The calorimetric investigation of phosphoric acid-N,N-dimethylformamide system

Solution and mixing enthalpies for the orthophosphoric acid (H₃PO₄)-N,N-dimethylformamide (DMF) system were measured over the whole concentration range at 25 °C. The standard value of solution enthalpy of phosphoric acid in DMF and the standard transference enthalpy of H₃PO₄ from water to DMF were calculated. The mixing enthalpy concentration dependence permitted making assumptions on complex formation in the system under investigation.     

Luminescent properties of PP and LDPE films and rods doped with the Eu(III)‐La(III) complex

The work is devoted to luminescent properties of trivalent lanthanide complexes dispersed in thermoplastic host matrices. Polyethylene films and polypropylene‐rods, both doped with these complexes, were manufactured using an extrusion technique. Two kinds of dopants were used: Eu(III)‐thenoyltrifluoroacetone‐1,10‐phenanthroline complex (1) and Eu(III)‐La(III)‐1,10‐phenanthroline complex (2). Absorption, excitation, emission spectra and lifetime of luminescence were studied. The impact of the polymer matrix on the emission spectra was investigated. Emission spectra of the films were studied at room and helium temperatures. Time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS) surface mapping showed that in the Eu(III)‐La(III) complex europium forms islands (clusters) with a dimension of 1 µm, whereas lanthanum was dispersed more uniformly in the polymer matrix. Dependence of emission intensity on the excitation was determined. Copyright © 2006 John Wiley & Sons, Ltd.     

Calculation of properties of ternary liquid mixtures on the basis of properties of binary solutions

Various methods of calculating properties of ternary systems using the properties of binary solutions have been analyzed on the basis of experimental and published data.     

Change in the volume of orthophosphoric acid solutions in the neutralization with solutions of various bases

Volume changes in the reactions of orthophosphoric acid neutralization with solutions of NaOH, NH₄OH, and tris(hydroxymethyl)methanamine in the mixed solvent H₂O-dimethylformamide were studied by dilatometric titration. Volume effects of the reaction depending on the mixed solvent composition and base strength were discussed.     

Proton-conducting gel electrolytes based on poly(methyl methacrylate) doped with phosphoric acid in <Emphasis Type="Italic">N,N</Emphasis>-dimethylformamide

Time-stable proton-conducting gel electrolytes based on poly(methyl methacrylate) doped by o-phosphoric acid solutions of different concentrations in DMF are prepared. The dependences of the electrical conductivity of the gels on the concentrations of the acid and polymer and the molecular mass of PMMA at 25–65°C are studied. The thermal stability of electrolytes is estimated. It is found that an increase in the content of the polymer in gels changes the thermal behavior of the samples.     

Conductivity and thermal stability of proton-conducting electrolytes at confined geometry of polymeric gel

The proton-conducting gel electrolytes based on poly(methyl methacrylate) (PMMA) doped by acid solutions in aprotic solvents were synthesized and discussed in this work. The gel conductivity as a function on concentrations of acid and polymer as well as of molecular mass of PMMA has been analyzed. The thermal stability of electrolytes was estimated and discussed. Extreme dependence of the conductivity on concentration is found to be for the gel (at a concentration of PMMA from 5 to 15 wt.%). The increase of electrical conductivity in the concentration range from 5 to 10 wt.% of PMMA with an increase in viscosity of the system is discussed as an indication of an involvement of the polymer matrix in increasing the mobility of the charge carriers in frame of Grotthuss mechanism.     

Rotational and translational diffusion of low molecular weight substances in polyblock copolymers with soft and rigid blocks

The rotational diffusion of spin-probes and the translational diffusion of n-pentane in a series of random-block copolymers (BSP) have been studied as a function of composition and block lengths. It was shown that the local diffusion properties of the BCP microphases depend on these two characteristics of BCP. © 1995 John Wiley & Sons, Inc.     

Intermolecular interactions in orthophosphoric acid-<Emphasis Type="Italic">N,N</Emphasis>-dimethylformamide system according to viscometric data

The viscosity of an orthophosphoric acid—N,N-dimethylformamide system was measured in the whole region of compositions at 298–338 K. An excess viscosity of the system was analyzed by the data obtained using different model concepts. Calculations suggested that strong intermolecular interactions and the formation of complexes (H₃PO₄)₂·DMF occur in the system. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2252–2256, October, 2005.