Investigation of the structure and properties of polyurethane compositions modified with metal-containing compounds

New cross–linked and linear polyurethane compositions with different content of various reactive metal[Ni,Zn,Cu]inorganic modifiers (MIM) were synthesized. The results of IR spectroscopy confirm the reaction and structural reorganization in the system under the influence of MIM. Thus, in the region of stretching vibrations of NH groups of the urethane fragment, a shoulder increase was noted in the region of weakly bound stretching vibrations of NH groups at 3456 cm-1 and a new band at 4314 cm-1 appears, which indicates the presence of hydrogen bonds with the chlorine ion CuCl2. The presence of MIM in polyurethane leads to a shift of valence vibration of urethane group band νС =O to the region of 1723 cm-1 and the appearance of an intensive shoulder 1711 cm-1, which indicates the formation of a coordination bond C = O → Cu[Cl2]. The appearance in the IR spectrum of the polymer with MENM content of three new bands with maximums (530, 558 and 637) cm–1 indicates the formation of a coordination bond N → Cu. It was shown that the presence of transition metals dichlorides in the polymer structure provides opportunities for target production of polyurethane compositions with a set of specified properties, namely: fungicide properties, which were provided by the presence of Zn- and Cu-chlorides, photostability which was provided by the presence of Ni-chloride. In this case, the incorporation of active compounds into the structure of the polymer excludes the diffusion of MIM on the surface of the material with subsequent removal and thus prolongs the protective functions of the coating – resistance to biocorrosion, UV radiation, chemical agents, heat resistance while maintaining high adhesion / cohesion. Keywords: polyurethane compositions, cross-linked, linear, inorganic modifiers, coatings, adhesion, stabilyty, environment.

IR Spectroscopy of Polypropylene Fibrous Carrier before and after its Surface Modification with Metal Nanoparticles

In this paper, we present an IR spectroscopy study of the molecular and supramolecular structure of the polypropylene fibre, used as a metal nanoparticle carrier, by the example of nanoparticles of tin dioxide. The aim of this work is to investigate the changes in the chemical structure of the polypropylene melt-blown web when modified with the tin dioxide nanoparticles. The paper shows that the metal-oxygen valence vibration bands appear in the IR spectra of modified polypropylene fibrous carriers. At the same time, the carrier material remains stereoregular and possess a helical structure.

Electro-Optical Parameters of Some Benzene Derivatives obtained by Molecular Orbital Calculations

A series of structural and physico � chemical properties of some monosubstituted halogene � derivatives of benzene were analyzed by using HyperChem software package. The bond lengths, the angle between the covalent bonds, atomic charges, the symmetry class, the energies of the ground and excited states, the dipole moments, the polarizabilities, the wavelengths of the electronic transitions and the corresponding oscillator strengths have been obtained and correlated with experimental data published for the studied compounds. The computed molecular polarizability a is directly correlated with the measured halogene atomic electronegativity. A polynomial dependence of order two was evidenced between the valence vibration wavenumber of C-X bond, experimentally determined and the computed polarizability.

Tieftemperatur-Raman-Messungen an bewegten Proben bei 10 K am Beispiel der Isotopomeren Cs2[Pt35Cln37Cl6-n, n = 0-6 / Low-Temperature Raman Measurements on Moved Samples at 10 K Exemplified by the Isotopomers Cs2[Pt35Cln 37Cl6-n], n = 0-6

A technique to record Raman spectra of deeply coloured solids at low temperature (10 K) is described, using a closed cycle He-cryogenerator and moving the cell by an excentric attachment. The spectroscopic resolution is considerably enhanced as compared to room temperature or 80 K measurements. This is obvious from splittings of Raman lines observed at 10 K on the isotopomers Cs2[Pt35Cln37Cl6-n], n = 1 -5, which have been prepared by stereospecific ligand exchange reactions. As a consequence of lowered symmetry the degenerate valence vibration v2(Eg, Oh) is split into two lines for the isotopomers belonging to the point groups D4h, C4v and C2v. The isotopic effects calculated by normal coordinate analysis are in good agreement with the observed frequencies.

N=N Vibrational Frequencies and Fragmentation Patterns of Substituted 1-Aryl-3,3-Dialkyl-Triazenes: Comparison with other High-Nitrogen Compounds

The influence of substitution pattern and electronic structure on the N=N stretching frequencies of compounds containing three to six linearly connected nitrogen atoms has been investigated by FT-IR and Raman spectroscopy. For a series of 1-phenyl-3,3-dialkyl-triazenes, Phe-N1=N2-N3 R2, shifts in the two valence vibrations of the triazeno group are studied with respect to the type and position of substituents at the aromatic ring, and for various alkyl substituents at N3. The N1=N2 stretching frequency is lowered by electron-withdrawing substituents at the aromatic ring; this effect is most pronounced for para-positioned substituents. A decrease in the N1=N2 bond order, and of the associated valence vibration, is also observed upon introduction of heavier N3-alkyl substituents, due to an inductive effect. Changes in vibrational frequencies are correlated with characteristic fragmentation patterns in the mass spectra of these compounds, where two degradation routes subsequent to ionization at the nitrogen atoms N1 and N2 have been observed. For the investigated pentazadiene derivatives, a weaker dependence of the N=N vibrational frequencies on the substituents is found. Mass spectra are interpreted in terms of two typical fragmentation pathways, involving a McLafferty rearrangement.

A study of the medium effect of mixed solvents; The cyclohexane-acetone system

Wavenumbers of the S-O bond valence vibration of dimethyl sulphoxide, wavenumbers of the longest wavelength band maxima of 3-nitro-N,N-dimethylaniline and 2,6-diphenyl-4-(2,4,6-triphenyl-1-pyridinio)phenoxide and rate constants of the reaction of triethylamine with ethyl iodide measured in mixtures of cyclohexane and acetone were correlated with functions of relative permittivity and refractive index of these media and mutually with each other.

IR spectra of methyltetrosides and their monomethyl ethers in the region of valence vibration of hydroxyl groups

IR Spectral absorption bands ν(OH) (3 700 to 3 400 cm-1) of the both anomers of methyl D-threofuranoside, methyl-D-erythrofuranoside, and their monomethyl ethers have been studied in dilute tetrachloromethane solution. For these 11 compounds positions and intensities of individual bands are discussed with respect to possible formation of intramolecular hydrogen bonds.