Anticorrosion Effect Research Articles

Synthesis, Characterization and Evaluation of Some Meldrum's Acid Derivatives as Lubricant Additives

Aminomethylene Meldrum’s acid derivatives were synthesized by a three-component, one-pot reaction of Meldrum's acid with triethyl orthoformate and different aromatic amines. The prepared compounds were characterized using Fourier transform infrared (FT-IR), nuclear magnetic resonance (1H NMR and 13C NMR) and evaluated as anti-corrosion and anti-rust additives by blending with base lubricating oil, according to the American Society of Testing and Materials (ASTM-D130 and ASTM-D665). The blends of the synthesized compounds with the base lubricating oil showed better anti-rust and anti-corrosion effects than the base oil Blank).

Dispersive adsorption and anticorrosion properties of natural capsaicin on Q235 steel in mixed H2SO4 and NaCl environment: Characterization, experimental and theoretical studies

Although traditional corrosion inhibitors have demonstrated immense relevance in metal protection for many years now, issues relating to their moderate to high toxicities, non-biodegradability, and cost-effectiveness have persisted. For these reasons, bio-based corrosion inhibitors are gathering significant research attention and have shown great potentials in the corrosion suppression of metals while being relatively cheap and eco-friendly. This study focuses on the anticorrosion and adsorption properties of natural capsaicin isolated from Capsicum annuum L. as a bio-based corrosion inhibitor for Q235 steel in a mixed acid and chloride system (0.25 M H2SO4 + 0.5 M NaCl). FTIR and NMR techniques afforded the characterization and identification of the phytocompound. Electrochemical and gravimetric measurements were employed for anticorrosion evaluations. 3D surface profilometer, SEM, and water contact angle examinations provided adsorption proof for capsaicin on steel surface. XPS provided insights into the corrosion suppression mechanism of capsaicin. Computational techniques allowed the description of the adsorption characteristics, molecular interactions, molecular orientations and binding energies of capsaicin on steel substrate. Having a maximum inhibition performance of 94.8% at 298 K, capsaicin was classified as a functional mixed-type corrosion inhibitor that is reliant on concentration and surrounding temperature for its effectiveness. While also validating the results from water contact angle measurements, 3D profiling, and SEM, XPS results disclosed that the interactions of capsaicin with steel surface leading to its adsorption and anticorrosion effect involved both physisorption and chemisorption processes, and this was in perfect correlation with the Langmuir monolayer adsorption model.

The study on corrosion inhibition effect of 2-Phenylbenzimidazole for X70 steel in HCl solution at 308 K

The inhibition behavior of X70 steel with different concentrations of 2-Phenylbenzimidazole in 1 M HCl solution at 308 K was evaluated through electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP) curves and scanning electron microscopy (SEM). It was found that the inhibition efficiency increased with increasing of 2-Phenylbenzimidazole concentration, and the best inhibition efficiency was achieved at 5 mM. Analysis of the polarization curves showed that 2-Phenylbenzimidazole belonged to mixed type inhibitor, inhibiting concurrently cathode and anode, and the inhibition effect was more significant for cathode. Moreover, the adsorption isotherm study showed that the adsorption of 2-Phenylbenzimidazole inhibitors on the surface of X70 steel followed the Langmuir adsorption model, and the calculation of the standard free energy of adsorption (ΔG0ads) indicated the presence of both physical and chemical adsorption. Furthermore, molecular dynamics (MD) simulations were applied to display the mechanism of the strong anticorrosion effect of 2-Phenylbenzimidazole molecules.

Applications of Polyaniline–Alkaline Copper Carbonate Composites for Anti-Bio-Attachment of Concrete in Marine Environments

This study proposed the use of polyaniline–alkaline copper carbonate composites as anti-corrosion and anti-biofouling concrete additives and established a set of high-dispersion preparation methods for this composite additive. The effects of polyaniline–alkaline copper carbonate composites in concrete were investigated in marine environments via the preparation of concrete specimens, actual sea suspension experiments, concrete mechanical property tests, and biological attachment avoidance tests. The experimental results showed that (1) the yield of the chemical reactions leading to the preparation of the composite was above 96.46% with a good output. The composite was hydrophilic. The addition of ethylene carbonate as a surfactant and the mixing of the composite into the concrete in a suspension form enabled uniform dispersion of the composite. (2) In the sea waters of Zhoushan, China, bio-attachment was mainly dominated by barnacles and sea anemones. Polyaniline–alkaline copper carbonate composites had good anti-bio-attachment properties and could significantly reduce the amount of bio-attachment in concrete. (3) When the additive content was less than 0.20% of the concrete mass, it did not negatively affect the mechanical properties of the concrete specimens and exerted anti-corrosion and anti-biofouling effects. This reduced the strength loss of concrete and increased the service life of the concrete specimens in the ocean. To ensure the best application effect of the compound in concrete, the recommended content of the compound is 0.05–0.15% of the concrete mass.

Improved Antifouling Ability for Double‐Network Hydrogel Coatings with Excellent Elastic and Toughness under Marine Tidal Environment

The marine coating in the tidal zone is crucial to restoring its protective function in the case of coating defects, mainly due to the structural damage of the coating by the alternation of wet and dry in the tidal zone and the surface damage of the coating by the impact of sand and gravel. Hydrophilic materials such as hydrogel transformed the tidal zone into an entire immersion zone. Due to the complexation of copper, the fouling problem can be effectively reduced. The coating (AAm/Alginate‐Ca/Cu‐BTA) has excellent mechanical properties (modulus: 200 kPa, toughness 128 J m−2) and significant adhesion (138 J m−2). Otherwise, herein, simultaneously mechanical tests of hydrogels at different temperatures and excellent mechanical properties (modulus: 160 kPa, toughness 100 J m−2) after 7 days of use in alternating dry and wet environments every 6 h are shown. It's proved that the coating has an excellent antifouling and anticorrosion effect. Meanwhile, theoretical study reveals the nature of the weak mechanical properties of hydrogel materials at low temperatures. This work provides an effective strategy for preparing hydrogel coatings with excellent mechanical properties and marine anticorrosion and antifouling. It also proves that hydrogels have broad application prospects in marine tidal zone by excellent water retention performance.

Synergistic Effects of 1-Octyl-3-Methylimidazolium Hexafluorophosphate and Cellulose Nanocrystals on Improving Polyacrylate Waterborne Anti-Corrosion Coatings

In this study, three copolymers of poly(methyl methacrylate) and poly(butyl acrylate) (PMMA-co-PBA) latex containing 1-octyl-3 methylimidazolium hexafluorophosphate (C8mimPF6), cellulose nanocrystals (CNCs), and C8mimPF6-CNCs were successfully synthesized through mini emulsion polymerization. These novel composites were each coated on mild steel panels and tested for their anti-corrosion performance by immersion of the coated samples in 3.5 wt% sodium chloride (NaCl) solution over a certain period. The synergistic anti-corrosion effects of the C8mimPF6-CNCs sample led to the highest coating resistance, charge transfer resistance, and corrosion inhibition efficiency and the lowest diffusion coefficient and corrosion rate. The proposed synergistic mechanism revealed that CNCs enhanced the barrier effect of the coating while C8mimPF6 inhibited corrosion when released.

Anti-corrosive non-aqueous DBSA/MEA lamellar liquid crystal lubrication system

HypothesisSince lamellar liquid crystals (LLCS) could be used for lubrication, many LLCS systems have been constructed to improve lubrication performance. However, most studies focused on the LLCS of the water system, and its corrosiveness brought some limitations to its application. Therefore, it is necessary to construct a non-aqueous LLCS system with good lubrication and anti-corrosion properties to improve its applicability. ExperimentsAnionic surfactant dodecyl benzene sulfonic acid (DBSA) was used to construct non-aqueous LLCS in different solvents, including monoethanolamine (MEA) and diethanolamine (DEA). DBSA/H2O LLCS system was constructed for comparison. The LLCS was characterized by polarizing microscope (POM), small-angle X-ray scattering (SAXS), and rheology. Its microstructure was discussed. Meanwhile, we evaluated the lubrication and anti-corrosion performance of LLCS. Its lubrication mechanism was explained through tribology tests and X-ray photoelectron spectrometer (XPS) analysis of the wear scar surface. Its anti-corrosion mechanism was investigated by using the weightlessness method, electrochemical test method, and quantum chemical theoretical calculations. FindingsThe DBSA/MEA non-aqueous LLCS system showed better lubrication performance than DBSA/DEA and DBSA/H2O LLCS. It can adsorb on the surface of the friction pair to form a lubrication friction film, which plays a better role in reducing friction and wear. The DBSA/MEA LLCS is less corrosive to metals because it can effectively isolate oxygen and water in the air between friction pairs. Furthermore, the lone pair electrons in the 2p orbital of the N atom in the MEA molecule could coordinate with the 3d empty orbital of the Fe atom, forming a protective film on the metal surface, which plays a good anti-corrosion effect. This work not only enriched the study of non-aqueous LLCS but also expanded its potential applications in the field of lubrication.

Construction of a nano-micro nacre-inspired 2D-MoS2-MOF-glutamate carrier toward designing a high-performance smart epoxy composite

For the first time, dual-functional pH-sensitive and water-barrier epoxy coating was prepared by introducing the monosodium-glutamate molecules into the ZIF-8@MS nano-hybrid. By performing the FTIR, XRD, BET, and FE-SEM investigations the successful production of ZIF-8 particles on the MS surface was proved. Based on the mesoporous nature of the ZIF-8 particles, they were utilized as a pH-responsive carrier to encapsulate the glutamate molecules and Zn2+-ions as effective corrosion inhibitors. Owing to the pH-responsive behavior of ZIF-8@MS, the corrosion resistance of the bare steel (Z 0.01 Hz = 7466 ohm.cm2) was improved in a saline solution containing particle extract. The ZIF-8@MS-filled epoxy resin provided excellent corrosion resistance after 21 days of exposure due to the excellent barrier impact of 2D MS sheets and the smart release of corrosion inhibitors. The self-healing capability of the epoxy coatings filled with glutamate and Zn2+ loaded ZIF-8@MS was demonstrated by FE-SEM, EIS, and salt spray tests. The synergistic anti-corrosion effect of the combined inhibitors was shown by EIS outcomes. The results have revealed a considerable improvement in the storage modulus, Tg, crosslink density, and tensile strength, which verified the effective duty of ZIF-8@MS particles in the epoxy film’s mechanical properties.

Influence of Alternating Current Density on the Mechanical Behavior and Microstructure of PEO-Coated 7075 Aluminum Alloy

The objective of the study was to investigate the characteristics of coatings formed on 7075 Al alloy using a plasma electrolytic oxidation (PEO) method in silicate electrolytes under alternating current conditions. The properties of the coatings were evaluated based on the current density applied during the experimental process. To analyze the samples, the surface and cross-sectional images of the coatings were observed using scanning electron microscopy. The results showed that the PEO coatings were between 25–102 µm in thickness, and the thickness was found to be dependent on the applied current density. The hardness values of the PEO coatings were found to be significantly, approximately three times, higher than the uncoated alloy. Wear analysis revealed that the PEO coatings formed under current densities of 8.8 A/dm2 and 17.8 A/dm2 exhibited the best wear resistance among all the coatings. In addition, the PEO coatings also displayed good corrosion resistance, with the resistance of the coatings formed under the current densities of 13.5 A/dm2 and 17.8 A/dm2 being significantly improved compared to that of the bare Al alloy. The most effective anticorrosion PEO coating was found to be the one formed under a current density of 17.8 A/dm2. The wear depths of the PEO coatings formed under current densities of 8.8 A/dm2 and 17.8 A/dm2 were low, resulting in high wear resistance. Among all the PEO coatings, the coating formed under a current density of 17.8 A/dm2 showed the best overall anticorrosion and mechanical properties. Overall, the study highlights the potential of PEO coatings in significantly improving the corrosion and wear resistance of 7075 Al alloy. The results of the study provide useful information for the selection of current density for the PEO coating process on 7075 Al alloy to achieve desired properties.

The Effect of Atmospheric Chloride Ions on the Corrosion Fatigue of Metal Wire Clips in Power Grids

Corrosion fatigue is an important factor that limits the life of grid materials including wire clips. In order to study the effect of corrosion fatigue and to select suitable grid steels, this paper focuses on the corrosion fatigue properties of Q235 carbon steel, Q235 galvanized steel, and 316L stainless steel in the corrosive environments of air, 2wt% NaCl, 5wt% NaCl, and 8wt% NaCl. Through the fatigue test in the corrosive environment, and the surface morphology scanning and microstructure observation of the fracture, the following conclusions are drawn: the three materials are more susceptible to corrosion fatigue in the Cl− environment, and the higher the Cl− concentration, the greater the likelihood of fracture caused by corrosion fatigue for these three materials. By analyzing the surface roughness, dimples, and cracks in the microstructure, it is found that 316L stainless steel is highly sensitive to Cl− corrosion under cyclic stress, and Q235 galvanized steel is more resistant to Cl−. By plotting the stress fatigue life curve of Q235 galvanized steel, it is found that the corrosion fatigue life decreases as the Cl− concentration increases. For wire clips in areas with severe Cl− pollution, Q235 galvanized steel should be selected to achieve the best anti-corrosion fatigue effect; at the same time, the original parts should be repaired or replaced in a timely manner based on the predicted corrosion fatigue life.

Theoretical and electrochemical evaluation of tetra-cationic surfactant as corrosion inhibitor for carbon steel in 1 M HCl

Recently, scientist study the role of surfactants for carbon steel corrosion protection. In the present study, newly tetra-cationic surfactant (CS4: 1,N1'-(ethane–1,2-diyl) bis (N1, N2—didodecyl–N2–(2- (((E)-3-hydroxy-4-methoxy-benzylidene)amino)ethyl)ethane-1,2-diaminium) chloride) based on Schiff-base compound(5,5'-((1E,17E)-2,5,8,11,14,17-hexaazaoctadeca-1,17-diene-1,18-diyl)bis(2-methoxyphenol) was synthesised, purified and characterized using FTIR and 1HNMR spectroscopy. The synthesized Tetra-cationic surfactant (CS4) was evaluated as anti-corrosion for carbon steel (CS-metal) in aggressive 1 M HCl using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques (PDP). CS4 compound had a good surface-active property by reducing the surface tension as a result to the hydrophobic chains role. The prepared CS4 behaved as hybrid inhibitor (mixed-type) by blocking the anodic and cathodic sites. CS4 exhibited good inhibition efficiency reached 95.69%. The surface morphology of CS-metal was studied using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS)confirming the anti-corrosive effect of CS4 compound returned into the adsorption process of CS4 molecules over CS-metal which obeyed Langmuir adsorption isotherm. The inhibitive effect of CS4 was supported by theoretical quantum chemical studies using the density functional theory (DFT), Monte Carlo (MC) and Molecular Dynamic (MD) simulation.

Enhancing corrosion resistance of magnesium alloys via combining green chicory extracts and metal cations as organic-inorganic composite inhibitor

Organic inhibitors provide advantages for corrosion protection through formation of chelation layers. However, individual inhibitors have weak inhibition efficiency when they are exposed to neutral media containing chloride ions. In this study, corrosion resistance of Mg alloy AZ91D is synergistically enhanced by combining green chicory (CA) extracts with metal cations (Ca2+, Fe3+, Fe2+, and Ni2+). The Mg(OH)2 and MgO corrosion products are porous in the early stages of immersion. The main organic compounds in CA including caffeic acid (Caf) and chicoric acid (Chi), which combine with inorganic cations via chelation reaction, are adsorbed on the corroded area. The large Bader charge and adsorption energies of Chi-Calcium-Chi (CaChi) complexes determined through density functional theory calculations suggest that CaChi interacts strongly with inorganic cations. The combined organic–inorganic inhibitors can therefore be absorbed firmly on the Mg substrate to form an active inhibitory layer. Among the various investigated CA-cation mixtures, CA-Ca2+ exhibited the highest anti-corrosion effect after immersion for 120 h and a corrosion current density (icorr), corrosion potential (Ecorr), and inhibition efficiency (η) of 0.09 ± 0.03 μA·cm−2, –0.87 ± 0.03 V (vs. SCE), and 92%, respectively. This work provides an effective approach for corrosion protection through combination of organic and inorganic inhibitors.

Machine visual technology based steel corrosion evaluation and analysis of power transformation lines: A Zhejiang power grid case study

It can be seen that the corrosion failure of transmission and transformation equipment has increasingly restricted the safe operation of the Zhejiang power grid bottleneck problem. If effective anticorrosion measures are not taken promptly, transmission and transformation equipment serving in various sophisticated atmospheric environments will suffer serious corrosion damage in a relatively short period, which endangers the safe usage of transmission and transformation equipment and the security of grid operation. In this article, through the establishment of transmission and transformation steel components corrosion fracture mechanics model, a standard corrosion spectrum grading software based on DeepLabV3+ image segmentation technology is developed to determine the quantitative assessment method of corrosion damage and assess the corrosion status with safety degree of transmission and transformation equipment. According to the assessment results, the operation and maintenance units are guided to adopt differentiated corrosion maintenance and replacement strategies, so as to reduce corrosion safety hazards and reduce safety accidents and economic losses caused by corrosion, which is of great significance for the safe operation of power grids.

A comprehensive review on the nature and synthetic organic compounds as corrosion inhibitors

Although corrosion is an inevitable part of daily life, it is always kept under control due to its technical, financial, and aesthetic significance. Erosion is a gradual phenomenon stimulated by anxiety about energy. Defense against corrosive environments on metals is inhibition. One of the most common and financially viable methods of preventing corrosion in metallic materials is the use of corrosion inhibitors (CIs). One of the five ways to prevent material corrosion, along with material selection, design, cathodic protection, and coating, is to use organic CIs. Particles with an unoccupied orbit on a metal substrate depend on adsorption values on the steel surface through the interactions of heteroatoms (N, O2, P, S), heterocyclic and aromatic rings, and conjugated double bonds. Through these interactions, molecules are attracted to the metal surface, where they bind and form an inhibitory barrier. This reduces the metal's corrosion rates as well as improves inhibition effectiveness. This review included a presentation of the CI compound's history before moving on to a discussion of how inhibition efficiency is affected by structure, substitution, heteroatoms, and molecular chain length. Weight loss (WL), electrochemical impedance spectroscopy (EIS), and dynamic active polarization techniques are used in a comparative investigation of the inhibitory performance of corrosion-inhibited compounds. Adsorption isothermal concepts and blocking processes. This paper discusses corrosion processes and scaling, various experimental corrosion techniques, the relationship between anticorrosion structure and effectiveness, and the process of novel inhibitors.

Synthesis of an eco-inspired anticorrosive composite for mild steel applications.

We synthesised a polyaniline/mica (Mica-PANI) nanocomposite using naturally occurring muscovite mica by a top-down approach. The developed coating materials were characterised using a different technique to investigate their chemical and structural properties using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). Furthermore, the electrochemical properties of the coating materials were investigated by linear sweep voltammetry (LSV). SEM images elucidate the composite's average particle diameter of the prepared nano-mica, approximately 80 nm. The existence of relevant functional groups and bonding in the prepared Mica-PANI composite material was confirmed by means of XPS and FTIR techniques. Moreover, the synthesised composite with 5% w/w shows high anticorrosion protection, i.e. 84 μm per year, compared to competing materials, including commercial paint and individual raw materials (0.35 mm per year). The anti-corrosive effect occurs mainly due to two opposing effects: the formation of an Fe(OH)3 passive layer on the steel surface by oxidation of surface iron atoms by the PANI and the barrier effect of mica NPs through inhibition of corrosive agents. Therefore, the eco-inspired composite could be an ideal cost-effective coating material to prevent the corrosion of mild steel surfaces.

Carbon nanofiber-reinforced shape memory polyurethanes based on HTPB/PTMG blend as anticorrosive coatings

ABSTRACT Aiming at an easy-processing shape memory polymer, we report different thermo-responsive shape memory polyurethane (SMPU) nanocomposites derived from Hydroxyl Terminated Poly-Butadiene (HTPB) and the Poly Tetra Methylene Glycol (PTMG) encapsulated with different concentrations of carbon nanofiber (CNF) in a cross-linked shape memory polyurethane (PU) matrix. By introducing the optimum concentration of the nanofiller with the PU matrix, we can improve essential properties of PU composites such as morphology, mechanical flexibility, as well as shape memory properties, which are considered the crucial requirement for the effective design of PU composites for a precise application. Two compositions of PU composites were prepared by encapsulating CNF, viz. PU-0.1CNF and PU-0.5CNF, the content of CNF being 1 wt.% and 5 wt.%, respectively. Morphological, thermal, and mechanical studies of these two PU composites show that CNF is homogeneously blended within the PU matrix and well dispersed. The thermal stability of prepared polymer films was evaluated with the help of Thermo-Gravimetry, indicating increased stability with the addition of CNF nanofillers. DSC analysis helps to determine the glass transition temperature (Tg ) as well as the shape transition temperature (Ttrans ). The tensile study confirmed that PU-0.5CNF possesses a greater Young’s modulus value and is not constant in elastic loads. The anti-corrosion property of the prepared SMPU nanocomposite coatings coated over the SS plate was evaluated using a 3.0 wt% NaCl (simulated seawater) solution. Extrapolation of Tafel plots and electrochemical impedance spectroscopy (EIS) provided a higher value of positive corrosion potential (Ecorr ) and a lower value of corrosion current (Icorr ). The electrochemical experiment results demonstrated that PU-0.1CNF nanocomposite coating on SS has better anti-corrosive properties and protection efficiency (PEF% = 98.43%) and behaves like a physical barrier to resist corrosion. These HTPB/PTMG PU nanocomposites exhibit excellent shape memory properties and have a unique composition having both the properties of anti-corrosion and shape memory effects. The results show that by properly selecting the composition we can tailor-make a PU having both anticorrosion and shape memory properties.

Assessment of Corrosion Protection Performance of FeOOH/Fe3O4/C Composite Coatings Formed In Situ on the Surface of Fe Metal in Air-Saturated 3.5 wt.% NaCl Solution

The purpose of this work is to evaluate the corrosion-inhibition behavior of deposited carbon and some iron-oxide hybrid coatings which derived from the in situ deposition method on the surface of Fe foil. Various contents of precursor methane gas were deposited over a mild iron foil substrate and formed different composites. It was found that the incorporation of C into the Fe matrix led to a thin film on the surface of the matrix and produced an anti-corrosion effect. Electrochemical impedance spectroscopy (EIS), potentiodynamic polarization and potentiometric tests were used to compare the corrosion behaviors of the films in air-saturated 3.5 wt.% NaCl solution. According to the results, Fe-oxide- and C-composite-coated iron foil has a much higher corrosion resistance than the raw blank sample without the addition of C. Generally, the corrosion charge transfer resistance of one kind of iron oxide coated with carbon layers of several nanometers was enhanced up to 28,379 times (Rct changes from 1487 Ω cm2 to 4.22 × 107 Ω cm2), which is the biggest improvement so far. The maximum protection efficiency was obtained for the in situ grown coating prepared by 10 and 15 sccm CH4 precursor gas (eta = 100%). In conclusion, an iron oxide and carbon composite was found to be a great candidate for applications in the corrosion-resistance area.

Theoretical evaluation of spirocyclic compounds as green corrosion inhibitors for carbon steel

The Corrosion inhibition efficiency of some spirocyclic compounds in the presence of HCl 0.1 M as a corrosive electrolyte was explored using density functional theory (DFT) calculations and molecular dynamics (MD) simulations. All DFT calculations were performed using B3LYP functional in conjunction with 6-31+G(d) and 6-311++G(d,p) basis sets at both gas and solvent phases for protonated and neutral forms of inhibitory molecules. The highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energy levels, HOMO-LUMO energy gap, quantum molecular descriptors, and thermochemical parameters were calculated to determine the most effective corrosion inhibitors. MD simulations revealed that the adsorption energies (Eads) of the inhibitors on steel are dependent on the number of molecules introduced in the simulated systems. The more inhibitory molecules are adsorbed on the Fe substrate, the more anti-corrosion effect they have. The most negative Eads value observed occurs at 308 K, while it decreases at 318 K for all the other simulated systems, resulting in one of the molecules being identified as a potential carbon steel corrosion inhibitor for further experiments.

Plasma‐electrified postharvest preservation of Citrus sinensis: Process technology and freshness‐keeping and anticorrosion effects

AbstractNitrogen oxide‐generating dielectric barrier discharge plasma is shown to effectively inhibit microorganisms and maintain fruit freshness. Physical and biological mechanisms of the plasma‐electrified fungicidal effects suggest that plasma‐generated NO and ONOO− species and other factors are crucial to regulating physiological senescence in citrus fruit while controlling pathogens on their surface. The revealed Physico‐chemical effects explain the observed phenotypic changes and the suppression of surface pathogens, thus providing mechanistic insights into postharvest fruit processing with plasmas.

OBTAINING ANTI-CORROSION COMPOSITIONS BASED ON SECONDARY POLYPROPYLENE AND POLYETHYLENE TEREPHTHALATE

In the article, the issues of obtaining new anti-corrosion compositions for protecting the bottom of oil storage tanks from corrosion. It is shown that the available domestic materials for the production of anti-corrosion protective coatings have not yet been widely used to protect the equipment of oil production and storage facilities from corrosion. One of the ways to solve this problem is the development of new anti-corrosion compositions based on secondary polymers and some natural resins. The composition of a new composite material for corrosion protection of the bottom of oil storage tanks is proposed. Polymer compositions were obtained by mixing the components in a laboratory multifunctional extruder. Based on spectral studies, a conclusion was made about the structure of the composite, it was shown that the most probable chemical processes occurring in the extruder are the interaction of vinyl acetate with gossypol, its derivatives, as well as molecules of free fatty acids of gossypol resin. The obtained microscopic images of corrosion products on the metal surface of the bottom of the metal of the tank allow us to state that under these conditions, pitting corrosion occurs, the penetration depth of the needle is 4–6 mm/year. The addition of gossypol resin and savilen to the composition of the composite promotes inhibition of the rate of the oxidative degradation process, and additionally increases adhesion to the metal surface by 10-15%. The resulting composition of polymeric anticorrosion compositions based on sevilen, secondary polypropylene, crushed polyethylene terephthalate and gossypol resin is an effective anticorrosion coating and can be used to protect the bottom of oil storage tanks from corrosion.