It is shown that during the copolymerization of methyl methacrylate with the surfactant comonomer α,ω-dipropylmethacrylatep olidimethylsiloxane with the number of repeating dimethylsiloxane units n = 20 (DPMPDMS), strong interfacial adsorption layers are formed on the surface of polymer–monomer particles formed from microdrops, ensuring the stability of particles to various types of influences.

New methods for producing artificial polyetherimide suspensions in the presence of domestic cationic surfactants, their mixtures, and mixtures of cationic and organosilicon surfactants were proposed. The effect of the polymer concentration in the initial solution and conditions of emulsion dispersion on the stability and particle size of the final polymer suspensions is shown. The colloidal chemical properties of the obtained polymer suspensions are considered. Conclusions about the influence of the nature and concentration of surfactants on the stability of the obtained suspensions are drawn. When using a mixture of cationic and organosilicon surfactants, polymer suspensions stable during production and storage are formed, which is explained by the formation of structural mechanical and electrostatic stability barriers in the surface layers of the particles.

The elongation of the oligodimethylsiloxane chain in a wide range of values (from 10 to 136 units) and, correspondingly, an increase in the concentration of carboxyl groups (from 2 to 22) in the composition of organosilicon surfactants with a comb-like structure significantly affects the surface activity and interfacial layer thickness, which increase from 3.7 to 15.7 mN m 2 mol −1 and from 2 to 13 nm, respectively. The polymer suspensions obtained in the presence of the studied organosilicon surfactants (polymethyl methacrylate) are characterized by a narrow particle size distribution. The average particle diameter depends slightly on the oligodimethylsiloxane chain length and concentration of carboxyl groups in the surfactant molecules but changes significantly from 0.4 to 1.7 µm with an increase in the monomer concentration in the starting system from 10 to 20 wt.%. The resulting polymer microspheres are characterized by a hydrophilic surface due to a high content of carboxyl groups on the surface.

In this work mechanism of polymer particles formation during styrene heterophase polymerization in the presence of waterinsoluble organosilicon surfactant was investigated. Dependency between monomer conversion rate from early stages of polymerization and particle diameters change, molecular weight, particle size and molecular weight distribution was analyzed. The effect of the gel effect and Ostwald maturation on particle diameter and polymer molecular weight was evaluated.

The paper shows the similarity of kinetic regularities of vinyl monomers polymerization in the presence of Laprol 6003, regardless of the degree of solubility of the monomers in water. It is assumed that this feature of polymerization is due to the same mechanism of formation of polymer-monomer particles (PMP) – from monomer microdroplets. The interfacial adsorption layer of PMPs, the main site of polymerization, is formed from a surfactant adsorbed from the bulk of the monomer phase and a polymer formed in the adsorption layer upon initiation of polymerization. The formation of complex structures in the interfacial adsorption layer of particles, the incompatibility of the surfactant and the resulting polymer, and high viscosity cause the formation of a strong interfacial layer that ensures the stability of polymer suspensions from the early stages of polymerization.

The article presents data on the study of the polymerization temperature effect on the properties of polymer suspensions (particle diameter, particle size distribution and aggregate stability) obtained in the presence of water-insoluble organosilicon surfactants. The effect of temperature was studied during heterophase polymerization of styrene and methyl methacrylate in the presence of organosilicon surfactants of various structures with terminal amino and glycidoxy groups (alpha, omega-bis (trimethylsiloxy-oligodimethylmethyl (3-aminopropyl) siloxane (PMADMS(1)) and alpha, omega-bis [3-glycidoxypropyll poly-dimethylsiloxane (PDMS (CHOCH2)). Polymerization was carried out in different temperature conditions. The dependence of the polymerization rate and particle diameter on the synthesis temperature was revealed. With increasing temperature, the rate increases, and the particle diameter decreases (from 1.1 mu m to 0.4 mu m). It was shown that the activation energy of styrene polymerization in the presence of organosilicon surfactants of various structures is 25.4 and 33.4 J/mol, which is close to the values usually observed during radical heterophase polymerization. A decrease in the polymerization temperature leads to an increase in the induction period on the conversion/time kinetic curves. A detailed study of the initial stage of polymerization of methyl methacrylate at different temperatures showed that the particle diameter is determined at the initial stage of polymerization and depends significantly on the temperature of the process. In the case of the synthesis of polymer suspensions at a constant temperature throughout the entire polymerization process, the temperature value does not significantly affect the aggregate stability of the obtained polymer particles. In this case, the aggregate stability of polymer suspensions is influenced by the rate of an interfacial adsorption layer formation from molecules of an organosilicon surfactant and polymer, which is formed at the initial stage of the polymerization process.

Objectives. To create stable artificial polymer suspensions with a positive charge of particles based on polycarbonate and polymethyl methacrylate using cationic surfactants and organosilicon surfactants.Methods. The size of droplets and polymer suspension particles was determined by photon correlation spectroscopy (dynamic light scattering) using a Zetasizer NanoZS laser particle analyzer (Malvern, UK).Results. Domestic cationic surfactants Katamin-AB and Azol-129 were found to be capable of producing stable artificial polycarbonate and polymethyl methacrylate suspensions. Based on the polymer, the optimal surfactant concentration was 6 wt %. The effect of polymer concentration in solution on the stability and particle size of final polymer suspensions was shown. It was determined that the polymer concentration in the solution should not exceed 10%. When obtaining a highly dispersed suspension during dispersion, a higher concentration causes an increase in the viscosity of emulsions. As a result of a synergistic effect formation, we used mixtures of cationic surfactants (Katamin-AB/Azol-138 and Azol-129/Azol-138) to enhance the stability of the final polymer suspensions. The optimal surfactant ratio was 9:1. The total concentration of the mixture is 10 wt %, based on the polymer. Polymer suspensions were stabilized with each of 2:1 mixtures of cationic surfactants Katamin-AB and Azol-129 withan organosilicon surfactant U-851. The total mixture concentration was 9 wt %, based on the polymer.Conclusions. New methods of producing artificial polycarbonate and polymethyl methacrylate suspensions in the presence of domestically produced cationic surfactants, as well cationicorganosilicon surfactants mixtures, were proposed. The colloidal-chemical properties of the obtained polymer suspensions were considered. It was found that using a 2:1 mixture of cationic and organosilicon surfactants produces polymer suspensions that are stable during production and storage.

The colloid-chemical properties of organosilicon surfactants with different solubility in water were studied. The behavior of organosilicon surfactants of various structures in model systems - Langmuir films at the water-air interface has been studied. The results obtained showed that high stability of polymer suspensions is observed only in the presence of insoluble in water organosilicon surfactants.

The polymerization of styrene in the presence of an organosilicon comb-shaped surfactant, α,ω‑bis(trimethylsiloxy)-oligodimethylmethyl-(10-carboxydecyl)siloxane, is studied. The reaction yields aggregatively stable polystyrene suspensions with a polymer content of up to 50%, a high surface concentration of carboxyl groups, and a particle diameter of up to 2.2 μm. A comparative analysis of the kinetic regularities of polymerization and the properties of polymer suspensions in the presence of the comblike, dimeric, and linear surfactants is carried out.

The colloidal chemical properties of triple block copolymers of polypropylene oxide and polyethylene oxide (pluronics of various structures) were studied in comparison. All of them are shown to be surfactants but differ in interfacial tension, surface activity, surface area occupied in the adsorption layer, and adsorption layer thickness. The kinetic regularities of polymerization of styrene and methyl methacrylate were studied. The particle diameters and their size distribution were determined. Distinctions in the kinetic regularities of polymerization are shown: the shape of the conversion—time curves (for the duration of the initial and stationary stages of polymerization) and the dependences of the diameter on the surfactant concentration and monomer to water volume ratio. In the presence of the water-insoluble pluronics, the mechanism of formation of polymer—monomer particles and interfacial layer on the surface differs from that when using water-soluble surfactants, which makes it possible to distinguish these processes into an independent type of heterophase polymerization.

Abstract—Neutrophil extracellular traps (NET) play an important role in a body’s antimicrobial defense. However, excessive formation leads to various pathological processes in the body. Therefore, a quantitative assessment of the NET content in human whole blood is very important in clinical practice. An approach is proposed allowing the use of polymer microspheres (PMS), the surfaces of which are modified with heparin as sorbents for isolation from whole blood and quantitative determination of NET. To solve this problem, polystyrene microspheres with an average diameter of 140 μm were synthesized, which contain amino groups; covalent immobilization of heparin on their surface was carried out, and a close to linear relationship between the amount of NET and DNA-histone complexes binding to the surface of the synthesized PMS was demonstrated. The data indicate that the approach may be promising both in basic research and clinical practice.

—At present, quite a large number of inducers forming neutrophilic extracellular traps (NET) have been described. Mechanical factors (MF) are of particular importance, since they are constantly acting as neutrophils pass through the microcirculatory system. An adequate choice of therapy for various diseases accompanied by excessive NET formation requires assessment of the ability of a patient’s neutrophils to form NET in response to various inducers. Studying the role of MF in neutrophil activation in patients presents certain difficulties associated with introducing expensive and complex recording systems into laboratory practice. A possible alternative to the existing approaches can be joint incubation of whole blood with hemocompatible polymer microspheres (PMS). To develop this approach, polystyrene microspheres containing quaternary ammonium groups were obtained, on the surface of which hemocompatible aggregates consisting of thiooctadecyl poly-N-vinyl-2-pyrrolidone (PMS nano ) were attached. The data obtained indicate that with incubation of blood samples with PMS nano under gentle stirring, the amount of formed NET is statistically significantly higher than in a stationary incubation mode. This confirms the idea that MF are capable of activating neutrophils and triggering the NET formation process. The proposed approach to assessing the effect of MF on neutrophil activation processes owing to its ease of implementation may find wide application both in biomedical research and clinical laboratories.

The effect of the reactant ratio in the reaction of tetramethyldisiloxane with germanium tetrachloride and diethyl ether on the structure and reactivity of the resulting trichlorogermane–diethyl ether complexes was studied, and the products were reacted with 1,1,3,3-tetramethyl-1,3-divinyldisiloxane. The hydrogermylation of 1,1,3,3-tetramethyl-1,3-divinyldisiloxane with trimethylgermane in the presence of Karstedtʼs catalyst afforded exclusively the corresponding anti-Markovnikov adducts at one and two double bonds of the substrate.

The possible reasons for the occurrence of emulsion polymerization of a monomer simultaneously with suspension polymerization, namely the formation of polymer particles from a highly dispersed fraction of monomer droplets in the initial emulsion and associates of high molecular weight surfactants, are considered. Data on colloidal solubility of monomer in surfactant associates and data on determination of hydrodynamic radii of high molecular weight surfactant associates are presented. The results obtained can be the basis for the choice of surfactants in suspension polymerization, which ensure the minimum contribution of the highly dispersed fraction of monomer droplets to the formation of polymer-monomer particles.

The possible reasons for the occurrence of emulsion polymerization of a monomer simultaneously with suspension polymerization, namely the formation of polymer particles from a highly dispersed fraction of monomer droplets in the initial emulsion and associates of high molecular weight surfactants, are considered. Data on colloidal solubility of monomer in surfactant associates and data on determination of hydrodynamic radii of high molecular weight surfactant associates are presented. The results obtained can be the basis for the choice of surfactants in suspension polymerization, which ensure the minimum contribution of the highly dispersed fraction of monomer droplets to the formation of polymer-monomer particles.