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The production of new effective hemostatic materials based on a polymer composition of modified chitosan with a three-dimensional cross-linked structure as a polymer matrix and calcium ions coordinated to it is addressed. The optimum concentration of calcium ions in the chitosan-based composition was established as 10 – 20 mM and ensured an effective in vitro blood coagulation time of 40 sec. Compositions of chitosan succinate and chloride in addition to chitosan in solutions with nicotinic acid were shown to have effective hemostatic activity. Statistical differences in the effects of various calcium salts on the blood coagulation time were not found. In vivo tests showed that a chitosan-based composition was effective for stopping bleeding of any degree of severity, both with external and internal injuries to tissues.

Three new organoselenium compounds are synthesized: N-phenyl-2-(2-thienylacetyl)hydrazinecarboselenoamide (I), 4-phenyl-5-(2-thienylmethyl)-2,4-dihydro-3H-1,2,4-triazole-3-selone (II), and 3,3'-di[4-phenyl-5-(2-thienylmethyl)-4H-1,2,4-triazolyl] diselenide (III). Two of them (compounds II and III) are characterized by X-ray diffraction analysis (CIF files CCDC nos. 1956602 (II) and 1956603 (III)). Compound II crystallizes in the monoclinic crystal system (space group P21/n) with two crystallographically independent molecules A and B being different conformers relative to rotation about the NTrz–CTrz–C(H2)–CTph bond, where Trz is triazole and Tph is thiophene (gauche-A (51.4(3)°) and cis-B (4.2(4)°)). In the crystal of compound II, molecules A and B form chains along the crystallographic axis a due to strong hydrogen bonds N–H···Se. Then the chains are bound into a three-dimensional framework via intermolecular nonvalent interactions Se···S (3.3857(11) A). Owing to the anomeric effect, diselenide III is characterized by the typical gauche conformation of the substituents at the Se–Se bond (torsion angle СSeSeС 83.5(4)°) stabilized by a weak intramolecular hydrogen bond С–H···π. In the crystal of compound III, the molecules form chains along the crystallographic acid b due to intermolecular noncovalent interactions Se···π(C–C) (3.404(6) and 3.458(12) A), Se···Se (3.8975(11) A), and S···N (3.250(5) A). Bactericidal and fungicidal activity of the synthesized compounds is studied.

Grafted copolymers of gelatin and polymethyl methacrylate are synthesized using the tributylboron–oxygen initiating system in an aqueous dispersion at 60°C. The products are characterized by IR spectroscopy and gel permeation chromatography. The proportion of polymethyl methacrylate in the copolymer is 2–60% and increases with a higher concentration of alkylborane in the initial mixture. The particle size of the aqueous dispersions of the copolymers determined by dynamic light scattering exceeds the particle size of gelatin. The thermogravimetric curves of the copolymers are similar to those of gelatin, with thermal stability tending to increase with a higher concentration of tributylboron. All the copolymers are biodegradable by fungi.

Thermal analysis of samples of chitosan–poly(methyl acrylate) block copolymer after exposure to electromagnetic fields, ultraviolet radiation, ultrasound, and biodestructive agents is performed for the first time by means of differential scanning calorimetry in the range of 250–510 K and thermogravimetry in the region of 300–850 K. It is shown that the combined effect of physical factors and biodestructive agents alters certain physicochemical properties: the temperatures of physical transformations, the temperatures of the onset of thermal degradation, and the nature of thermal decomposition.

The heat capacity and the temperatures and enthalpies of physical transformations of the alternating terpolymer of carbon monoxide, ethylene, and 1-butene (the content of butene units is 10.7 mol.%) were studied by adiabatic and differential scanning calorimetry in the temperature range from 6 to 520 K. The energy of terpolymer combustion was measured at 298.15 K on an calorimeter with an isothermal shell and static bomb. The standard thermodynamic functions C°p(T), H°(T)–H°(0), S°(T)–S°(0), and G°(T)–H°(0) for the range from Т → 0 to 400 K, the standard enthalpy of combustion, and the thermodynamic parameters of formation of the partially crystalline CO—ethylene—1-butene terpolymer at 298.15 K, as well as the thermodynamic characteristics of its synthesis in the range from T → 0 to 400 K were calculated.

Block and graft copolymers of chitosan with methyl acrylate, 2-ethylhexyl acrylate, 2-hydroxy- ethyl methacrylate, 2-hydroxypropyl methacrylate, and styrene with different spatial orientations of natural and synthetic chains and molecular masses are synthesized. The effects of the structures of the copolymers on the physicomechanical properties of their films and their biodegradability by micromycetes are revealed.

The influence of the molecular mass of chitosan and the thermodynamic quality of the solvent on the dimensional characteristics of silver nanoparticles during their in situ formation via UV reduction of silver ions from the dopant silver nitrate dopant in a chitosan-stabilizing solution is investigated. The possibility to regulate the sizes of silver nanoparticles from 8 to 12 nm via changes in the molecular mass of the stabilizer is shown.