Novel frost-resistant polymers based on oligodivinylisoprenediol with a molecular weight 4000 (VID) and its chemically modified analogues (NVID-1, NVID-2, NVID-3) and isophorone diisocyanate have been synthesized for the first time. In order to improve the adhesive and mechanical properties of the NVID-based polymer while maintaining a low glass transition temperature, targeted chemical modification of oligodivinylisoprenediol was carried out for the first time by introducing polar nitro groups into the oligomer chain. As a result, three modified oligodiols (NVID-1, NVID-2, NVID-3) were obtained with a nitro group content in the range from 0.54

The goal of present work is to create a polymer base for compounds, binders for materials with different fillers and adhesives. The article presents the results of studies of the physical and mechanical characteristics of urethane-containing elastomers based on epoxy urethane oligomers. The reaction proceeded in two stages and included the formation of oligodiisocyanate. Based on them, elastomers with urethane-hydroxyl hard segments were synthesized. Methyl nadic anhydride and an oligodiendiol with terminal carboxyl groups were used as hardeners. The deformation-strength properties of elastomers, as well as the strength of the adhesive joints for aluminum and steel, were studied. Using an oligomer with carboxyl groups as a hardener lowers the glass transition temperature of elastomers and improves their deformation characteristics. The glass transition temperature of the samples was determined using a differential scanning calorimeter. The physical and mechanical tensile characteristics of the obtained materials were determined on a universal testing machine. Elastomers cured with an oligomer containing carboxyl groups can be used as a polymer base for compounds and binders for materials with different kinds of fillers due to their low modulus and high deformation properties. Elastomers cured with methyl nadic anhydride may find use as adhesives.

Prussian Blue, a blue coordination polymer, emerges as a promising candidate in the realm of biomedicine. Its nanoparticles, known as catalytic labels or nanozymes, exhibit remarkable peroxidase-like properties and serve as effective antioxidants. Unsurprisingly, the demand for synthesizing Prussian Blue nanoparticles with customizable sizes is on the rise. In this study, we unveil a novel approach to synthesizing Prussian Blue nanoparticles. In this work, the synthesis of Prussian Blue nanoparticles by reducing an equimolar mixture of FeCl3 and K3[Fe(CN)6] with hydrogen peroxide in different water-alcohol mixtures was demonstrated for the first time. Alcohols with a lower dielectric constant (propanol-1, isopropyl alcohol, and tert-butanol) contribute to an increase in nanoparticle size, particularly at mole fractions of 0.02-0.05 and beyond. Conversely, alcohols with a higher dielectric constant (ethanol, methanol, ethylene glycol, and propylene glycol, excluding glycerol) demonstrate the ability to decrease nanoparticle size at mole fractions of 0.2-0.26 and higher. Building upon these findings, we present a scalable and reproducible method for preparing small Prussian Blue nanoparticles, measuring 30-40 nm, with enhanced peroxidase-like activity using 79.2% ethylene glycol as a solvent. The proposed mechanism behind the effect of ethylene glycol involves the limitation of both growth and secondary aggregation of Prussian Blue nanoparticles. These synthesized nanoparticles prove their efficiency as catalytic labels in a model vertical flow immunoassay designed to detect antibodies against SARS-CoV-2.

In this work, new polymers with a shape memory effect for self-healing coatings based on oligomers with terminal epoxy groups, synthesized from oligotetramethylene oxide dioles of various molecular weights, were developed. For this purpose, a simple and efficient method for the synthesis of oligoetherdiamines with a high yield of the product, close to 94%, was developed. Oligodiol was treated with acrylic acid in the presence of a catalyst, followed by the reaction of the reaction product with aminoethylpiperazine. This synthetic route can easily be upscaled. The resulting products can be used as hardeners for oligomers with terminal epoxy groups synthesized from cyclic and cycloaliphatic diisocyanates. The effect of the molecular weight of newly synthesized diamines on the thermal and mechanical properties of urethane-containing polymers has been studied. Elastomers synthesized from isophorone diisocyanate showed excellent shape fixity and shape recovery ratios of >95% and >94%, respectively.

Point-of-care tests play an important role in serological diagnostics of infectious diseases and post-vaccination immunity monitoring, including in COVID-19. Currently, lateral flow tests dominate in this area and show good analytical performance. However, studies to improve the effectiveness of such tests remain important. In comparison with lateral flow tests, vertical flow immunoassays allow for a reduction in assay duration and the influence of the hook effect. Additionally, the use of carbon black nanoparticles (CNPs) as a color label can provide a lower detection limit (LOD) compared to conventional colloidal gold. Therefore, we have developed a vertical flow immunoassay for the detection of IgG against SARS-CoV-2 spike protein in human serum samples by applying a conjugate of CNPs with anti-human IgG mouse monoclonal antibodies (CNP@MAb). The vertical flow assay device consists of a plastic cassette with a hole on its top containing a nitrocellulose membrane coated with spike protein and an absorbent pad. The serum sample, washing buffer, and CNP@MAb flow vertically through the nitrocellulose membrane and absorbent pads, reducing assay time and simplifying the procedure. In positive samples, the interaction of CNP@MAb with anti-spike antibodies leads to the appearance of black spots, which can be visually detected. The developed method allows for rapid visual detection (5–7 min) of IgG vs. spike protein, with a LOD of 7.81 BAU/mL. It has been shown that an untrained operator can perform the assay and visually evaluate its results. Thus, the presented assay can be used in the further development of test systems for the serological diagnostics of COVID-19 or post-vaccination immunity monitoring.

Contemporary immunoassays commonly used in clinical diagnostics mostly utilize enzymes, such as horseradish peroxidase, for signal generation. Numerous research is dedicated to the development of artificial peroxidase-mimicking catalysts with lower cost, high activity, better operational stability, and tunable properties. Herein we synthesized hemin-loaded bovine serum albumin (BSA) nanoparticles and applied them as catalytic labels (nanozymes) in colorimetric immunoassay of anti-tetanus antibodies. Hemin is a key part of the peroxidase catalytic center, possessing peroxidase like-activity. Albumin nanoparticles were loaded with multiple hemin molecules and decorated with Streptococcal protein G. Resulting nanozymes possessed good colloidal stability and allowed for antibody detection in blood serum. The sensitivity of antibody detection was sufficient for the assessment of post-vaccination immunity.

The thermal oxidation of coal tar and coking products of oxidized pitch is investigated. An isothermal process of thermal oxidation is considered, as well as a process with steady increase in the temperature. The oxidized pitch is subjected to technical analysis (determining the fractional composition, the softening temperature Tso, and the yield of volatiles), elemental analysis, and thermal analysis. The pitch is carbonized in standard conditions; the degree of swelling is determined on heating. The coke produced is optically analyzed. After treatment at 900–1600°C, the porous structure of the quenched coke is studied. The results confirm that isotropic coke may be obtained from coal tar; optimal production conditions are determined. The isotropic coke obtained has a highly uniform microstructure and is resistant to cracking at high temperatures.

The isotropic coke used as filler in the production of structural graphite must have invariant characteristics—in particular, its microstructure. Complete elimination of anisotropic structural elements (of length >10 μm) in the coke structure is difficult. In the present work, a new approach is considered for reducing the content of regions with microstructure score >2 (according to State Standard GOST 26132) in coke: forced removal of distillates by inert-gas injection in the reaction mixture.

The influence of the molecular weight of oligoamine, oligoether, and the type of diisocyanate on the physical and mechanical properties of elastomers with urethane hydroxyl hard segments was studied. For this purpose, oligoetherdiamines with molecular weights ~1008 and ~1400 g mol−1 were synthesized by a three-stage method. Epoxyurethane oligomers were synthesized according to a two-step route with an oligodiisocyanate as an intermediate product. A series of 12 elastomers with controlled crystallinity were synthesized from these elastomers and amines. The deformation and strength properties of the elastomers were studied.

Новые технологии, Химическая промышленность, Химическая технология, Научные журналы, Защита от коррозии, Технология металлов, Свойства материалов, Технические журналы, Наука и технологии, Справочная литература, Научные разработки

Prussian blue nanozymes exhibit peroxidase-like catalytic activity and are therefore considered a stable and inexpensive alternative to natural peroxidases in the enzyme-linked immunosorbent assay (ELISA). In this work, we propose a robust method of Prussian blue nanozyme functionalization, which relies on the entrapment of nanozymes into albumin nanoparticles. The principle of the method is the addition of ethanol to a solution that contains albumin and nanozymes. At a high ethanol concentration solubility of albumin decreases, resulting in the formation of albumin nanoparticles loaded with nanozymes. The hydrodynamic diameter of nanoparticles was between 120 and 230 nm and depended on the nanozyme-to-BSA ratio. Encapsulation efficiency of nanozymes reached 96–99% and up to 190 μg of nanozymes were loaded per 1 mg of nanoparticles. Nanoparticles were stable at pH 5.5–7.5 and upon long-term storage in deionized water. Excellent reproducibility of the synthesis procedure was confirmed by the preparation of three individual batches of Prussian-blue-loaded BSA nanoparticles with almost identical properties. Nanoparticles were functionalized with monoclonal antibodies using glutaraldehyde cross-linking. The resulting conjugates were applied as labels in an ELISA-like assay of tumor marker prostate-specific antigen (PSA). The lower limit of detection was below 1 ng/mL, which enables measurement of PSA in the range of clinically relevant concentrations.

The characteristics of synthetic and industrial coal-tar pitch samples are investigated. The characteristics of the corresponding pitch cokes are compared. Three materials are considered: synthetic low-temperature pitch based on coal-tar distillate; and medium and high-temperature industrial coal-tar pitches from different Russian producers. The influence of the pitch composition on the properties of the pitch coke is determined.

The Foreign Object Damage problem is considered as the damage tolerance statement for consecutive loading tests, which include the shock-wave loading (by explosive generator) of massive planar targets (aluminum alloy AlMg6) to provide a billet for the specimen machining with controlled damage that is the analogous material of the fan blades subjected to high-speed collision with solid particles. These samples were used to perform high cycle fatigue and very high cycle fatigue tests with the ultrasonic testing machine, which allows fatigue loading for 108–1010 cycles with an amplitude of up to several tens of micrometers and a frequency of 20 kHz. It is shown that the fatigue strength of AlMg6 alloy specimens pre-loaded by shock in the 109 cycle regime reduces by 24%. The fatigue damage-failure transition and crack initiation were studied by the amplitude–frequency analysis of higher harmonics associated with the influence of defects on the effective elastic properties. The structural study of the fracture surface for the specimens after consecutive loading was conducted using the profilometry data to identify the roughness scale invariants induced by defects for corresponding areas responsible for the staging of fatigue damage-failure transition. The scale invariants and corresponding lengths were used for the formulation of the generalized Paris law for the crack advance in the damaged material.

For the first time, ZnO/C composites were synthesized using zinc glycerolate as a precursor through one-step calcination under a nitrogen atmosphere. The effect of the heat treatment conditions on the structure, composition, morphology as well as on the electrochemical properties regarding application in lithium-ion batteries are investigated. The products obtained by calcination of the precursor in nitrogen at 400—800 °C consist of zinc oxide nanoparticles and amorphous carbon that is in-situ generated from organic components of the glycerolate precursor. When used as anode material for lithium-ion batteries, the as-prepared ZnO/C composite synthesized at a calcination temperature of 700 °C delivers initial discharge and charge capacities of 1061 and 671 mAh g −1 at a current rate of 100 mA g −1 and hence 1.5 times more than bare ZnO, which reaches only 749/439 mAh g −1 . The native carbon improves the conductivity, allowing efficient electronic conductivity and Li-ion diffusion. By means of ex-situ XRD studies a two-step storage mechanism is proven.

A nuclear magnetic resonance (NMR) immunoassay based on the application of carbon-coated iron nanoparticles conjugated with recognition molecules was designed. The principle of the assay is that ELISA plates are coated with a capture element, and then an analyte is added and detected by conjugating the magnetic nanoparticles with recognition molecules. Afterwards, the elution solution (0.1-M sodium hydroxide) is added to displace the magnetic nanoparticles from the well surfaces into the solution. The detached magnetic nanoparticles reduce transverse relaxation time (T2) values of protons from the surrounding solution. A portable NMR relaxometer is used to measure the T2. Magnetic nanoparticles conjugated with streptavidin, monoclonal antibodies, and protein G were applied for the detection of biotinylated albumin, prostate-specific antigen, and IgG specific to tetanus toxoid (TT). The limit of detection of anti-TT IgG was 0.08–0.12 mIU/mL. The reproducibility of the assay was within the acceptable range (CV < 7.4%). The key novelty of the immunoassay is that the displacement of the nanoparticles from the solid support by the elution solution allows the advantages of the solid phase assay to be combined with the sensitive detection of the T2 changes in a volume of liquid.

Abstract A method for the synthesis of oligotetramethylene oxides with terminal amino groups is presented. Its use as a hardener for urethane-containing oligomers has been demonstrated. The diamines were synthesized by a two-stage method based on oligotetramethylene oxide diol. The compounds can be used for the production of non-toxic, biocompatible and biodegradable segmented urethane-containing elastomers. The oligotetramethylene oxide diol with an average molecular mass of 1008 was chosen as a typical precursor component. Its dibromide was formed using a quasi-phosphonium reagent in various solvents. The corresponding amine was obtained by high-pressure amination. The compounds have been identified by 1H and 13C NMR spectroscopy, IR spectroscopy, and elemental analysis.

Copolymers of N,N-diallyl-Nʹ-acetylhydrazine and N,N-diallyl-Nʹ-benzoylhydrazine with acrylic acid, acrylonitrile, and acrylamide were synthesized by radical copolymerization in the presence of a radical initiator azobisisobutyronitrile. The borohydride method was used to produce new polymer nanocomposites containing silver nanoparticles 31–55 nm in size, stabilized by synthesized copolymers of N,N-diallyl-Nʹ-acylhydrazines. The presence of heteroatomic fragments and functional groups (carboxyl, amide, nitrile, acetyl, benzoyl, hydrazine) in the polymer chain promotes specific interaction with silver particles, regulating the particle size at the nanoscale and ensuring their uniform distribution in the polymer matrix. Structural features of nanocomposites were investigated using UV, IR, NMR spectroscopy and scanning electron microscopy. The produced nanocomposites exhibit cytotoxic activity against MS melanoma cells and RD rhabdomyosarcoma cells and are promising as new-generation drugs intended for the treatment of cancerous tumors.

The introduction of small amounts of calcium stearate and molybdenum disulfide into polyurethane ureas based on a oligoether of polyoxytetramethylenediol with a molecular weight M~1000 does not lead to a significant change in the abrasive wear mechanism of the polymer material. The concentration dependence of the wear degree on the filler content has an extreme character, which is associated with the different direction of the filler effect on the cohesive and frictional properties of the studied material.

A new bifunctional epoxy resin was synthesized by the reaction of replacing the hydrogen atom of amino groups from 4,4-diaminodiphenylmethane and epichlorohydrin taken in a double excess in dichloroethane. In order to remove HCl formed during the synthesis, which can interact with the initial diamine, as well as with the oxirane rings of both epichlohydrin and the synthesized product, an excess of potassium carbonate was introduced into the reaction mixture. The structure of the synthesized epoxy resin - 4,4′-methylenebis (N- (oxiran-2-ylmethyl) aniline) was characterized and proved by the methods of FTIR spectroscopy, nuclear magnetic resonance and elemental analysis. The kinetic parameters of the synthesized resin were characterized by differential scanning calorimetry. Using the Kissinger method, the activation energy of the self-curing reaction was calculated, the value of which was 1.139 kJ / mol. Such a low activation energy of epoxy resin allows to cure at low temperatures, but shortens the storage time. Two curing modes were studied: 1 mode - 10 hours at 150 ° C, 2 step mode - 10 hours at 150 ° C + 3 hours of postcuring at 180 ° C.