Laser photoionization spectroscopy of rare-earth elements: New results on nuclear electromagnetic moments and charge radii of Eu,Gd and Tb isotopes

New results on spins, electromagnetic moments and isotopic changes of nuclear charge radii for ₆₃ ^157–159 Eu, ₆₄ ^{146, 148, 150} Cd and ₆₅ ^{147–155, 157, 159} Tb have been obtained from hyperfine structure and isotope shifte measured with laser resonance photoionization technique. These results complement two-dimensional picture (with respect to H and Z) of the changes of nuclear ground state properties near the “critical” neutron numbers N=88–90 in the vicinity of the “magric” proten number Z=64.     

Synthesis and properties of epoxy-anhydride polymers modified with polyfluorolakyl-substituted oxiranes in the course of curing

Epoxy-anhydride polymers based on N,N,O-triglycidyl-p-aminophenol and isomethyltetrahydrophthalic anhydride were synthesized in the presence of new active modifiers, polyfluoroalkyl glycidyl ethers. The kinetics of the reactions of the modifiers with the anhydride were studied by differential scanning calorimetry and IR spectroscopy. The physicomechanical characteristics, glass transition points, and water absorption of the polymers were determined.     

Curing of epoxy-anhydride formulations in the presence of imidazoles

Differential scanning calorimetry was used to study the reaction of isomethyltetrahydrophthalic anhydride with phenyl glycidyl ether and the curing kinetics of diglycidyl ether of diphenylolpropane in the presence of imidazoles. The deformation-strength characteristics of cured epoxy polymers were determined.     

Synthesis and some properties of heteronuclear platinum and palladium carbonyl clusters

Heteronuclear clusters of general formula [Pt_xPd_y(CO) _z] were synthesized by reaction of CO with PtCl₄ + PdCl₂ solutions in 95% ethanol at room temperature and atmospheric pressure. The products isolated were analyzed by IR spectroscopy, thermogravimetry, and X-ray powder diffraction.     

Interaction of chitosan with benzoic acid in solution and films

Chitosan films are prepared from solutions containing benzoic acid. Depending on preparation conditions, films of two types can be prepared: homogeneous optically transparent films and biphasic films containing fractal inclusions in a transparent matrix. The presence of ionic interaction between chitosan and benzoic acid in films is confirmed with the use of IR spectroscopy. The algorithm of the analysis of fractal dimensionality based on halftone images is suggested.     

Determination of the specific surface area of FORUM fluoroplastic powder by the dye adsorption from solutions

The specific surface area of FORUM fluoroplastic powder, synthesized by the partial thermal degradation of polytetrafluoroethylene followed by the separation of spherical particles from a gas condensate is estimated from the adsorption of two dyes, methylene blue and rhodamine 6G, from aqueous solutions.     

Uranyl cyanoacetate [UO<Subscript>2</Subscript>(H<Subscript>2</Subscript>O)<Subscript>2</Subscript>(NCCH<Subscript>2</Subscript>COO)<Subscript>2</Subscript>]: Synthesis,crystal structure,and absorption spectra

The U(VI) complex with cyanoacetic acid, [UO₂(H₂O)₂(NCCH₂COO)₂] (I), was synthesized from an aqueous solution, and its X-ray diffraction analysis was carried out. The crystals are orthorhombic: space group Pca2 ₁, a = 25.9605(7) Å, b = 6.7634(2) Å, c = 6.3398(2) Å, V = 1113.15(6) ų at 100 K, and Z = 4. The coordination polyhedron of the uranium atom is a distorted pentagonal bipyramid. The cations UO ₂ ²⁺ are bound into infinite zigzag chains by the bridging carboxyl groups of one of the anions of cyanoacetic acid. The carboxyl oxygen atom of the second anion, which is not involved in coordination, and the nitrogen atoms of the cyano groups form hydrogen bonds with the coordination water molecules. The layer structure of the compound is formed through the hydrogen bonds. The absorption spectra in the visible and infrared ranges of the crystalline compound are measured and analyzed.     

Synthesis and curing of epoxy-anhydride polymers modified with an oxirane of the tetrahydroquinoline series

Epoxy-anhydride polymers were prepared from diphenylolpropane diglycidyl ether and isomethyltetrahydrophthalic anhydride in the presence of a chemical modifier, oxirane of the tetrahydroquinoline series. The kinetics of the reaction of the modifier with the anhydride and the curing kinetics of the polymeric compound containing the modifier were studied. The thermal properties and water absorption of the polymers after their curing and structure formation were determined.