Synthesis and structural peculiarities of 1,1‐dimethylhydrazine‐based polyurethanes

Novel polyurethanes (PUs) based on poly(oxytetramethylene glycol), 4,4′‐methylenediphenyl diisocyanate, and 1,1‐dimethylhydrazine (DMH) were prepared. Stoichiometric (1 : 1) and nonstoichiometric (2 : 1 to 20 : 1) prepolymer/DMH ratios were studied. The number‐average molecular masses and possible structures of the obtained polymers were evaluated by potentiometric nonaqueous titration analysis of terminal groups, the Kieldal method (the evaluation of the nitrogen atom content), the aminolysis method, viscosimetry, IR spectroscopy, rheology, and small‐angle X‐ray scattering. Only in the case of the stoichiometric (1 : 1) ratio was a low‐molecular‐mass PU with a linear structure formed, whereas for all studied nonstoichiometric ratios, PUs with branched structures were formed. The level of hard and flexible block segregation increased with the increase in the prepolymer/DMH ratio. Dielectric results for the dynamic glass transition and water sorption measurements provided additional support to the structural studies. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Prospects of the development of electricity generation capacities in Russia

The results of studies of prospects of the development of the electricity-generation capacitiesí structure regarding types of power plants and kinds of fuel used at them are presented. These studies have been restarted by the initiative of state institutions and RAO Unified Energy Systems of Russia.     

Results of Comparative Durability Investigations of Cutting-Ceramic Indexable Inserts in the Turning of Hardened Steel Blanks

Glass and Ceramics - The results of a durability investigation of a cutting ceramic—a replaceable cutting insert [RCI], developed at NSTU, and VOK-60 cutting ceramic in machining of hardened...     

Low-temperature plasma pulsed deposition of thin films with nanoscale periodicity of properties

Semiconductors - Film formation in low-temperature plasma in the pulsed mode was studied. The voltage’s pulse sequence in the sputtering system contained trains of short and long pulses; the...