Polyethylene Polyamine Research Articles

TRANSPORT TECHNOLOGIES RELATED TO THE RESTORATION OF SHIP CARGO MECHANISMS WITH THE LATEST MODIFIED EPOXIES

The development of transport technologies today requires not only the creation of bases for the optimal technical use of vehicles, their technical operation, but also their maintenance and repair. One of the main tasks of transport technologies is the search for new promising scientific directions and their implementation in practice, as well as ensuring the effective use of the latest technologies and innovative methods for the construction or repair of water transport facilities. In this respect, the use of epoxy-based polymer composites is promising. They are characterised by improved adhesive and cohesive properties compared to other known oligomers, which determines the wide range of their application in water transport. In order to improve the properties of epoxy-based adhesives, additives of different physical nature are introduced into the epoxy matrix at the initial stage of moulding. This paper investigates the effect of the modifier d-ascorbic acid on the thermal properties of epoxies to obtain a material intended for the restoration of ship loading mechanisms. Based on the dynamics of heat resistance as a function of d-ascorbic acid concentration, the optimum content of the additive in the epoxy compound was determined, which is 1,25...1,50 pts.wt.for 100 pts.wt.of epoxy resin. The introduction of a modifier into the epoxy oligomer provides composites with the highest heat resistance values of all the materials studied. The heat resistance values increase from 341 K (for the epoxy matrix) to 352...354 K. The mechanism of increasing the heat resistance of an epoxy matrix in the presence of a modifier is substantiated, which involves the interaction of epoxy resin with an additive and a hardener as a result of chemical reactions. As a result of the reactions of structure formation of the compound based on epoxy oligomer and modifier in the presence of polyethylene polyamine, mainly strong chemical bonds of C-O, NH2, O-NH2, N=O, N-O-H, C=N type are formed, which largely determine the increase of cohesive strength of the newly formed modified epoxy matrices. It should be noted that it is the cohesive strength of the matrix that determines the thermal resistance of the material at elevated temperatures. It was found that the maximum glass transition temperature (333 K) was observed for the modified material containing d-ascorbic acid at 1,5 pts.wt. At this level of additive, the maximum values of both heat resistance and glass transition temperature were observed compared to the original epoxy matrix (327 K). At this modifier concentration, the cross-linking of the compound forms the most cross-linked structural network of an amorphous polymer with the highest number of chemical bonds.

Research of the influence of adhesive additives on the bond strength between layers of polyvinyl chloride awning materials

To create polyvinyl chloride (PVC) tent materials with high adhesive strength between layers, formulations of plastisols using adhesive additives – ED-20 epoxy resin and polyethylene polyamine (PEPA) crosslinking agent, diisocyanate and perchlorovinyl resin – have been developed. Rheological properties of plastisols containing adhesion additives of different nature have been studied. The effect of adhesion additives on the bond strength between polyester fabric and PVC coating have been investigated.

Construction of a one-stop N-doped negatively charged carbon dot nanoplatform with antibacterial and anti-inflammatory dual activities for wound infection based on biocompatibility

The development of bacterial resistance significantly contributes to the persistence of infections. Although previous studies have highlighted the benefits of metal-doped positive carbon nanodots in managing bacterial wound infections, their mechanism of action is relatively simple and they may pose potential hazards to human cells. Therefore, it is essential to develop a one-stop carbon dot nanoplatform that offers high biocompatibility, antibacterial properties, and anti-inflammatory activities for wound infection management. This study explores the antibacterial efficacy, without detectable resistance, and wound-healing potential of nitrogen-doped (N-doped) negatively charged carbon dots (TPP-CDs). These carbon dots are synthesized using tannic acid (TA), polyethylene polyamine, and polyethylene glycol (PEG) as precursors, with a focus on their biocompatibility. Numerous systematic studies have shown that TPP-CDs can effectively destroy bacterial biofilms and deoxyribonucleic acid (DNA), while also inducing oxidative stress, leading to a potent antimicrobial effect. TPP-CDs also demonstrate the ability to scavenge excess free radicals, promote cellular proliferation, and inhibit inflammatory factors, all of which contribute to improved wound healing. TPP-CDs also demonstrate favorable cell imaging capabilities. These findings suggest that N-doped negatively charged TPP-CDs hold significant potential for treating bacterial infections and offer practical insights for their application in the medical field.

New color changing sorption material for effective removal of heavy metals from wastewater

Relevance. The need to purify water resources from Me(II) cations. Obtaining effective and cheap sorbents is one of the priority areas for water purification for various purposes. Namely, the sorbents, allowing the detection and adsorbing heavy metal cations in drinking or tap water and, at the same time, systematic monitoring of water quality in the environment. Aim. Synthesis of sorption material for effective removal of Me(II) cations from wastewater, study of the main parameters of new sorption material. Objects. Shanghai natural zeolite and its forms modified with polyethylene polyamine, 1,2-pyridylazonaphthol and epoxy resin (ED-20). Methods. Spectrophotometry. Results. A sorbent is proposed based on a combination of a surface layer of polyethylene polyamine, 1,2-pyridylazonaphthol and ED-20 epoxy resin, which is then successfully immobilized on zeolite for adsorption of metal cations Me(II)) from water. The synthesized sorbent makes it possible to diagnose its own efficiency by color changing of the surface after sorption of Me(II) cations. Competing cations of alkali and alkaline earth metals (water hardness salts) do not interfere with the adsorption of Me(II) cations. The maximum sorption capacity was 220 mg/g, which is comparable to other common sorbents. The sorbent also demonstrated the possibility of reuse after 10–12 cycles of desorption and regeneration of the color-forming component 1,2-pyridylazonaphthol. Desorption was carried out using 0.20 M HCl, then the sorbent was ready for being used without significant loss of its characteristics after washing with water. Restoration of the ability to color change was achieved by treating the sorbent in a 10–3 M aqueous solution of 1-(2-pyridylazo)-2-naphthol for 10 minutes.

Increasing the Service Life of Marine Transport Using Heat-Resistant Polymer Nanocomposites.

This paper presents the technological aspects of increasing the thermal stability of polymers, with epoxy binder used to form the polymer materials. Polyethylene polyamine was used to crosslink the epoxy binder. To ensure the thermal stability of the polymer, nanodispersed condensed carbon with a dispersion of 10-16 nm was used. The research into nanocomposites under the influence of elevated temperatures was carried out using the "Thermoscan-2" derivatograph. Complex studies of thermophysical properties were carried out, according to the results of which the optimal content of nanofiller (0.050 pts.wt.) was determined. At the same time, this particular polymer was characterized by the following properties: temperature of the beginning of mass loss-T0 = 624.9 K; final temperature of mass loss-Tf = 718.7 K; relative mass loss-εm = 60.3%. Research into the activation energy of thermal destruction was performed to determine the resistance to the destruction of chemical bonds. It was proved that the maximum value of activation energy (170.1 kJ/mol) is characterized by nanocomposites with a content of nanodispersed condensed carbon of 0.050 pts.wt., which indicates the thermal stability of the polymer.

Protective effect of carbon dots as antioxidants on intestinal inflammation by regulating oxidative stress and gut microbiota in nematodes and mouse models

Inflammatory bowel disease (IBD) is a recurrent chronic colitis disease with increasing incidence and prevalence year by year. The single efficacy and significant side effects of traditional IBD treatment drugs have promoted the flourishing development of new drugs. Inspired by many health benefits of carbon dots (CDs) based nanomedicine in biomedical applications, a metal-free carbon dots (CP-CDs) was synthesized from citric acid and polyethylene polyamine to treat colitis. Oxidative stress tests at the cellular and nematode levels demonstrated CP-CDs have good antioxidant effects, while the toxicity of CP-CDs to cells and nematodes is low. CP-CDs were further applied to dextran sodium sulfate (DSS)-induced colitis in mice models, and it was found that CP-CDs can reduce the disease activity index (DAI) score of colon tissue and restore the intestinal barrier. Further, the anti-colitis mechanisms of CP-CDs were explored, one of which is to regulate intestinal oxidative stress in inflammatory mice, further reducing the expression of inflammatory cytokines, and thus alleviating colitis. Notably, 16S rRNA sequence analysis showed that the abundance of beneficial bacteria (Ligilactobacillus and Enterorhabdus) in the intestinal tract increased, while that of harmful bacteria (unclassified_Clostridia_UCG_014) decreased after CP-CDs treatment, indicating that CP-CDs rebalancing the gut microbiota destroyed by DSS is another important mechanism. In short, these non-toxic carbon dots not only have the potential for multi-factor combined relief of colitis but also offer an alternative therapy medicine for patients suffering from IBD.

Role of the surface layer of epoxy resin

Water pollution threatens human health, and the safe supply of drinking water has been recognized as a problem worldwide. The increasing accumulation of heavy metals in water from various sources has led to the search for effective and environmentally friendly treatment methods and materials for their removal. To impart the necessary characteristics to minerals, in particular to improve sorption properties, one of the methods is modification. Modern technologies using sorbents require qualitatively new sorption materials with increased capacity and high selectivity of action. Epoxy resins are widely used as a base material in the coating field due to their advantages including adsorption properties. In this work, shungite from the Koksu deposit and Shankhanai zeolite were used as natural sorbents for modification. The purpose of this work is to study the interaction of epoxy resin ED-20 with the surface of a natural sorbent through a layer of polyethylene polyamine. Methodology. To study the surface of the prepared samples, methods such as infrared spectroscopy, gravimetry and the temperatureprogrammed desorption method were used. Results and discussion. This article presents the results of IR spectroscopic analysis of natural sorbents shungite and zeolite modified with epoxy resin ED-20 and polyethylene polyamine. The obtained surface epoxy layers were studied for resistance to aqueous environments of varying acidity for 90 days. The acid-base properties of the surface layers of modified sorbents were studied by the method of temperature-programmed ammonia desorption. Conclusion. By modifying shungites and zeolites with polyethylene polyamine, followed by cross-linking them on the surface of a natural mineral with ED-20 epoxy resin, a durable layer of epoxy resin was obtained.

Molecular-mass distribution of alkylphenolformaldehyde oligomers modified by imidazolines

The molecular weight distribution of monoalkyl(C8–C12)phenolformaldehyde oligomers modified with imidazolines based on sunfl ower or corn oil fatty acids and polyamines – diethylenetriamine, triethylenetetraamine, polyethylene polyamines was determined by gel-chromatography. The influence of the component and quantitative composition on the parameters of the number average and weight average molecular weights, as well as on the polydispersity of oligomers, was studied. Regularities have been revealed and assumptions have been made regarding repeating monoalkyl (C8-C12)phenol-formaldehyde fragments in the composition of oligomeric macromolecules.

Effect of Additives on CO2 Adsorption of Polyethylene Polyamine-Loaded MCM-41.

Organic amine-modified mesoporous carriers are considered potential CO2 sorbents, in which the CO2 adsorption performance was limited by the agglomeration and volatility of liquid amines. In this study, four additives of ether compounds were separately coimpregnated with polyethylene polyamine (PEPA) into MCM-41 to prepare the composite chemisorbents for CO2 adsorption. The textural pore properties, surface functional groups and elemental contents of N for MCM-41 before and after functionalization were characterized; the effects of the type and amount of additives, adsorption temperature and influent velocity on CO2 adsorption were investigated; the amine efficiency was calculated; and the adsorption kinetics and regeneration for the optimized sorbent were studied. For 40 wt.% PEPA-loaded MCM-41, the CO2 adsorption capacity and amine efficiency at 60 °C were 1.34 mmol/g and 0.18 mol CO2/mol N, when the influent velocity of the simulated flue gas was 30 mL/min, which reached 1.81 mmol/g and 0.23 mol CO2/mol N after coimpregnating 10 wt.% of 2-propoxyethanol (1E). The maximum adsorption capacity of 2.16 mmol/g appeared when the influent velocity of the simulated flue gas was 20 mL/min. In addition, the additive of 1E improved the regeneration and kinetics of PEPA-loaded MCM-41, and the CO2 adsorption process showed multiple adsorption routes.

Sorption Of Rare Metal Ions by Ionite Based on Diglycidyl Thiourea and Various Amines

The article studies the process of sorption of molybdenum and vanadium ions on anion exchangers obtained on the basis of thiourea, epichlorohydrin and various amines. Various amines (urea, guanidine, melamine, polyethylene polyamine, ethylenediamine, etc.) are used as substances containing ionic groups. The regularities of ion exchange and the main properties of the tested anionites are given, the influence of the pH of the medium and interfering ions in the process of sorption of molybdenum and vanadium ions are studied. For vanadium, the use of empirical partition relations and of an extended Freundlich equation were tested, with promising results. The objective of this paper is to investigate the use of the pH dependent Freundlich model of Gustafsson et al., for describing vanadate(V) sorption to 26 mineral soils (all having less than 12% organic C), and to discuss the possible use of the model for risk assessments. The kinetic curves of the sorption process, the values of the diffusion coefficients for the initial periods of molybdenum sorption are given. In particular, the distribution coefficient of the radiotracers of 99Mo and 131I as homologs of Sg and Ts using the surface modification of chabazite was investigated as liquid-solid system in the present study. The kinetics of molybdenum sorption was carried out under static conditions from an ammonium molybdate solution with a concentration of 1 g/L for molybdenum ions and at pH 4.5–5. Under the same conditions, molybdenum ions are sorbed much faster by the DGT + M anion exchanger in comparison with AN-2F anion exchangers, in which the diffusion coefficient is much lower. The static exchange capacity (SEC) was determined in industrial solutions in the presence of mineral acids (hydrochloric, sulfuric and nitric), usually contained in them. The obtained kinetic equilibrium parameters of the tested anion exchangers were compared with those of industrial polycondensation anion exchangers, such as AN-2F and AN-1.

Functionalizing the surface of polyetherimide (PEI)-based cross-linked separator by introducing the polyamide layer through interfacial polymerization and adding boric acid as electrolyte additive for boosted performance in lithium‑oxygen battery

Lithium‑oxygen battery is a very promising energy storage device for its ultrahigh specific capacity. However, due to the undecomposable insulating oxidation species accumulated on the cathode and the safety issues caused by dendrite penetration, the cycling performance of lithium‑oxygen battery is seriously restricted. Herein, through interfacial polymerization (IP) method, a polyetherimide (PEI)-based separator with dense polyamide thin layer was prepared. And the PEI-based separator is cross-linked with Polyethylene polyamines (PEPA) and undergoes 1,3,5-benzenetricarbonyl chloride (TMC) amidation. According to the SEM result, the obtained polyamide layer is well cross-linked with the PEI-based separator and at the same time it owns a dense micro-pore structure, which ensures a battery structure stability and a good electrochemical performance of the separator. Moreover, the increased IP layer amidated by TMC can not only greatly increase the ionic conductivity of the polyamide/polyetherimide (P/PEI) cross-linked separator to 1.0 mS cm−1, but also significantly decrease the interfacial impedance between the PEI and the electrode. With all these merits, the battery assembled with the representative P/PEI2 separator shows boosted cycling performance of over 90 cycles at a capacity of 1000 mAhg−1. Besides, the electrophilic boric acid was introduced to reduce the interaction between anions and cations, resulting in effectively promoted transport efficiency of lithium ions and the cycling life of the battery can be even prolonged to 108 cycles at a capacity of 1000 mAhg−1.

STUDY OF METAL SORPTION BY COVALENTLY IMMOBILIZED POLYAMPHOLYTES BASED ON AMINO ACIDS

In the presented article, the sorption properties were studied for the first time of polyampholyte, obtained by polycondensation - covalent fixation of ortho-aminobenzoic acid on a matrix of epoxy resin "epoxymol" and polyethylene polyamine. In particular, this polymer was complexed with copper, nickel, zinc, cobalt, and silver ions. The structure of both the resulting polyampholyte itself and its metal complexes with the indicated metals (d-elements) was determined by IR spectroscopy. For the first time, the IR spectra of ligand-polyampholyte complexes with copper, nickel, zinc, cobalt, and silver ions were recorded and studied. These spectra are compared with the spectra of the polyampholyte itself. Scanning electron microscopy (SEM) (photography, elemental analysis) was used to study the microscopic structure of the O-ABA:ED-20:PEPA ligand (ortho-aminobenzoic acid, epoxy resin, polyethylenepolyamine) and its coordination compound with copper ions Cu2+. According to the results of elemental analysis, the gross formulas of the obtained polyampholyte coordination compounds with all coordinated (adsorbed) metals are given. According to the experimental data, obtained as a result of studying the thermal stability of polyampholyte, it was shown that the sorbent is stable up to a temperature of 200 °C. The resulting sorbent is recommended for practical use in the sorption of some d-metal ions from solutions. The dependence of the sorption of some d-metals on the pH of the medium was also studied, and were constructed graphs that describe the dependence of the sorption of metals on pH in the synthesized complexing ligand, showing that the sorption of ions is higher in slightly acidic media.

Thermodynamics of the obtained ion exchanges for the sorption of various ions in environmental wastewaters

This study focuses on investigating the thermodynamic parameters of an ion exchanger synthesized using chlorinated polypropylene with polyethylene polyamines. The ion exchanger, derived from chlorinated polypropylene, demonstrates full compliance with chemical resistance standards. The research involves the examination of isotherms governing the sorption process of Cu(II) and Ni(II) ions by the ion exchanger. These isotherms adhere to the Freundlich model, offering insights into the ion-exchange behavior of the material. Additionally, the study delves into the dynamic exchange capacity and desorption characteristics of the resulting ion exchanger in a granular state. These parameters are crucial for understanding the material's performance in practical applications, shedding light on its ability to efficiently exchange and release metal ions. By comprehensively analyzing the thermodynamic aspects and sorption behavior of the synthesized ion exchanger, this work contributes valuable knowledge to the field of ion exchange materials. The findings offer a basis for further optimization and application of such materials in various industrial processes, particularly in the removal of heavy metal ions from aqueous solutions.

Determination of iron in water by flame atomic absorption spectrometry with sorption preconcentration

Determination and monitoring of pollutants in the natural environment is an urgent task because of their impact on living organisms as a result of numerous anthropogenic impacts. For this reason, a large number of publications are devoted to the development, modification or optimization of analytical methods that can solve these problems. When determining trace elements present in various samples, such as natural and waste water, biological samples and alloy samples, direct determination by various instrumental methods is often impossible due to the matrix effect and rather low concentration of metal ions in the sample. The atomic absorption method is one of the methods widely used for the determination of iron ions, which has such advantages as simplified sample preparation, low probability of contamination and loss of elements, increased analytical productivity, the detection limit of components in the analyzed mixture reduced by several orders of magnitude, and the ability to determine trace amounts of elements in small samples. The aim of the study was to develop a technique for the preliminary concentration of Fe (III) ions in waters of various origins using a sorbent immobilized with sulfosalicylic acid and their further determination by flame atomic absorption spectrometry. Sorbents obtained on the basis of polyacrylonitrile modified with polyethylene polyamine (PPF-1 and PPA-1) with sulfosalicylic acid immobilized on their surface were used for selective sorption of Fe (III) ions. Optimal conditions for the immobilization of sulfosalicylic acid on sorbents and the formation of complexes with Fe (III) ions were studied. The developed sorption-atomic absorption technique provided determination of low concentrations of Fe (III) ions in various waters. The use of PPF-1 as a sorbent with immobilized sulfosalicylic acid for pre-concentration of iron has a number of advantages compared to traditional atomic absorption procedure, i.e., the simplicity, high degree of iron extraction, high sensitivity and selectivity of iron determination, as well as a low cost. The detection limit of iron ions is 0.01 μg/L, Sr does not exceed 0.033.

Structural analysis of petroleum acids in highly acidic crude oil and deacidification using organic amines

Naphthenic acids, polar compounds with carboxylic group, are commonly found in crude oils as product of biodegradation. The presence of NAs in oil can cause corrosion of processing equipment and pipelines and can lead to degradation of crude oil quality. Qilu high acid crude oil was designated for research, from which the acidic fraction was separated by caustic extraction. Elemental analysis, Fourier transform infrared spectroscopy, nuclear magnetic resonance and high-resolution Orbitrap mass spectrometry were used for characterization. The structure of the acidic fraction was verified to be naphthenic acids primarily, and the average molecular formula was obtained. Based on the derivation of the modified B-L method, the average molecular structure was monocycloalkyl benzoic acid with single carboxyl substitution The effects of various depickling solvents and process conditions on deacidification results as well as product were investigated and illustrated with potentiometric titration, UV spectroscopy, zeta potential test and Karl Fischer method. Among the three groups of deacidifiers, inorganic bases represented by sodium hydroxide have the best deacidification efficiency, reaching 83.5 %. But the emulsification caused by sodium naphthenate is severe and the emulsion is stable, making it difficult to achieve oil–water separation. Polyethylene polyamines cause the least emulsification. Moreover, as the number of amino groups in the monomer rises, the number of sites that can be neutralized with petroleum acids increases, and the deacidification rate rises. As result, the most suitable deacidifier for processing is ethanolamine, which can reduce the total acid number of crude oil to 0.47 after three stages of deacidification at 70 °C and a concentration of 10 %.

SYNTHESIS AND PROPERTIES OF BROMINE-CONTAINING BICYCLIC UNSATURATED POLYESTERS

A method for obtaining bromine-containing bicyclic unsaturated polyesters by the interaction of 1,4,5,6,7,7-hexabromobicyclo-[2,2,1]-hept-5-ene-2,3-dicarboxylic acid anhydride, propanetriol and maleic anhydride was developed. It was found that unsaturated polyethers synthesized by a two-step method have a higher molecular weight (3130), density (1.461 g/cm3), viscosity (105 St) and ether number (400 ml KOH/g). It was found that the compositions of epoxy resin ED-20 with unsaturated polyether obtained by method III possess higher tensile strength (90 MPa), higher relative elongation (9%), higher Vicat resistance (2500C) than unmodified epoxy resin. It was shown that in comparison with pure epoxy resin ED-20, its composition with unsaturated polyester synthesized by method I and cured in the presence of polyethylene polyamine (ED-20: unsaturated polyester: polyethylene polyamine), has flame retardant properties, high tensile strength, higher relative elongation and thermal resistance by Vicat. The best results are achieved when the content of unsaturated polyester in the composition is 20%

Removal of hydrogen sulfide by metal-free amine-functionalized mesoporous carbon at room temperature: Effect of amines

The introduction of nitrogen can effectively improve the alkalinity of carbon materials, introduce catalytic sites and active oxygen radicals, thus enhancing the desulfurization ability. However, the study on the effect of amine species and loading amount on the desulfurization properties is very limited. In this study, mesoporous carbon materials with large specific surface area and pore volume were prepared. Different amines were selected as impregnating agents to investigate the performance of amine-functionalized carbon catalysts for hydrogen sulfide (H2S) removal under various operating conditions. The synthesized carbon material has a large specific surface area of 989 m2/g, with an average pore diameter of 12.94 nm. The well-developed pores could not only provide the space for the dispersion of amine, but also facilitate the diffusion of H2S and the storage of sulfur products. Amine increase the alkalinity of carbon material and the reactivity of reaction sites located on the carbon skeleton. The desirable catalytic performance of catalysts impregnated by amines should be the compromise among spatial structure of the amine, the surface chemistry and porosity of catalysts. Among them, the polyethylene polyamine impregnated carbon catalyst with a high ratio of secondary and tertiary amine (80.54 %) showed the best catalytic performance of 1.58 g H2S/g-catalyst at 30 °C due to due to suitable steric hindrance and higher stability in the H2S adsorption–desorption cycle. This work further refines the previously proposed reaction mechanism and provides a possibility for the application of carbon-based catalysts with directional introduction of nitrogen elements by impregnation method in the removal of H2S.

Functional Polymer Nanocomposites with Increased Anticorrosion Properties and Wear Resistance for Water Transport.

Corrosive destruction and hydroabrasive wear is a serious problem in the operation of machine parts and water transport mechanisms. It is promising to develop new composite materials with improved properties to increase the reliability of transport vehicles. In this regard, the use of new polymer-based materials, which are characterized by improved anticorrosion properties and wear resistance, is promising. In this work, therefore, for the formation of multifunctional protective coatings, epoxy dian oligomer brand ED-20, polyethylene polyamine (PEPA) hardener, a mixture of nanodispersed compounds with a dispersion of 30-90 nm, fillers Agocel S-2000 and Waltrop with a dispersion of 8-12 μm, and particles of iron slag with a dispersion of 60-63 μm are used for the formation of multifunctional protective coatings. Using the method of mathematically planning the experiment, the content of additives of different physico-chemical natures in the epoxy binder is optimized to obtain fireproof coatings with improved operational characteristics. A mathematical model is developed for optimizing the content of components in the formation of protective anticorrosion and wear-resistant coatings for means of transport as a result of the complex effect of a mixture of nanodispersed compounds, iron scale, and Waltrop. Based on the mathematical planning of the experiment, new regularities of increasing the corrosion resistance and resources of the means of transport are established through the formation of four different protective coatings, which are tested for resistance to aggressive environments (technical water-CAS No. 7732-18-5, gasoline-CAS No. 64742-82-1, acetone-CAS No. 67-64-1, I-20A lubricant-CAS No. 64742-62-7, sodium solutions-CAS No. 1310-73-2, and sulfuric acid-CAS No. 7664-93-9) and hydroabrasive wear resistances. A study of the change in the permeability index in aggressive environments is additionally carried out, taking into account the rational ratio of dispersive fillers in the epoxy binder, which made it possible to create an effective barrier to the penetration of aggressive water molecules into the base. A decrease in the permeability of protective coatings by 2.0-3.3 times relative to the epoxy matrix is achieved. In addition, the wear resistance of the developed materials under the action of hydroabrasion is investigated. The relative resistance of the CM to the action of hydroabrasion was found by the method of materials and coatings testing on the gas-abrasive wear with a centrifugal accelerator. This method enables one to model the real process of the wear of mechanism parts under the hydroabrasive action. It is shown that the coefficient of the wear resistance of the developed materials is 1.3 times higher than that of the polymer matrix, which indicates the resistance of the composites to the influence of hydroabrasive environment. As a result, modified epoxy composite protective coatings with improved anticorrosion properties and wear resistance under hydroabrasive conditions are developed. It is established that the protective coating filled with particles of a mixture of nanodispersed compounds (30-90 nm), iron scale (60-63 μm), and Waltrop (8-12 μm) has the lowest permeability indicators. The permeability in natural conditions of such a coating during the time t = 300 days of the study is χ = 0.5%, which is 3.6 times less than the similar indicators of the epoxy matrix. It is substantiated that the protective coating filled with particles of a mixture of nanodispersed compounds (30-90 nm), iron scale (60-63 μm), and Agocel S-2000 (8-12 μm) is characterized by the highest indicators of wear resistance. The coefficient of wear resistance under the action of hydroabrasion of such a coating is K = 1.75, which is 1.3 times higher than the similar indicators of the original epoxy matrix.

Anion-Exchange Membrane “Polikon A” Based on Polyester Fiber Fabric (Functionalized by Low-Temperature High-Frequency Plasma) with Oxidized Metal Nanoparticles

An experimental laboratory set of samples of composite heterogeneous anion-exchange membranes was obtained by us for the development of our original method of polycondensation filling. Anion-exchange membranes were prepared on plasma-treated and non-plasma-treated polyester fiber fabrics. The fabric was treated with low-temperature argon plasma at a power of 400 W for 10 min at a pressure of 5 × 10−5 mbar. On the surface and bulk of the polyester fiber, a polyfunctional anionite of mixed basicity was synthesized and formed. The anion-exchange membrane contained secondary and tertiary amino groups and quaternary ammonium groups, which were obtained from polyethylene polyamines and epichlorohydrins. At the stage of the chemical synthesis of the anion matrix, oxidized nanoparticles (~1.5 wt.%) of silicon, nickel, and iron were added to the monomerization composition. The use of ion-plasma processing of fibers in combination with the introduction of oxidized nanoparticles at the synthesis stage makes it possible to influence the speed and depth of the synthesis and curing processes; this changes the formation of the surface morphology and the internal structure of the ion-exchange polymer matrix, as well as the hydrophobic/hydrophilic balance and—as a result—the different operational characteristics of anion-exchange membranes.

Amine-functionalized cotton for the treatment of oily wastewater

Common commercial demulsifiers are typically made from ethylene oxide and propylene oxide. The production process is dangerous and complex, with poor adaptability and high cost. In this work, cotton modified with polyethylene polyamine was utilized as a demulsifier for the treatment of oily wastewater. The chemical structure and morphology of the as-prepared sample (CPN) were characterized by IR spectrum and SEM. The effect of CPN dosage, pH value, and salinity on the demulsification performance of oily wastewater was explored through the bottle tests. The results showed that the light transmittance of separated water was 81.7% and the corresponding deoiling rate was 98.5% when a CPN dosage of 25 mg/L was used at room temperature for 30 min. The interfacial properties were also systematically investigated, and the results indicated that CPN had better interfacial activity and a stronger reduction capability of interfacial tension compared to asphaltenes. The finding initiated and accelerated the demulsification process of oily wastewater. Based on the outstanding performance of this biomass-derived demulsifier, it shows promising potential for application in the treatment of oily wastewater.