Various hydroxyapatite-filled and unfilled microspheres based on lactide and glycolide copolymers were prepared. The synthesized poly(lactic-co-glycolic acid) (PLGA) samples were characterized by GPC and 1H NMR spectroscopy, the morphology was characterized by SEM. It was shown that under the tin (II) 2-ethylhexanoate catalysis the glycolide is highly active in copolymerization as compared with lactide. According to the data on weight loss and the weight average molecular weight shift of PLGA over time (pH = 6.5; t = 25 °C), an increase in the rate of microsphere destruction was noted when macromolecules were enriched with glycolic acid residues, as well as when filled with hydroxyapatite. It was shown that the rate of PLGA degradation was determined by the water-accessible surface of a sample. The rate increase in PLGA hydrolytic degradation both with an increase in glycolic acid residues mole fraction in the chain and upon filling with hydroxyapatite was the result of the microspheres’ surface hydrophilization, an increase in capillary pressure upon filling of the pores as well as of the defects with water, and an increase in the number of structural defects. Approaches to the creation of composite microspheres based on PLGA degrading at a controlled rate were proposed.

The combination of biocompatibility, biodegradability, and high mechanical strength has provided a steady growth in interest in the synthesis and application of lactic acid-based polyesters for the creation of implants. On the other hand, the hydrophobicity of polylactide limits the possibilities of its use in biomedical fields. The ring-opening polymerization of L-lactide, catalyzed by tin (II) 2-ethylhexanoate in the presence of 2,2-bis(hydroxymethyl)propionic acid, and an ester of polyethylene glycol monomethyl ester and 2,2-bis(hydroxymethyl)propionic acid accompanied by the introduction of a pool of hydrophilic groups, that reduce the contact angle, were considered. The structures of the synthesized amphiphilic branched pegylated copolylactides were characterized by 1H NMR spectroscopy and gel permeation chromatography. The resulting amphiphilic copolylactides, with a narrow MWD (1.14–1.22) and molecular weight of 5000–13,000, were used to prepare interpolymer mixtures with PLLA. Already, with the introduction of 10 wt% branched pegylated copolylactides, PLLA-based films had reduced brittleness, hydrophilicity, with a water contact angle of 71.9–88.5°, and increased water absorption. An additional decrease in the water contact angle, of 66.1°, was achieved by filling the mixed polylactide films with 20 wt% hydroxyapatite, which also led to a moderate decrease in strength and ultimate tensile elongation. At the same time, the PLLA modification did not have a significant effect on the melting point and the glass transition temperature; however, the filling with hydroxyapatite increased the thermal stability.

Linear and branched polylactides were synthesized, and photochromic polymer coatings on their basis were obtained using nitro-substituted indoline spiropyran. Spectral-kinetic experiments showed that these coatings can exhibit both positive and negative photochromism. The character of appearance of photochromism is determined by the content of branched polylactide.

Coatings on glass and poly(ethylene terephthalate) have been obtained on the basis of oligosiloxanes bearing chloromethyl and aminopropyl groups. Treatment of the coatings with amino alcohols and anhydrides of dicarboxylic acids has afforded the samples exhibiting hydrophilic properties. The use of amino alcohols containing three hydroxyl groups has favored the appearance of superhydrophilicity.

It has been established, that the introduction of ionic groups into the structure of oligosiloxanes promotes the formation of hydrophilic coatings under microwave irradiation. The hydrophilicity of the coatings increases with an increase in the irradiation power.

In this study, new biodegradable and biocompatible amphiphilic polymers were obtained by modifying the peripheral hydroxyl groups of branched polyethers and polyesters with organosilicon substituents. The structures of the synthesized polymers were confirmed by NMR and GPC. Organosilicon moieties of the polymers were formed by silatranes and trimethylsilyl blocks and displayed hydrophilic and hydrophobic properties, respectively. The effect of the ratio of hydrophilic to hydrophobic organosilicon structures on the surface activity and biological activity of macromolecules was studied, together with the effect on these activities of the macromolecules' molecular weight and chemical structure. In particular, the critical micelle concentrations were determined, the effect of the structure of the polymers on their wetting with aqueous solutions on glass and parafilm was described, and the aggregation stability of emulsions was studied. Finally, the effect of the polymer structures on their antifungal activity and seed germination stimulation was examined.

A series of poly(β-amino esters) were synthesized using the Michael addition reaction from 1-(3-aminopropyl)silatrane and glycol diacrylates. The structure of the resulting olygomers was confirmed by means of 1 H NMR spectroscopy. Using acetylsalicylic acid as a model drug, the ability of synthesized olygomers to bind carboxyl-containing physiologically active compounds was shown. Synthesized polymers have been found to possess biological activity characteristic of low molecular 1-(3-aminopropyl)silatrane.

Objectives. Biologically active polymeric surfactants are a new promising class of macromolecules that can find application in medicine, cosmetology, and agriculture. In this study, a number of new biologically active amphiphilic polymers based on branched silatrane-containing polyesters and polyethers were obtained, and their surface-active properties were investigated.Methods. The branched polymers were represented by polyethers and polyesters, obtained respectively via the anionic polymerization of 1,2-epoxypropanol or a combination of equilibrium polycondensation and ring opening polymerization. The polymers were modified with 3-isocyanopropylsilatrane and trimethylethoxysilane to obtain the amphiphilic compounds containing silatrane groups bonded to the polymer backbone by the urethane bond. The structure of the synthesized polymer silatranes was confirmed via nuclear magnetic resonance spectroscopy and gel permeation chromatography. The surface active properties of all the copolymers obtained were investigated in connection with their obvious amphiphilicity. In particular, the formation of micelles in aqueous solutions is such a property. The critical micelle concentrations were determined by a method of quenching the fluorescence of the polymers.Results. It was shown that the values of the critical micelle concentrations and the hydrophilic-lipophilic balance values of polymers determined by the Griffin equation correlate well with each other. A linear relationship between the hydrophilic-lipophilic balance and the critical micelle concentrations was established. At the same time, polyether-based polymers generally showed higher critical micelle concentrations than polyester-based polymers, although the hydrophilic-lipophilic balance values for polymers of different series, but with close degrees of substitution, were close. It was found that the use of all synthesized polymers as stabilizers of direct and reverse emulsions leads to an increase in the aggregative stability of both types of emulsions. The stability of emulsions depended both on the degree of substitution of peripheral hydroxyl groups of polymers by silatranes and on the molecular weight and structure of the branched block of polymers. The stability of direct emulsions increased for all polymers, while that of inverse emulsions decreased with an increasing degree of substitution of hydroxyl groups by silatranes. The increase of the branched block molecular weight led to an increase of droplet sizes for both direct and inverse emulsions. The smallest droplet size for direct and inverse emulsions was obtained using polymers with low molecular weight branched polyester blocks as surfactants.Conclusions. The results obtained prove the possibility of creating polymer surfactants containing silatrane groups. By varying the structure of the polymer, its molecular weight and the degree of substitution of peripheral functional groups, it is possible to obtain surfactants with desired surface properties.

The possibility of synthesizing silatrane-containing polymers was investigated using three different synthetic methods: the formation of silatrane fragments from polymers with trialkoxysilyl groups, the copolymerization of silatrane-containing monomers, and the reaction of silatranes with functional copolymers. The obtained polymethacrylate copolymers were characterized using gel permeation chromatography, IR and NMR spectroscopy. It was shown that depending on the synthesis scheme used, polymers were obtained in the form of three-dimensional structures or soluble products. It was established that the molecular weight of the synthesized polymers depended significantly on both the content of silatrane fragments and the synthesis technique used. It was shown that the modification of linear carboxyl-containing copolymers by silatranes allows the synthesis of high-molecular polymers with a high content of silatrane fragments. For the synthesized polymers, thermal properties were investigated, and the hydrophobicity of the surface of polymer films was also evaluated. It was found that all the studied polymers did not have clear melting and crystallization temperatures. The polymers were stable in an inert atmosphere up to 270-280 °C, whereas in air they decomposed at lower temperatures with the restructuring of the macromolecular skeleton and the formation of highly heat-resistant silicone structures. An increase in the content of silatrane moieties in the copolymers led to an increase in the hydrophilicity of polymers.

1МИРЭА – Российский технологический университет (Институт тонких химических технологий имени М.В. Ломоносова), Москва 119571, Россия 2АО «Научно-исследовательский институт химии и технологии полимеров имени академика В.А. Каргина с опытным заводом», Нижегородская область, г. Дзержинск 606000, Россия 3Московский государственный университет имени М.В. Ломоносова, Химический факультет, Москва 119899, Россия @Автор для переписки, e-mail: o.a.satskevich@yandex.ru

Magnetite nanoparticles have been obtained in hybrid micelles of polylactide-block-polyethylene oxide (PL- b -PEO) and sodium dodecyl sulfate (SDS) in a one-stage process. Dynamic light scattering, transmission electron microscopy, and small-angle X-ray scattering data show that hybrid micelles form micellar associates, and the size of magnetite nanoparticles in hybrid micelles of the block-copolymer varies from 0.5 to 10 nm. The specific magnetization of solid samples has been measured.

The linear-branched copolylactides containing linear side poly(ethylene oxide) blocks are synthesized and characterized. The critical micelle concentrations and the aggregative stability and the dispersity of oil/water emulsions stabilized by these copolymers are estimated. The polylactide microparticles are obtained by emulsification followed by evaporation of an organic solvent using acetylsalicylic acid as a model drug. The structure of copolylactides strongly affects the properties of the microparticles. On one hand, the presence of large poly(ethylene oxide) blocks in the linear-branched macromolecules leads to the formation of colloidal systems with a higher aggregative stability of emulsions and a lower size of particles, and on the other hand, the microparticles formed from these copolymers possess a lower incorporation efficiency relative to water-soluble low-molecular-mass compounds and the profile of the release of these compounds is nonlinear and contains the region of accelerated release.

Linear-hyperbranched co(polylactides) containing hyperbranched polyglycerol (PG) block were synthesized and characterized. An estimate of critical micelle concentration as well as aggregative stability and droplet sizes in the emulsion stabilized by the obtained polymers was made. It was shown that an architecture of linear-branched co(polylactides) defines its surface-active properties and characteristics of dispersion systems obtained from it. With an increase in PG block content in copolymers, critical micelle concentration and aggregative stability of emulsions increase. Polylactide microparticles were obtained by organic solvent evaporation technique using acetylsalicylic acid as a drug model. Some properties of microparticles, such as size, incorporation efficiency and in vitro release of immobilized substance, were examined. It was noticed that branching architecture of co(polylactides) has a significant influence on the properties of microparticles. On the one hand, the presence of large PG blocks in linear-branched macromolecules results in the formation of colloidal systems with higher aggregative stability of emulsions and smaller particle size; on the other hand, microparticles formed from such copolymers have lower incorporation efficiency towards water-soluble low-molecular-weight compounds and nonlinear release profile for these substances with a segment of accelerated primary release.