Chemistry

Regulation of the Physicochemical Properties of Acrylic Copolymers by Graft Polymerization onto Cellulose and Starch

Scientific literature in English from 2010 to 2019, devoted to the problem of the development of sorbents based on polymeric materials, intended for collecting spilled oil and oil products from the surface of reservoirs, was scanned and analyzed. Three most numerous classes of polymeric sorbent materials (cellulosic materials, acrylate copolymers and synthetic rubbers) were identified, and the oil sorbents proposed are characterized. Prospects of using sorbents of these classes for cleaning up the surface of reservoirs from oil spills were discussed.

Viscosity Properties of Chitosan Solutions in Glycolic Acid

Viscosity properties of chitosan solutions with molecular weights of 700 and 200 kDa in 1.5% glycolic acid were studied in a wide range of polymer concentration and ionic strength of the medium by means of capillary and rotational viscometry. The concentration dependences of the specific viscosity were plotted. The influence of the molecular mass of chitosan and the NaCl-controlled ionic strength of the medium on the hydrodynamic volume of macrochains and their polyelectrolyte properties was established. The size of a polyion with an almost completely compensated charge was estimated.

Study of Rheological Properties of Sodium Salt Solutions of Carboxymethyl Cellulose

Rheological characteristics of polymer solutions not only affect their processing, but can also influence on the structure and properties of products obtained from the solutions. This work is devoted to the study of rheological properties of sodium salt aqueous solutions of carboxymethyl cellulose in water. It is shown that the studied solutions are characterized by the presence of concentration area of unstructured semi-separated solutions without network formation.

Complexation of Polymyxin B1 Derivatives with Heparin

The method of coprecipitation from aqueous solutions at a neutral pH value was used to study the interaction of polymyxin B1 derivatives with sodium heparinate. They were compared with the initial unmodified antibiotic and with the initial antibiotic in a solution of the corresponding polymer, covalently unbound with it.

Phase Equilibria and Salting Out of Butyric Acid in the Sodium Chloride – Water – Butyric Acid Ternary System

Phase equilibria in the water–butyric acid binary system in the range of −10÷0° C and in the sodium chloride–water–butyric acid ternary system in the range of 10.0÷60.0° C were studied using the visual polythermal method. The phase diagram of the water–butyric acid binary system at −9.5° C is characterized by eutectic equilibrium, the solid phases of which being ice and butyric acid crystals. The metastable delamination range was found on the ice crystallization field, bounded by a binodal curve with an upper critical solution temperature of −3.7° C.

Assessment of Growth-Regulating Activity and Ecotoxicity of Diarylidene-Substituted Cyclohexanones

The search of new biologically active substances to be used as herbicides and plant growth regulators is carried out. The two compounds were used – 2-benzylidene-6-(m-nitrobenzylidene) cyclohexanone (1) and 2-benzylidene-6-(p-fluorobenzylidene) cyclohexanone (2). They are similar in structure, but containing different functional groups in one of the benzene rings: -NO2, and -F. Their dose-dependent effect on the germination and growth of Triticum aestivum and Barbarea vulgaris was investigated.

Improved Synthesis of 2,3,4,6-tetra-О-acetyl-α-D-glucopyranosylhalogenes and 2,3,4,6-tetra-О-acetyl-α,β-D-glucopyranose – Glycosylating Agents of Biologically Active Compounds

O,N-Glycosylation reactions are used for the synthesis of prodrugs based on various pharmaceutical substances. This, in turn, can significantly improve their pharmacokinetic and pharmacodynamic parameters, as well as reduce toxic effects. In current study, the objective was to propose new variants of the synthesis of active glycosylating agents, superior to the previously known ones in terms of the use of highly toxic substances, the anomeric composition of the products and the reaction time.

Синтез и конформационные особенности пергидропирролодиазациклоалканонов

The reactions of 4-phenyl and 4-(p-tolyl)-4-oxobutanoic acids with 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane by heating in an aprotic non-polar solvent initially proceed through a nucleophilic attack of the amino group on the carbon atom of the oxoacid carbonyl group to form the corresponding amide.

Quasi-binary Section Ag2SnS3-Sb2S3

Silver thiostannates and chalcostannates are widely used as promising functional materials which have semiconductor, thermoelectric, and photoelectric properties. The goal of this research is to study the Ag2SnS3-Sb2S3 phase diagram and determine the boundaries of solid solutions based on both components. Alloys were investigated using methods of physicochemical analysis. Based on the results of the study, a condition diagram of the Ag2SnS3-Sb2S3 system was constructed.

Synthesis and Physicochemical Properties of Grafted Copolymers of Chitosan and Acrylic Monomers

The search and analysis of English-language 2004–2019 scientific literature devoted to the graft polymerization of acrylic monomers (acrylic acid and acrylamide being examples) onto chitosan to obtain novel materials with valuable properties was made. It was revealed that radical copolymerization, with potassium or ammonium persulfate, cerium-ammonium nitrate being initiators was used for grafting. Microwave, UV radiation and gamma rays were also used. To obtain gel, a cross-linking agent (N,N’- methylenebisacrylamide) was introduced. Glutaraldehyde was also used for cross-linking.

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