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The present research work investigated the influence of biodegradable polymer coatings of hemp fiber on the structural, water absorption, mechanical, and tribological properties of hemp fiber and hemp fiber reinforced epoxy composites (HFREC). Hemp fibers were initially treated with sodium hydrogen carbonate and then coated with biodegradable polymers like polyhydroxybutyrate (PHB) and polylactic acid (PLA). Scanning electron microscopy (SEM) images of the coated fibers showed a visible change in fiber surface and improvement in surface roughness, while; X-Ray diffraction (XRD) analysis indicated the improvement in crystallinity of the coated fibers resulting in enhanced interfacial adhesion between the coated fibers and the epoxy matrix. The experimental results also revealed that both PHB and PLA coatings of the fibers have resulted in improvement of water resistance and mechanical properties such as tensile strength, modulus, and impact strength of coated HFREC. Tribological test results also revealed that the coated HFREC have improved wear and frictional properties in comparison to uncoated HFREC. The best tribological and mechanical properties were exhibited by PLA coated HFREC, which was also confirmed through the SEM images of worn and fractured surfaces of the uncoated and coated hemp fiber composites. [ABSTRACT FROM AUTHOR]

This paper focuses on the manufacturing and quality evaluation of fibre-reinforced polymer matrix composite coatings deposited by hand lamination on DC04 steel substrates. Two matrices (polyurethane and epoxy resins) and four different reinforcement materials were considered (glass, carbon, aramid, and carbon-aramid hybrid fabrics). Various methods of surface preparation and roughness development were used in order to enhance the adhesion: cleaning with acetone, abrasive blasting with F80 alumina or GH40 cast steel shot. Manufactured samples were subjected to roughness and coating thickness measurements, wettability analysis, and pull-off strength tests. Afterwards, the microscopic analysis of cross-sections of the samples and the identification of type of the failure were performed. The increase in surface roughness was beneficial, to some point, for the coating's adhesion. The highest pull-off strength values were obtained for polyurethane coating reinforced with glass fabric after abrasive blasting with the use of F80 alumina (5.78 MPa) and epoxy resin with aramid reinforcement (5.20 MPa) after pretreatment with GH40 cast steel shot. [ABSTRACT FROM AUTHOR]

Lithium metal batteries are next‐generation energy storage devices that rely on the stable electrodeposition of lithium metal during the charging process. The major challenge associated with this battery chemistry is related to the uneven deposition that leads to dendritic growth and poor coulombic efficiency (CE). A promising strategy for addressing this challenge is utilizing a polymer coating on the anodic surface. While several works in the past have evaluated polymer coatings, the requirements for polymer design are still unclear. In this work, the effect of polymer dynamics on lithium metal deposition is specifically investigated. Electrolyte (solvent) blocking perfluoropolyether polymer networks with evenly spaced H‐bonding sites of various strengths are designed, resulting in significant differences in the molecular ordering, as analyzed by X‐ray scattering measurements. The differences in the H‐bonding strength directly impact the mechanical properties of these materials, thus providing a controlled set of samples with a range of polymer dynamics for electrodeposition studies. Finally, a systematic evaluation of the lithium metal electrodeposition quality with these polymers as anodic coating shows that polymers with flowability or faster polymer dynamics exhibit higher CE. These experimental findings provide rational design principles for soft polymer coatings on lithium metal anodes. [ABSTRACT FROM AUTHOR]

Electrochemical sensors for the simultaneous determination of natural or synthetic phenolic antioxidants, their analytical characteristics, advantages, and disadvantages are considered. The data are systematized by the type of the sensitive layer of the sensor responding to the target analytes, including carbon nanomaterials, nanoparticles of metal oxides, polymer coatings, and their various combinations. The methods of obtaining the considered sensors, their advantages, and disadvantages are also discussed. In conclusion, the directions of the further development of the electroanalysis of structurally related phenolic antioxidants are considered. [ABSTRACT FROM AUTHOR]

Recent literature concerning the use of polymer and ceramic coatings for a variety of biomedical applications is surveyed in this review. Applications have been grouped into six broad categories: orthopaedic materials, cardiovascular stents, antibacterial surfaces, drug delivery, tissue engineering and biosensors. Polymer and ceramic coatings add enhanced corrosion protection, antiwear, antibacterial and biocompatibility properties to various substrates for biomedical applications. Processes favoured for polymer coating formation included dip, electrodeposition, spin (including electrospin) and spray (including electrospray and ultrasonic spray). Ceramic coatings were formed using magnetron sputtering and a combination of 3-D printing and in-situ mineralisation, among others. The review period is from 2017 to the present (mid-2021). [ABSTRACT FROM AUTHOR]

Abstract—The electrochemical properties of protective epoxy polymer coatings with different designs are studied with electrochemical impedance spectroscopy upon exposure in water and aqueous solutions of sulfuric acid. It is found that both the active resistance of the epoxy coating Rct and resistance of the transition layer Rdl decrease upon long-term exposure both in water and diluted acid. There is correlation between the decrease in Rct with the depth of penetration of the acid front for multilayer coatings. For acids with moderate concentrations, the active resistance of the epoxy coating Rct also decreases in the case of increases in the time of exposure, while the resistance of the transition layer Rdl goes over to a growth after the initial drop, well before the penetration of the acid to the substrate. A correlation of the resistance of the transition layer Rdl with the fraction of underfilm corrosion is found for the case of corrosion in water. A model for the estimation of the fraction of underfilm corrosion by the change in the resistance of the transition layer is proposed and verified. [ABSTRACT FROM AUTHOR]

Upconversion nanoparticles (UCNPs) are materials that provide unique advantages for biomedical applications. There are constantly emerging customized UCNPs with varying compositions, coatings, and upconversion mechanisms. Cellular uptake is a key parameter for the biological application of UCNPs. Uptake experiments have yielded highly varying results, and correlating trends between cellular uptake with different types of UCNP coatings remains challenging. In this report, the impact of surface polymer coatings on the formation of protein coronas and subsequent cellular uptake of UCNPs by macrophages and cancer cells was investigated. Luminescence confocal microscopy and elemental analysis techniques were used to evaluate the different coatings for internalization within cells. Pathway inhibitors were used to unravel the specific internalization mechanisms of polymer-coated UCNPs. Coatings were chosen as the most promising for colloidal stability, conjugation chemistry, and biomedical applications. PIMA-PEG (poly(isobutylene- alt -maleic) anhydride with polyethylene glycol)-coated UCNPs were found to have low cytotoxicity, low uptake by macrophages (when compared with PEI, poly(ethylenimine)), and sufficient uptake by tumor cells for surface-loaded drug delivery applications. Inductively coupled plasma-optical emission spectroscopy (ICP-OES) studies revealed that PIMA-coated NPs were preferentially internalized by the clathrin- and caveolar-independent pathways, with a preference for clathrin-mediated uptake at longer time points. PMAO-PEG (poly(maleic anhydride- alt -1-octadecene) with polyethylene glycol)-coated UCNPs were internalized by energy-dependent pathways, while PAA- (poly(acrylic acid)) and PEI-coated NPs were internalized by multifactorial mechanisms of internalization. The results indicate that copolymers of PIMA-PEG coatings on UCNPs were well suited for the next-generation of biomedical applications.

Modifying the interface between the lithium metal anode (LMA) and the electrolyte is crucial for achieving high-performance lithium metal batteries (LMBs). Recent research indicates that altering Li-metal interfaces with polymer coatings is an effective approach to extend LMBs' cycling lifespan. However, the physical properties of these polymer-Li interfaces have not yet been fully investigated. Therefore, the structural stability, electronic conductivity, and ionic conductivity of polymer-Li interfaces were examined based on first-principles calculations in this study. Several representative polymer compounds utilized in LMBs were assessed, including polyacrylonitrile (PAN), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), and polyethylene oxide (PEO). Our research revealed that lithium fluoride is formed upon fluoropolymer degradation, explaining previously observed experimental results. Polymers containing nitrile groups exhibit strong adhesion to lithium metal, facilitating the formation of the stable interface layer. Regarding electronic conductivity, the fluoropolymers preserve a good insulating property, which diminished marginally in the presence of lithium, but that of PAN and PEO significantly reduces. Additionally, lithium diffusion on PTFE and PEO demonstrates low diffusion barriers and high coefficients, enabling easy transportation. Overall, our investigation reveals that the interfaces formed between various polymers and LMA have distinct characteristics, providing new fundamental insights for designing composites with tailored interface properties., (© 2024 Wiley-VCH GmbH.)

A versatile one‐step synthesis of surface‐attached polymer networks using small bifunctional gelators (SBG), namely 4‐azidosulfonylphenethyltrimethoxysilane (4‐ASPTMS) and 6‐azidosulfonylhexyltriethoxysilane (6‐ASHTES) is reported. A thin layer (≈200 nm) of a mixture comprising ≈90% precursor polymer and 10% of 4‐ASPTMS or 10% 6‐ASHTES on a silicon wafer is deposited. Upon UV irradiation (≈l–254 nm) or annealing (>100 °C) layers, sulfonyl azides (SAz) release nitrogen by forming singlet and triplet nitrenes that concurrently react with any C─H bond in the vicinity resulting in sulfonamide crosslinks. Condensation among tri‐alkoxy groups (i.e., methoxy or ethoxy) in bulk connects the SBG units, which completes the crosslinking. Concurrently, when such functionalities react with hydroxyl groups at the surface, which enable the covalent attachment of the crosslinked polymer chains. A systematic investigation on reaction mechanism and gel formation using spectroscopic ellipsometry (SE) and Fourier‐transform infrared spectroscopy in the attenuated total reflection mode (FTIR‐ATR) is performed. Analogous thermally initiated gelation for both 4‐ASPTMS and 6‐ASHTES is found. The 6‐ASHTES is UV inactive at ≈l–254 nm, while the 4‐ASPTMS is active and forms gels. The difference is attributed to the aromatic nature of 4‐ASPTMS that absorb UV light at ≈l–254 nm due to π–π* transition. [ABSTRACT FROM AUTHOR]

A solvent-free route of initiated chemical vapor deposition (iCVD) was used to synthesize a bio-renewable poly(α-Methylene-γ-butyrolactone) (PMBL) polymer. α-MBL, also known as tulipalin A, is a bio-based monomer that can be a sustainable alternative to produce polymer coatings with interesting material properties. The produced polymers were deposited as thin films on three different types of substrates—polycarbonate (PC) sheets, microscopic glass, and silicon wafers—and characterized via an array of characterization techniques, including Fourier-transform infrared (FTIR), proton nuclear magnetic resonance spectroscopy (1H NMR), ultraviolet visible spectroscopy (UV–vis), differential scanning calorimetry (DSC), size-exclusion chromatography (SEC), and thermogravimetric analysis (TGA). Optically transparent thin films and coatings of PMBL were found to have high thermal stability up to 310 °C. The resulting PMBL films also displayed good optical characteristics, and a high glass transition temperature (Tg~164 °C), higher than the Tg of its structurally resembling fossil-based linear analogue-poly(methyl methacrylate). The effect of monomer partial pressure to monomer saturation vapor pressure (Pm/Psat) on the deposition rate was investigated in this study. Both the deposition rate and molar masses increased linearly with Pm/Psat following the normal iCVD mechanism and kinetics that have been reported in literature.

To address the challenging issues of metal materials corrosion in industries, which has caused huge economic losses and security threats to many facilities in marine environments, functional polymer coatings have been widely used and regarded as one of the simplest and most effective methods to prevent such an undesirable event. In this study, a new type of coating filler consisting of graphene oxide/polyaniline/polydopamine (GO-PANI-PDA) nanocomposites has been successfully synthesized. The morphology, structure, composition, and corrosion resistance performance of the GO-PANI-PDA (GPP) nanocomposites were investigated via a series of characterization methods. The results from our electrochemical impedance spectroscopy, potentiodynamic polarization curve and salt spray experiment showed that the best corrosion resistance performance of the coating is from GPP 21 with the epoxy/GO-PANI:PDA ratio of 2:1, which exhibited a positive corrosion potential (−0.51 V) shift from epoxy/GO-PANI coating (−0.64 V). The corrosion current density (3.83 × 10−8 A/cm2) of GPP 21 is nearly an order of magnitude lower than that of epoxy/GO-PANI (7.05 × 10−7 A/cm2). The good anti-corrosion performance was fascinatingly observed in salt spray tests even without obvious corrosion phenomenon after 30 days of testing. Due to these remarkable properties, GPP nanocomposites can be an outstanding candidate for the rapid development of broadband shielding and anticorrosive materials.

Surface characterization techniques for organic polymeric coatings are numerous and diverse. Many of these techniques can provide physical information about how coating systems perform under certain environmental conditions, but they provide less mechanistic information on how they function as corrosion barriers. Since many coating failures are initiated from ionic diffusion through the coating and the subsequent reactivity at the coating–metal interface is mostly electrochemical in nature, the utility of electrochemical‐based techniques is therefore more appropriate. This mini‐review highlights five of the most commonly used electroanalytical techniques for the evaluation of corrosion protection properties for polymer coatings on metals: open circuit potential, electrochemical impedance spectroscopy, potentiodynamic polarization, electrochemical noise and scanning electrochemical microscopy. These techniques can perform their own unique approach of examining the protection performance of polymer coatings, but the elucidation of coating degradation and mechanism of corrosion at the coating–metal interface is their common objective. © 2020 Society of Industrial Chemistry [ABSTRACT FROM AUTHOR]

Self-lubricating polymer composite coatings, with tailorable tribological and mechanical properties, have been widely employed on mechanical parts to reduce friction and wear, which saves energy and improves the overall performance for applications such as aerospace satellite parts, shafts, gears, and bushings. The addition of functional fillers can overcome the limitations of single-polymer coatings and extend the service life of the coatings by providing a combination of low friction, high wear resistance, high load bearing, high temperature resistance, and high adhesion. This paper compares the heat resistance, and the tribological and mechanical properties of common polymer matrices, as well as the categories of functional fillers that improve the coating performance. Applicable scopes, process parameters, advantages, and limitations of the preparation methods of polymer coatings are discussed in detail. The tribological properties of the composite coatings with different matrices and fillers are compared, and the lubrication mechanisms are analyzed. Fillers reduce friction by promoting the formation of transfer films or liquid shear films. Improvement of the mechanical properties of the composite coatings with fillers of different morphologies is described in terms of strengthening and toughening mechanisms, including a stress transfer mechanism, shear yielding, crack bridging, and interfacial debonding. The test and enhancement methods for the adhesion properties between the coating and substrate are discussed. The coating adhesion can be enhanced through mechanical treatment, chemical treatment, and energy treatment of the substrate. Finally, we propose the design strategies for high-performance polymer composite coating systems adapted to specific operating conditions, and the limitations of current polymer composite coating research are identified. [ABSTRACT FROM AUTHOR]

Polyvinyl alcohol (PVA) and silver nanoparticles/poly(vinyl) alcohol system (nAg/PVA) were investigated as copper corrosion inhibitors in hydrochloric acid solution by electrochemical measurements, such as potentiodynamic polarization and cyclic voltammetry associated with the atomic force microscopy (AFM) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDS) analysis. The potentiodynamic curves processed as a semilogarithmic diagram were employed for corrosion current density (icorr) computing that reached the highest value for copper corrosion in uninhibited hydrochloric acid solution and the lowest value in nAg/PVA inhibitor presence, resulting in a picked-up inhibition performance, greater than 95%. Recording ten cycles of CV, the initiation, development and stability of upper-layer formed on the copper surface in the presence of inhibitors was confirmed. It can be asserted that PVA acts by the adsorption of Cu(II)-PVA complexes or crosslinked PVA-copper aggregates and additionally, in the presence of nAg/PVA of some compounds involving silver attached to PVA. AFM 3D images showed completely different morphologies of the copper surface layers formed in the absence and presence of inhibitors. Just like AFM, a more regular and uniform arrangement of the surface layer, due to the silver interconnected to PVA macromolecular chain, was displayed by scanning electron microscopy (SEM) images.

Pre-painted sheet metal (e.g. coil coated with polyester-melamine) undergoes large deformations when formed into architectural cladding or white goods. The coatings provide protection and superior aesthetics, so must withstand failure by cracking or delamination during forming. The T-bend test is an industry standard test used to qualitatively compare the formability of coatings and mimics the conditions experienced during hemming processes. The failure of coatings during forming is strain governed, so understanding the surface strains in the T-bend test is of great interest to manufacturers. For the first time, the maximum surface strains experienced during the T-bend test have been predicted using finite element modelling (FEM) and verified experimentally using digital image correlation. The experimental shapes of the deformed blank are compared with the FEM results for further verification. In addition, a novel analytical model is proposed to determine the maximum surface strains. It is shown that strains of up to ~ 225% are applied during a 0T test (bent around a zero thickness spacer) reducing to ~ 23% at 4T (bent around a four times sheet thickness spacer). The finite element model, experimental data and new analytical model show excellent agreement and indicate that behaviour is independent of the substrate thickness or material used. Understanding the strain behaviour quantifies the formerly qualitative T-bend. This will improve the efficacy of the test, allowing metal formers and coating developers to better understand the performance requirements, to reduce waste and to develop better coatings. [ABSTRACT FROM AUTHOR]

Characterizing the mechanical properties of polymer coatings typically requires access to specialty equipment, the analysis through which can be tedious despite instrumental precision. An alternative method reported in the literature, strain-induced elastic buckling instability for mechanical measurements (SIEBIMM), is a high throughput, facile yet accurate method, used to characterize the Young's modulus of supported films and coatings. SIEBIMM can easily be implemented in both academic and industrial settings. Hypothesis: We hypothesize that the SIEBIMM method has an upper coating thickness limit beyond which the assumptions and practicality of the method are no longer valid. Experiments: The Young's moduli of model polyvinyl alcohol coatings (on polydimethylsiloxane substrates) with thicknesses ranging from 67 nm to 40 µm were determined using the SIEBIMM method and the data were subjected to a rigorous statistical analysis. Findings: SIEBIMM could accurately characterize coatings up to 35 µm thick. The Young's modulus of all coatings ≤ 35 µm was 1.6 ± 0.1 GPa at 50% RH, which agreed with free-standing polyvinyl alcohol films measured by traditional tensile testing. For the method to be used on thicker coatings, it is essential to consistently measure coating thickness and buckling wavelength at the same location to minimize potential error. [ABSTRACT FROM AUTHOR]

This paper describes the synthesis and use of multifunctional methacrylic monomers, which contain basic (amine) functional groups, including an example in which an acid-labile tert -butylcarbamate-protected glycine is used to form a novel methacrylic monomer. The "protected" amino acid-derived functional monomer (BOC-Gly-MA) is copolymerized with an epoxide functional methacrylic monomer (GMA), to deliver novel multifunctional polymers, which are processed into powder coatings and used to study filiform corrosion at the surface of an aluminum substrate. The BOC-Gly-MA-containing copolymers were shown to improve a coating's anticorrosion performance, presenting the lowest average filiform corrosion (FFC) track length, total FFC number, and total corroded surface area (CSA) of the coatings investigated. Further to this, a mode of action for the role of BOC-Gly functional polymers in corrosion protection is proposed, supported by both solution and polymer-aluminum interface studies, delivering new insights into the mode of action of pH-responsive polymer coatings.

Nanopore‐based resistive‐pulse recordings represent a promising approach for single‐molecule biophysics with applications ranging from rapid DNA and RNA sequencing to "fingerprinting" proteins. Based on advances in fabrication methods, solid‐state nanopores are increasingly providing an alternative to proteinaceous nanopores from living organisms; their widespread adoption is, however, slowed by nonspecific interactions between biomolecules and pore walls, which can cause artifacts and pore clogging. Although efforts to minimize these interactions by tailoring surface chemistry using various physisorbed or chemisorbed coatings have made progress, a straightforward, robust, and effective coating method is needed to improve the robustness of nanopore recordings. Here, covalently attached nanopore surface coatings are prepared from three different polymers using a straightforward "dip and rinse" approach and compared to each other regarding their ability to minimize nonspecific interactions with proteins. It is demonstrated that polymer coatings approach the performance of fluid lipid coatings with respect to minimizing these interactions. Moreover, these polymer coatings enable accurate estimates of the volumes and spheroidal shapes of freely translocating proteins; uncoated or inadequately coated solid‐state pores do not have this capability. In addition, these polymer coatings impart physical and chemical stability and enable efficient and label‐free characterization of single proteins without requiring harsh cleaning protocols between experiments. [ABSTRACT FROM AUTHOR]

Icephobic coatings interest various industries facing icing problems. However, their durability represents a current limitation in real applications. Therefore, understanding the degradation of coatings under various environmental stresses is necessary for further coating development. Here, lubricated icephobic coatings were fabricated using a flame spray method with hybrid feedstock injection. Low-density polyethylene represented the main coating component. Two additives, namely fully hydrogenated cottonseed oil and paraffinic wax, were added to the coating structure to enhance coating icephobicity. Coating properties were characterised, including topography, surface roughness, thermal properties, wettability, and icephobicity. Moreover, their performance was investigated under various environmental stresses, such as repeated icing/deicing cycles, immersion in corrosive media, and exposure to ultraviolet (UV) irradiation. According to the results, all coatings exhibited medium-low ice adhesion, with slightly more stable icephobic behaviour for cottonseed oil-based coatings over the icing/deicing cycles. Surface roughness slightly increased, and wetting performances decreased after the cyclic tests, but chemical changes were not revealed. Moreover, coatings demonstrated good chemical resistance in selected corrosive media, with better performance for paraffin-based coatings. However, a slight decrease in hydrophobicity was detected due to surface structural changes. Finally, paraffin-based coatings showed better resistance under UV irradiation based on carbonyl index and colour change measurements.

Cleaning is one of the most important and delicate operations in the conservation of cultural heritage, and, if not correctly performed, may irreversibly damage works of art. The removal of aged or detrimental polymeric coatings from works of art is a common operation in conservation, and nanostructured fluids (NSFs), such as aqueous swollen micelles and oil-in-water (o/w) microemulsions, are used as an alternative to non-confined organic solvents, which pose a series of non-negligible drawbacks. NSFs effectiveness in removing polymeric coatings has been thoroughly demonstrated in the last decades, while their cleaning mechanism is still under investigation. The present work deepens the knowledge on the removal mechanisms of NSFs, studying the interaction of a four-component NSF with four different types of acrylic and vinyl polymer films cast from solutions or aqueous polymer latexes on three substrates (glass, marble, and polystyrene) with different hydrophilicity and wettability. NSFs were applied either as non-confined or confined in cellulose poultices (traditionally employed by conservators), or in highly retentive chemical gels, observing the influence of the confining matrix on the removal process. It was found that the NSF/polymer film interaction is greatly dependent on the film structure and composition. Films formed from solvent solutions can be swollen by water/organic solvents mixtures or dewetted when a surfactant is added to the cleaning fluid; films formed from polymer latexes, on the other hand, are generally swollen even just by water alone, but poorly dewet. The substrate also plays an important role in the removal of polymer films formed from solutions, for instance the removal of an acrylic polymer from polystyrene could be achieved only through highly selective cleaning using NSF-loaded chemical hydrogels. These results can be key for conservators, providing innovative solutions to face new challenges in art preservation.

Armies of powerful armed forces are already applying achievements of nanoscience and supporting researches in the field of nanotechnology. This paper surveys the recent research in the area of nanomaterials application in defence technologies, conducted in the Military Technical Institute in Belgrade, Serbia. This research covers the most important results obtained so far in the following areas: chemical biological, radiological and nuclear protection (CBRN protection), nanomodified polymer coatings and camouflage paints, composite structures for military aircraft, ballistic protection composites, and energetic materials. Researches gave promising results in all the named fields and encourage nanomaterials application in future.

The use of encapsulated fertilizers and pesticides is a key approach for slowing the release of agrochemicals, while simultaneously reducing costs and environmental problems. The use of hybrid systems for encapsulation in organic‐based agriculture, which enables the release of agrochemicals in a single application, has been a growing field. In this approach, a formulation of Bacillus‐thuringiensis as bio‐pesticide and nitrogen, phosphorus, and potassium fertilizer (fish emulsion, potassium nitrate, and potassium phosphate) were formulated using superabsorbent polymers microbeads based on sodium alginate (ALG) then evaluated for release. Different formulations were prepared using 15 wt% of Bt, fish emulsion, nitrogen, and phosphorus. The encapsulated microbeads were prepared by wet‐extrusion processing using sodium alginate as the superabsorbent polymer and calcium chloride as the gelling agent. The resulting beads were characterized in terms of size, morphology, water uptake, and biodegradability. The results showed that the prepared microbeads have narrow size distributions (1.2 to 2.1 mm) and increased water uptake (1,200–3,200%). Moreover, loaded microbeads were analyzed using inductively coupled plasma‐optical emission spectroscopy and Elementar CHNS analyzer to obtain the fertilizer grades as (6.2–0.8–1.05), (0–6.3–6.4), and (0.62–0–2.4) for the one loaded with fish emulsion, for potassium phosphate loaded beads, and for potassium nitrate loaded beads, respectively. [ABSTRACT FROM AUTHOR]

To form a network polymer structure of melamine-formaldehyde alkyd paints and varnishes (APV) oligomeric film formers modified with vegetable oils or their fatty acids, alkyd resins and varnishes, as well as materials based on amino formaldehyde resins plasticized with polyethers (alkyd resins) are used. The main disadvantage of APV is the long drying time in the air (it takes more than a day to dry one layer), unsatisfactory decorative and protective performance of coatings, their unstable resistance to atmospheric and environmental influences. Melamine alkyd APV can withstand longer and aggressive weathering, but the process of hardening occurs at high temperatures with significant energy consumption, the process is time consuming and unsuitable for modern technologies for assembling devices, machines, engineering structures in combination with different materials. The aim of our research was to improve existing APV based on amino formaldehyde resins and creating new film formers using oligomeric cyclic carbonates and oligomeric amines in order to improve the properties of materials. The modification of melamine-alkyd paints and varnishes with compounds contained high content of polar groups and capable to form chemical and physical bonds with active groups of functionalized plant oligomers is a promising way to improve the properties. A three-step method of synthesis urethane-containing modifier based on carbonized vegetable oil, aminoethyl piperazine, maleic anhydride and melamine alkyd resin was developed to obtain new polymer coatings. The synthesized modifier - amido urethane maleate based on vegetable oil is characterized by the presence of numerous active groups that interact with melamine alkyd resin K-421 and PF-060 to form a branched polymer structure that is stable during storage. Modified APV samples with 10% and 15% of oligoamidurethane maleate have been developed, which are characterized by enhanced physico-mechanical, adhesive and processing properties and can be recommended for practical application in various coating technologies. The structural features of the initial reagents and the obtained products were studied by FTIR spectroscopy. [ABSTRACT FROM AUTHOR]

Two approaches to obtain fast‐degrading polymer films based on poly(sebacic anhydride) (PSA) are presented, both of which target polymer films with a lower degree of crystallinity than pure PSA homopolymer: first, thin films are prepared from poly(adipic anhydride)/poly(sebacic anhydride) blends at different ratios, and second, films are made from the copolymer poly(salicylic acid‐co‐sebacic acid). These films are intended as sacrificial layers for self‐regenerating functional coatings, for example, to regenerate antimicrobial surface activity. The degradation kinetics of these films are analyzed by surface plasmon resonance spectroscopy. The results of the blends approach indicate that the blend degradation rate is accelerated only in the initial degradation phase (compared to PSA). The degradation kinetics study of the poly(salicylic‐acid‐co‐sebacic acid) film shows that this copolymer degrades faster than poly(sebacic anhydride) initially, releasing antimicrobial salicylic acid in the process. However, its degradation rate slows down at a mass loss >60% and approaches the PSA degradation curve at longer degradation times. When tested as sacrificial layer in self‐regenerating antimicrobial polymer stacks, it is found that the degradation rate is too low for successful layer shedding. [ABSTRACT FROM AUTHOR]

It is shown that coatings for internal surfaces of the working equipment of road machinery must have good adhesion to the material of the working tools, stable release properties to the processed working media, and good resistance to climatic factors. Various types of fillers are considered, which allow increasing the resistance of protective coatings of the working equipment of road machinery to the influence of climatic factors. The results of experimental studies of evaluating the resistance of polymer coatings with various types of fillers to moisture and freezing temperatures are presented. Photos of the structure of polymer coatings before and after climatic tests are given. [ABSTRACT FROM AUTHOR]

There is a necessity to develop highly efficient wear-resistant materials and coatings in order to create reliable modern technology. The latter is needed to ensure reliable and durable friction assembly of mechanisms, operated in a wide range of loads, speeds, temperatures, and operable in aggressive environments, under transient conditions and in vacuum. Since any materials have certain disadvantages, they are often used with additives. The main idea of the study is based on analyzing the dependence of the tribological properties of nanocomposite polymers, to suggest the spatial organization of a nanocomposite (nano-inclusions in a polymer matrix or a nanostructured polymer matrix) with enhanced tribological properties. Substantiation, development and research on tribocomposites, obtained by the methods of physical and chemical design. The main problem of nanocomposites is the tendency to undergo aggregation of nanoparticles, and in the oxidation of metal-containing nanoparticles. In this regard, it seems appropriate enough to put nanoparticles into the polymer matrix body in an organized manner, to apply the idea of creating spatial ordering in the distribution structure of nanoparticles in a polymer matrix. As a possible solution, a nonocomposite of the following composition is proposed: a nanoporous matrix with a regular arrangement of pores, containing nanoinclusions and with different fillers, as well as a method for producing such polymeric environments. [ABSTRACT FROM AUTHOR]

The effect exerted on rheological properties of polymer compounds by core-shell pigments with a shell of doped and undoped polyaniline was studied. In the presence of core-shell pigments with a doped polyaniline shell, the limiting content of the gel fraction increases, but the polymer network becomes less dense. Polarization studies show that the use of pigments with an undoped polyaniline shell leads to stronger inhibition of the corrosion process. As shown by electrochemical impedance spectroscopy, introduction of core—shell pigments enhances the protective properties of the coatings formed. [ABSTRACT FROM AUTHOR]

Protective properties of polymer coatings are mainly determined by their adhesion properties. Organosilanes represent the most commonly applied adhesion promoters; they are also capable of decelerating corrosion processes. In this study, the possibility of applying organosilanes in the function of inhibitors of cathodic peeling-off of polymer coatings has been investigated. It has been established that the introduction of vinyl silane to the coating results in the inhibition of cathodic peeling-off due to higher compatibility of vinyl with the components of the bitumen-polymer coating. [ABSTRACT FROM AUTHOR]

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• Thermal performance of novel polymer nanocomposite coatings towards anti-fouling and anti-wetting behaviour on steel substrates is analysed. • The incorporation of reduced graphene oxide lead to a significant reduction in the wettability and surface roughness of coatings. • It is found that even small thickness of bio-foulant layer can significantly impede the heat transfer across the substrate. • In case of the epoxy-based nanocomposite coatings an ∼18° increase in contact angle was observed with the addition of rGO. This paper presents an experimental study on the thermal performance of novel polymer nanocomposite coatings under the fouling environments with particular emphasis on their ability to exhibit anti-fouling and anti-wetting behaviour. Two different weight fractions at 0.3%, and 0.5% of the reduced graphene oxide/Epoxy (rGO-ER7004) and reduced graphene oxide/polyurethane (rGO-UR9002) coatings were applied to stainless steel substrates by a facile spray coating technique. To evaluate the anti-fouling performance of the coatings, the specimens were immersed in the Modified Baar's Medium for 672 h. The antifouling performance was evaluated by comparing the overall heat transfer effectiveness of the nano coated and bare specimens at different immersion intervals. Three different flow rates, viz. 4 lpm, 6 lpm and 8 lpm were used to compare the heat transfer effectiveness. The incorporation of rGO lead to a significant reduction in the wettability and surface roughness of coatings. amongst all the investigated coatings, the heat exchange with rGO/UR9002 0.5 wt.% coatings showed the highest heat transfer effectiveness. A small reduction (∼10%) in the heat transfer effectiveness after an immersion in the fouling media for 672 h was noticed. This can be attributed to the accumulation of salt particles on the coatings, observed visually. Finally, the 1-D heat transfer analysis is performed using finite element method based approach to evaluate the effect of the nano coatings and foulants on the temperature drop. It is deduced that a small foulant layer can significantly impede the heat transfer across the substrate. A strong correlation (∼0.99) between the heat transfer effectiveness and temperature drop is observed. [ABSTRACT FROM AUTHOR]

Polymer coatings are one of the most common methods for protecting metal structures from corrosion damage. For example, in the oil and gas industry, polymer coatings are used to protect the inner surfaces of oilfield pipelines. Forecasting the service life of the coating is an unsolved problem. Existing test methods allow to assess the quality of coating application and compliance with the declared properties, for example, resistance at a certain temperature, but do not allow to understand the expected service life or degradation dynamics. One solution to this problem may be the development of existing methods of autoclave testing of coatings with the addition of more criteria for assessing degradation. This paper considers the methodological features of autoclave testing with rapid pressure relief. The decompression autoclave test was considered from the point of view of the principles of its conduct and evaluation of test results. The tests were carried out in environments containing hydrogen sulfide and carbon dioxide. The main object of the tests was anticorrosive polymer powder coatings applied in industrial conditions. The work assessed the influence of the following factors on the test result: pressure relief time, test cycle, and coating quality. Attention was also paid to the evaluation methods; aside from the adhesion assessment, optical microscopy and the evaluation of the microhardness of coatings were used. As a result of the work carried out, it was shown that the pressure relief rate within 5 s affects the test results. An increase in micropores and a drop in the microhardness of coatings after cyclic autoclave tests were also shown. The method of assessing the degradation of coatings using microhardness also showed the convergence of the results with the traditional method of assessing adhesion. The results of the work can be used to modify the autoclave testing method and transition to resource forecasting.

In recent years much work has been conducted in order to create patterned and structured polymer coatings using vapor deposition techniques – not only via post-deposition treatment, but also directly during the deposition process. Two-dimensional and three-dimensional structures can be achieved via various vapor deposition strategies, for instance, using masks, exploiting surface properties that lead to spatially selective deposition, via the use of additional porogens or by employing oblique angle polymerization deposition. Here, we provide a concise review of these studies.

• A comprehensive model is developed for the drying of the glassy polymeric coatings at low solvent concentration. • Model assumptions are further validated by SEM. • model predictions for the drying rate and solvent concentration profiles of the poly(styrene)-p-xylene system are found to be in satisfactory agreement with available experimental data. In this work, a comprehensive model has been developed for the drying of the glassy polymeric coatings by studying the evaporation of thin films of poly(styrene)/ p -xylene solutions. The developed model considers not only Fickian diffusion at the high solvent concentration region but also a visco-elastic contribution to diffusion at the late stages of drying. The model predictions for the drying rate and the p -xylene concentration profiles were found to be in satisfactory agreement with the available measurements. The assumptions made in the model development were further justified by Scanning Electron Microscopy (SEM). It is believed that this work could be used to further investigate the drying of glassy coatings. [ABSTRACT FROM AUTHOR]

This paper considers the main requirements on protective polymer coatings used for treating inner surfaces of road machine working tools. The characteristic of optimal kinds of fillers for polymer materials is provided. The results of experimental investigations for evaluating antiadhesive properties of coatings with various fillers exposed to working materials at positive and subzero temperatures are presented. [ABSTRACT FROM AUTHOR]

• A unified model for drying of glassy polymer coatings. • This model is based on sound non equilibrium thermodynamics principles. • Sol-Gel transition is considered. In this work, a unified model has been developed for the drying of the glassy polymeric coatings by studying the solvent evaporation from the poly(methyl methacrylate)/ethyl benzene system as a one dimensional numerical moving boundary experiment with simultaneous heat and mass transfer. The developed model is based on sound non equilibrium thermodynamics principles by considering visco-elastic contribution to diffusion at the late stage of drying. Moreover, sol-gel transition is considered to explain the high solvent concentration far away from the gas-liquid interface (drying surface) at the end of the drying experiment. The Galerkin finite element method is used to solve the model equations. The model predictions for the drying rate and solvent concentration profiles are found to be in satisfactory agreement with the available experimental data. This work can be implemented to design and optimize industrial processes. [ABSTRACT FROM AUTHOR]

• Corrosion behavior of PPy|Co 3 O 4 coated aluminum was investigated for the first time. • OXA-DBSA mix electrolyte significantly increased the adhesion of the films. • PPy|Co 3 O 4 films on the Al electrode provided a protection efficiency close to 100%. • The composite films increased the polarization resistance of Al up to 124 times. • R ct values determined from Cole-Cole diagram and equivalent circuit were compared. In this study, Polypyrrole|cobalt oxide (PPy|Co 3 O 4) composite films were obtained by the galvanostatic method in oxalic acid (OXA) and dodecyl benzene sulfonic acid (DBSA) mix electrolyte on aluminum-1050 (Al-1050). The corrosion protective effect of these films in a 0.1 M HCl corrosive medium was investigated by Tafel polarization method and impedance measurements. Characterization and surface morphology of the films were examined by Fourier transform infrared (FT-IR), Thermogravimetry (TG), Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The OXA-DBSA mix electrolyte significantly increased the homogeneity and adhesion of the films. Cobalt nanoparticles significantly reduced the thickness of the PPy film to about 13 μm from 50 μm. The composite film with the highest Co 3 O 4 level showed protection efficiency close to 100%. Polarization resistance values determined from the Cole-Cole plots showed that PPy film increased the resistance of Al-1050 by about 15 times, while the composite films increased the film resistance of Al-1050 up to 124 times, depending on the amount of Co 3 O 4 nanoparticles. It was observed that all of the films in the corrosive medium protected the surface of the Al-1050 quite well even at the end of the fifth day. [ABSTRACT FROM AUTHOR]

• Polymer-based oxidation-resistance coatings were prepared on C/C composites. • Effect of inorganic fillers on oxidation behaviour of polymer coatings is studied. • Coatings were fabricated by simple preparation technique and low temperature curing. • The polymer-based coatings can be applied to large-scale structures. • The good oxidation resistance is due to the formation of borosilicate glasses. A novel oxidation resistant thermoset polymer (MSCB) with excellent thermo-oxidative stability and good solubility was designed and synthesized. To prevent C/C composites from oxidation, a series of MSCB polymer-based coatings were prepared by precursor infiltration and thermal-curing at 300 ℃. The oxidation behaviour of the MSCB-, MSCB/TiO 2 -, MSCB/ZrO 2 - and MSCB/SiC-coated C/C composites was studied. The improved oxidation resistance of the C/C composites was attributed to the good adhesion of the coatings and the formation of a borosilicate protective layer on the surface of the coatings, which was confirmed by the results of TGA, SEM, XPS, and XRD analyses. [ABSTRACT FROM AUTHOR]

Abstract The current study explored the degradation behavior of a WE43 Mg alloy during immersion tests in Dulbecco's Modified Eagle's Medium (DMEM) for 3d and 7d, for a bare alloy surface as well as for samples with surface pre-treatment, and finally for samples coated with chitosan-bioactive glass. The immersion tests were conducted with and without addition of serum, to study the influence of proteins on the degradation process. Mass-loss was measured to determine the corrosion rate after 3d and 7d of immersion. The samples were analyzed by SEM with respect to their surface morphology and the chemical composition was screened by high-resolution XPS. The results demonstrate not only a significant, time-dependent influence of serum addition on the corrosion behavior of the materials studied, but noteworthy is that depending on the sample type, proteins in solution were observed to either accelerate or inhibit corrosion. These results are discussed in correlation to observed changes in surface chemistry taking place upon immersion in the absence and presence of proteins. Graphical abstract Unlabelled Image Highlights • Depending on the surface, proteins can accelerate/inhibit corrosion of a WE43 Mg alloy under simulated physiological conditions • High resolution XPS indicates adsorption of proteins to the surface of the Mg alloy • High level complexity of interfacial interactions for reactive biomaterials has been demonstrated in the presence of proteins [ABSTRACT FROM AUTHOR]

The results on the filling of styrene-acrylic polymer coatings with kaolin and wollastonite, including mechanically activated in a planetary ball mill, are considered for their main operational characteristics. It is shown that the use of mechanically activated wollastonite in an amount of 20–30 wt % allows one to improve a number of technological and operational characteristics of paint and varnish coatings, including adhesive ones. The use of standardized methods for determining the water and moisture absorption, opacity, and adhesion strength allowed us to indirectly evaluate the features of the formation of the structure of polymeric styrene-acrylic coatings. [ABSTRACT FROM AUTHOR]