B. A. Izmailov

Photochromic silicon polymers based on 1,2-dihetarylethenes

Silicon-containing three-dimensional polymers (coatings) exhibiting photochromic effects have been synthesized on the basis of 1,2-dihetarylethenes with N-hydroxyethyl and N-allyl groups, polysiloxanes, and polysilazanes. Irradiation of the coatings at ∼380 and >500 nm induces reversible transitions between colorless open and colored cyclic forms of the polymers. The efficiency of photochromic transformations in the coatings is lower than that in the initial dihetarylethenes and is dependent on the structure of the polymer matrix and the content of photochromic fragments.

Synthesis of poly(arylate-siloxane)s in supercritical carbon dioxide

The reaction between poly(4,4′-isopropylidene-2,2′-diphenylene (tere)isophthalate) copolymer and 3-aminopropyltriethoxysilane was investigated in supercritical carbon dioxide at 150 atm and 100° C. It was found that ester bonds in the copolyarylate undergo aminolysis under the above conditions to give rise to the formation of siloxane-containing amides, whose interaction with phenol groups of the macromolecules and moisture affords an insoluble poly(arylate-co-siloxane) fraction. Under the action of moisture, three-dimensional structures containing polyarylate and polysiloxane fragments are formed in the soluble fraction of the copolymer via the combined hydrolysis of ethoxysilane groups. The formation of the siloxane network affects the properties of the polymers. In particular, thermomechanical and thermal tests showed that sample deformation at 250°C decreases from 80 to 15%, while the carbon residue at 725°C increases twofold as compared to that of an initial polyarylate sample.

Photochromic fulgimide-containing silicones immobilized on the surface of polyarylate

Photochromic coatings immobilized on the surface of polyarylate films are prepared on the basis of fulgimides, oligosiloxanes, and oligosilazanes. The irradiation of coatings with UV light at a wavelength of @380 nm and visible light at a wavelength above 500 nm results in photoinduced reversible transitions between open and colored cyclic forms. Photochromic polymer films with the most acceptable characteristics are obtained from fulgimide-containing oligoaminosiloxane and oligovinyldimethylsilazane. It is found that the photosensitivity of these films is higher than that of similar films based on 1,2-dihetarylethenes.

Synthesis and fungicidal properties of new bisphenol-containing oligoorganosiloxanes

New fungicidal and antimicrobial siloxane oligomers were prepared on the basis of γ-aminopropyltriethoxysilane and a series of bisphenols. Chemical immobilization of these oligomers on the surface of various fabrics was studied with the aim to develop textile materials resistant to microbiological degradation.

New conjugated poly(aryleneethynylenes) with main-chain photochromic units

New photochromic poly(aryleneethynylenes) have been synthesized on the basis of dibromodithienylmaleimide and bisacetylenes under the conditions of the Sonogashira reaction. Molecular masses and polydispersities of the poly(arylene ethynylenes) vary over the following ranges: M w = 19 150–32 650, M n = 12 000–19 200, and M w/M n = 1.47–1.70; the glass-transition temperatures are in the range 208–230°C; and the 10% weight-loss temperatures in air and argon are in the ranges 330–370 and 550–660°C, respectively. All poly(aryleneethynylenes) exhibit photochromic properties in both solutions and films. It has been shown that, when photochromes are incorporated into a polymer matrix, the efficiency of their photoinduced coloration diminishes, irrespective of whether they are fragments of macromolecular chains or components of polymer solutions.

Coatings and surfactants based on oligovinylsiloxanes

Silicate glass and cotton fabric are hydrophobized via treatment of their surface by vinyltriethoxysilane and oligovinylsiloxane. The data of electron microscopy for chemical analysis and the values of contact angles suggest that the hydrophobicity of the surface layer develops via the polymerization of vinyl groups. The arrangement of vinyl groups in neighboring units in oligovinylsiloxane is favorable for formation of a more uniform solid coating with enhanced hydrophobicity. The use of oligovinylsiloxane and its derivatives with amino and carboxyl groups as surfactants in the heterophase polymerization of styrene makes it possible to obtain stable suspensions with a narrow particle size distribution.

The mechanism of chemical modification of artificial fibers based on cellulose derivatives

A fabric based on cellulose derivatives has been hydrophobized via coating with oligochloromethylethoxysiloxane and then treated with butyl alcohol, benzyl alcohol, and higher fatty alcohols. With the use of X-ray photoelectron spectroscopy, it has been shown that the reaction of alcohols with the siloxane coating proceeds through the exchange of ethoxysilane groups for higher alkoxy groups, whereas the expected reaction of chloromethyl groups with alcohols (the Williamson reaction) does not occur under the chosen conditions.

Polymeric materials with grafted luminescent organosiloxane coatings

A procedure was developed for preparing polymeric materials with grafted luminescence organosiloxane coatings containing conjugates of rare-earth elements with various color spectra.