relative to its norm in various working places of the shop were estimated.

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