Vladimir Syromyatnikov

Some Light-Sensitive Imide Molecular Systems with the Determined Functional Properties

Abstract Some unconjugated molecular systems with different kinds of intramolecular energy transfer are proposed and discussed.

Synthesis and Electrooptical Properties of Metal-Containing Azopolymers

We propose new structures of polymeric composites with changeable optical characteristics (transmission and/or reflection of polarized light) under the influence of magnetic and/or electric fields. The new monomers 4-methacroyloxy-(4′-carboxy-3′-hydroxy)-azobenzene, 4-methacroyloxy-(4′-carboxy-3′-hydroxy)-2-nitroazobenzene,and 4-methacroyloxy-(4′-carboxy-3′-hydroxy)-2-diethylamino-azobenzene, their complexes with Co, and polymers based on their base are synthesized. The influence of the electric field on the absorption spectra of films of the new metal-containing azopolymers is investigated. The effect of an electric field on the transmission of a linearly polarized light through the films is revealed. This effect is determined by the re-orientation of the dipole moments of azobenzene groups which is induced by a polarized light under the action of an electric field. The increase of the dipole moments of azobenzene groups due to the introduction of donor and acceptor substituents reduces the influence of Co ions on the electrooptical properties of polymeric films.

Photochromic Polymers Based on Methacrylic Azoesters

ABSTRACT The new polymers and copolymers based on methacrylic acid azoesters with substituents of different nature and spacer length were synthesized. The difference in chemical structure of the side chains was expected to influence on the difference in the supramolecular structure of azobenzene moieties. Due to flexibility of alkyl spacers, the azobenzene fragments can rotate relatively freely in the polymeric matrix.

Synthesis and Electrooptical Properties of Metal-Containing Azopolymers. The Influence of Steric Factors on the Electro-Optical Effect in Polycomplexes of Azobenzene Derivatives with Cobalt

We propose new structures of metal-containing azopolymers with changeable electro-optical properties in consequence of different coordination metal ions. The new monomers – 4-methacroyloxy-(4′-carboxy-3′-hydroxy)-azobenzene, 4-methacroyloxy-2′-carboxy-azobenzene and their complexes with Co and polymers based of these ones are synthesized. The influence of the electric field on the absorption spectra of new metal-containing azopolymers films are investigated. Electro-optical properties of polymeric films is determined by the re-orientation of dipole moments of azobenzene groups photo induced by polarized light in the electric field. Increase of structural inflexibility by the photo isomerization of azobenzene groups decrease the electro-optical effect value.

Poly(vinyl alcohol)-Graft-Polyacrylamide with Different Grafts Number and Length as Studied by 1H NMR Spectroscopy

ABSTRACT The influence of poly(vinyl alcohol) matrix on stereoregularity of replica polyacrylamide chains in matrix radical graft copolymerization process when varying the grafts number and molecular weight is studied by high-resolution NMR spectroscopy. It was ascertained that the microstructure of formed polymer at homopolymerization and matrix copolymerization processes are not differed. 1H NMR spectroscopy suggests a few contacts of graft chains with the main chain through H-bonding in intramolecular polymer-polymer complex forming in macromolecules of investigated poly(vinyl alcohol)-to-polyacrylamide graft copolymer.

About the compatibility of polymer components in polymer complexes based on poly(acrylamide) and poly(vinyl alcohol)

The issue of applying the usual concepts of polymer compatibility to nonstoichiometric PVA/PAA mixtures of chemically complementary poly(vinyl alcohol) and poly(acrylamide), which form in water solution InterPC (intermolecular polymer complex) stabilyzed by H-bonds, and PAA to PVA graft copolymers (PVA-PAA N ) with different grafted chains number N, that are IntraPC (intramolecular polymer complexes) is discussed. PVA and PAA are compatible on molecular level. At the same time PVA/PAA mixture (50/50 W/W) is characterized by heterogeneous structure consists of InterPC with φ char =9g PVA /g PAA and the excess of unconnected PAA. In the case of IntraPC, yet, only PVA-PAA N , where N=25, is characterized by a single glass transition temperature (Tg). At larger values of N separate PAA domains form giving rise to the corresponding Tg. These results are discussed in view of IntraPC structure peculiarities as a function of N investigated by IR spectroscopy.

Studies on aging and intrachain stabilization of styrene-based polymeric materials

Abstract This paper describes some results of an artificial and natural aging of polystyrene-based materials. Two mechanisms of aging–thermal destruction and photooxidation are discussed. There are two means of stabilization: with additives and with chemically bonded stabilizers. The second way is preferable because it gives a solution to the compatibility problem. New monomers as intrachain stabilizers are proposed: methacrylic esters of aminophenol derivatives, with acylamino and imide groups, can be readily copolymerized with styrene. Their monomer units in the chain can increase the thermal stability of styrene polymers and copolymers at high temperatures. Also, they can act as photostabilizers due to the processes of the intramolecular energy transfer between the aromatic systems in the monomer unit. Such stabilization is not accompanied by any chemical changes in the system when the last one is illuminated.

Exciton Transport and Destruction - Stabilization Processes in Styrene-Based Polymers

Abstract Some variants of using the excitation energy transfer for the stabilization of polymers are examined. Intramolecular photostabilizers acting due to exciton trapping are proposed.

Photoinduced Orientation of Azobenzene Groups in Polymer Films. Characterization by UV/Visible Spectroscopy

We study the kinetics of the photoinduced orientational ordering of two methacrylic polymers containing different azobenzene groups with both electron-donor and electron-acceptor substituents under irradiating them at two different wavelengths. For the experimental study of the orientational distribution in polymer films, we use the method based on absorption measurements. It is found that azofragments are oriented by either the photoorientation or photoselection mechanism depending on the wavelength. The components of the order parameter tensor of azobenzene fragments are estimated for the initial state and after different doses of irradiation.

Temperature Influence on Properties of Side-Chain Polymethacrylates with Azobenzene Mesogenic Groups and Their Polycomplexes with Cobalt (II)

Azopolymers and polycomplexes with cobalt based on them are synthesized, thermal behavior of the side chain polymethacrylates and their polycomplexes containing substituted azobenzene units as mesogens attached directly to the polymeric backbone and the influence of temperature on the photoelectric effect in films of these materials are investigated. The influence of the electric field on the transmission of polarized light is attributed to the appearance of forces affecting the dipole moments of photoisomers of azobenzene groups and metallic ions. The synthesized polymer materials showed a good thermal stability. The introduction of substituents of the different nature or spacers decreases the influence of metallic ions on the electro-optical properties of polycomplex films.