The grafted copolymerization of 2-hydroxyethyl methacrylate to polyvinylpyrrolidone in the presence of mineral fillers (hydroxyapatite, montmorillonite and wollastonite) under ultrasound has been investigated. The effect of ultrasound, nature and amount of mineral filler on the polymerization rate and composition of copolymers has been determined. Ultrasound substantially intensifies the polymerization process and actively affects the formation of the copolymer composition. Under its action, a porous structure of composites is formed, even without adding special foaming agents. The obtained results were used to improve the technology of obtaining osteoplastic porous composites.
the impact of ultrasound on the laws of the polymerization of methacrylic ester compositions with polyvinylpyrrolidone and mineral fillers has been investigated. The influence of ultrasound, the nature and amount of inorganic filler, the intensity of ultrasound on the rate of polymerization, the composition of the copolymers and the porosity of the composites has been established. It is confirmed that ultrasound significantly intensifies the polymerization and actively influences the formation of the composition of the copolymers.
The influence of technological factors on the preparation of silver nanoparticles has been studied when using polyvinylpyrrolidone as a reducing agent and stabilizer of the dispersion of nanosized particles. The effect of temperature, polyvinylpyrrolidone content and concentration of silver ions on the kinetics of silver reduction as well as the shape and size of nanoparticles has been determined. Based on the UV study of reagent solutions, the conclusion was confirmed that polyvinylpyrrolidone of a higher molecular weight is a more effective reducing agent of silver. The way of interaction between silver salts and polyvinylpyrrolidone with formation of vinylsuccinimide units in the structure of macromolecules has been proposed. The influence of the nature of silver salt on the shape and size of silver nanoparticles has been established. In the case of the use of silver nitrate, the silver nanoparticles are more homogeneous and they are mainly formed as triangular prisms and polyhedra of different sizes. In the case of the reduction of silver using silver acetate, the formed nanoparticles have a predominantly spherical shape. Nanosized particles with a wide size distribution are formed at the ratio of polyvinylpyrrolidone:AgNO3>20:1 (wt.). As this ratio decreases, the stabilization of the formed nanoparticles weakens, which leads to an increase in the size of silver particles up to the formation of nanocrystals with a size of several hundred nanometers. Silver-containing composites based of the polyvinylpyrrolidone copolymers filled with hydroxyapatite in the form of porous blocks and films were synthesized, and their bactericidal and fungicidal properties were investigated. The developed porous composites can be used in medicine as osteoplastic to replace damaged bone tissue.
The regularities of obtaining silver nanoparticles in the presence of polyvinylpyrrolidone, which was both a reductant and a stabilizer of nanoparticle dispersion, have been studied. The influence of such factors as temperature, polyvinylpyrrolidone amount, concentration and nature of silver salts on the shape and size of nanoparticles has been established. The chemistry of the silver salts and polyvinylpyrrolidone reaction with the formation of vinylsuccinimide units in the structure of macromolecules has been proposed, which is confirmed by the results of IR spectroscopy. It has been established that the shape and size of silver nanoparticles are influenced by the silver salt nature. If silver nitrate is used for the reduction reaction, silver nanoparticles are formed mainly in the form of triangular prisms and polyhedra. When using silver acetate, nanoparticles of spherical shape are predominantly formed. High-quality nanoparticles are formed if the mass ratio of polyvinylpyrrolidone : silver salt is more than 20. The decrease in this ratio deteriorates the stabilization of the formed nanoparticles and increases the particle size of silver until the formation of nanocrystals several hundred nanometers in size. The kinetics of silver salts and polyvinylpyrrolidone reaction has been studied in a solution. The reaction was found to occur faster with increasing temperature and the polyvinylpyrrolidone amount. Silver reduction reaction by polyvinylpyrrolidone was used to provide fungibactericidal properties of hydroxyapatite-filled osteoplastic porous composites based on polyvinylpyrrolidone copolymers with methacrylic esters.
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