Dilatometric method of investigating the phase transitions of elastomers in the deformed state

A method is proposed for investigating crystallization and melting processes in vulcanizates in relation to the change of volume of specimens in the compressed or extended state. The method combines the advantages of dilatometry (accuracy of quantitative estimates) and mechanical methods (possibility of acceleration of crystallization associated with orientation of the macromolecules). The vulcanizates are tested under realistic conditions. Vulcanizates of NT Nairit and cis-1,4-polybutadiene have been tested by means of the method described; the crystallization kinetics are shown to depend on the degree of extension and compression of the specimens.Lebedev All-Union Scientific-Research Institute of Synthetic Rubber, Leningrad. Translated from Mekhanika Polimerov, No. 5, pp. 780–784, September–October, 1970.     

Reduction of 1,2,3,4-tetrahydro-γ-carbolines with alkali metal borohydrides in trifluoroacetic acid

A preparative method for the synthesis of 9- (2,2,2-trifluoroethyl)-1,2,3,4,4a, 9a-hexahydro--carbolines by the action of alkali metal borohydrides in trifluoroacetic acid on 1,2,3,4-tetrahydro--carbolines was developed. The indicated trifluoroethyl derivatives can also be obtained by reaction of the same reagents with 1,2,3,4,4a,9a-hexahydro--carbolines, which are intermediates in the overall reduction-trifluoroethylation process.See [1] for a preliminary communication.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1383–1386, October, 1980.     

Eigenschaften von polymolekularen Wasserfilmen auf der Oberfläche von Quarzkapillaren

Ohne Zusammenfassung     

Effect of crystalline phase on the elasticity of rubbers

The dynamic mechanical properties of crystallizing divinyl and isoprene rubbers have been investigated over a wide temperature range. It is shown that the formation of a crystalline phase in the rubber leads to a regular increase in rebound resilience in the transition temperature range. The demonstrated relation between these quantities shows that the minimum elasticity can be used as a measure of the crystalline phase present in the polymer.Mekhanika Polimerov, Vol. 1, No. 3, pp. 15–20, 1965     

Synthesis of α-myrcenol acetate and propionate from isobutenylcarbinol

A synthesis of -myrcenol acetate and propionate was carried out by a controled combination of suitable isobutenylcarbinol derivatives according to the Wurtz reaction.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 591–594, March, 1990.     

Single-crystal structure of vanadium-doped La2Mo2O9

A high-precision X-ray diffraction study of single crystals of two compositions—La₂Mo_1.78V_0.22O_8.89 and La₂Mo_1.64V_0.36O_8.82—was performed. In the vanadium-doped compounds, as in the structure of the metastable β_ms phase of pure La₂Mo₂O₉, the La and Mo atoms and one of the three oxygen atoms are displaced from the threefold axis, on which they are located in the high-temperature β phase. The structure contains two partially occupied oxygen sites. It was shown that molybdenum atoms are partially replaced by vanadium atoms, which are not involved in the disordering, are located on the threefold axis, and are shifted toward one of the oxygen atoms. This is consistent with the temperature-induced changes in the structure of La₂Mo₂O₉ and the changes in the properties of these crystals caused by the introduction of vanadium atoms into the structure.