Protective Polymer Coatings Research Articles

Микрокапсулирование ингибиторов коррозии и активных добавок для противокоррозионных защитных полимерных покрытий

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

Stearyl methacrylate co-polymers: Towards new polymer coatings for mortars protection

In the present work, a novel polymeric coating for mortars protection was prepared via free radical polymerization between methyl methacrylate (MMA) and stearyl methacrylate (STEA) to overcome the well-known technical problems related to the use of commercial Polyacrylic protectives. The physico-chemical properties of MMA_STEA and the effect of different STEA amounts (1.0-2.5-5.0% mol/mol respect to MMA) on MMA_STEA features were determined via 1H NMR and FT-IR spectroscopy, Gel Permeation Chromatography (GPC) and Differential Scanning Calorimetry (DSC). Furthermore, the long-term behavior of these polymeric protective agents was evaluated by means of accelerated aging tests exploiting UV radiations. MMA_STEA coatings were applied to air-hardening calcic lime mortars and their performances were studied using different surface techniques: static water contact angles (WCAs), CIELab colorimetric tests, water absorption by capillarity and water vapour permeability (WVP). All measurements were also performed after an UV aging test to study the durability of the coatings applied on mortar. This work demonstrates that a polymer coating prepared starting from methyl and stearyl methacrylates-based comonomers is an efficient way to obtain mortar protectives with satisfactory water repellent behavior, transparency and durability.

Microencapsulation of corrosion inhibitors and active additives for anticorrosive protective polymer coatings

Microencapsulation of corrosion inhibitors and active additives for anticorrosive protective polymer coatings

High‐Performance UV Protective Waterborne Polymer Coatings Based on Hybrid Graphene/Carbon Nanotube Radicals Scavenging Filler

AbstractUltraviolet (UV) degradation is one of the most important challenges of waterborne coatings in exterior applications. One of the ways to address this issue is addition of radical scavenging species within the polymer matrix. Herein, hybrids of graphene (G) and multiwall carbon nanotubes (CNTs) in different ratios are used as radical scavenging species. Evaluated by electron paramagnetic resonance spectroscopy, it is found that the hybrid made of G/CNTs in ratio of 10:1 efficiently captures and quenches the free radicals. The waterborne polymer composites containing 1 wt% of hybrid G/CNT are synthesized by in situ miniemulsion free radical polymerization using a water soluble initiator. However, due to excellent efficiency to capture free radicals, the polymerization performed using water soluble initiators in the presence of 10:1 G/CNT filler is hindered. This is resolved by physical separation of the free radicals and the scavenging materials within different phases by use of oil soluble initiator. The resulting polymer composites, beside having excellent mechanical resistance, present exceptional stability under accelerated aging conditions during 400 h, suppressing almost completely the UV photodegradation. This is attributed to the efficient radical scavenging of the G/CNTs hybrid filler distributed within polymer matrix, resulting in high‐performance UV protective waterborne composite coatings.

A review on protective polymeric coatings for marine applications

The main objective of this review is to discuss the recent research on polymer-based surface coatings contributing to the protection against marine biofouling based on the knowledge available in literature, supplemented by means of figures, mechanism illustrations, mathematical models, and equations. A need for studies on the mathematical behavior of such coatings is emphasized, composed of quantitative evaluation of foul-release performance of coatings using mathematical equations of the concerned parameters. Apart from the synthesis of protective polymeric coatings, understanding the relationship between characteristics of coating materials and accompanying foul-release and antifouling mechanism is important. In this regard, efforts have been made to equally evaluate, simulate, and measure the appropriate performance of the coatings. By examining the physicochemical and mechanical properties of the polymers, adhesion behavior has been found to be one of the prerequisites for the success of polymeric coatings for marine applications. The potential development of a broad spectrum of methods used to evaluate the foul-release performance of polymeric coatings depending on adhesion behavior of fouling organisms with the coatings has been discussed. From the analysis of the factors affecting degradation of coatings, environmental interference is declared a key factor for complete degradation of polymeric coatings. This review opens up new research directions to improve the adhesion performance of polymeric coatings for ship hulls designed with tunable viscoelasticity by the incorporation of elastomeric polymers (like polydimethylsiloxane) into stiff polymers (like epoxy resins) with and without the utilization of additives, modifiers, and nano-fillers. In addition, it provides methods to improve the foul-release performance of such coatings that work on adhesion behavior of biofouling species attached to the coating surface.

Investigation of Polymer Coatings Formed by Polyvinyl Alcohol and Silver Nanoparticles on Copper Surface in Acid Medium by Means of Deep Convolutional Neural Networks

In order to assemble effective protective coatings against corrosion, electrochemical techniques such as linear potentiometry and cyclic voltammetry were performed on a copper surface in 0.1 mol·L−1 HCl solution containing 0.1% polyvinyl alcohol (PVA) in the absence and presence of silver nanoparticles (nAg/PVA). A recent paradigm was used to distinguish the features of the coatings, that is, a deep convolutional neural network (CNN) was implemented to automatically and hierarchically extract the discriminative characteristics from the information given by optical microscopy images. In our study, the material surface morphology, controlled by the CNN without the interference of the human factor, was successfully conducted to extract the similarities/differences between unprotected and protected surfaces in order to establish the PVA and nAg/PVA performance to retard copper corrosion. The CNN results were confirmed by the classical investigation of copper behavior in hydrochloric acid solution in the absence and presence of polyvinyl alcohol and silver nanoparticles. The electrochemical measurements showed that the corrosion current density (icorr) decreased and polarization resistance (Rp) increased, with both PVA and nAg/PVA being effective inhibitors for copper corrosion in an acid environment, forming polymer protective coatings by adsorption on the metal surface. Furthermore, scanning electron microscopy (SEM) certifies the formation of polymer coatings, revealing a specific morphology of the copper surface in the presence of PVA and nAg/PVA, very different from that of corroded copper in uninhibited solutions. Finally, the correlation of the CNN information with experimental data was reported.

Thermal and spectroscopic studies of polymer protective coatings used in optical fibers technology

<p>An important factor determining the quality of optical fibers is their mechanical reliability. The control of the mechanical reliability allows define the lifetime of a fiber, which was under the stress during the work. Decisive influences on the mechanical and optical properties of the optical fibers have the protective coatings. Optical fiber technology requires that the coatings were applied on them on-line, directly after they have been drawn. So far, little attention has been paid to optimizing the conditions of coatings curing. In this work, the comparison of a thermoanalytical and spectroscopic analysis of coatings that were cured in an UV oven in which the power of the UV lamps was changed will be shown. As part of the research tasks, completed mechanical strength measurements were made with a silica fiber of 0.125 mm diameter.</p>

Novel Type II Bragg Grating Structures in Silica Fibers Using Femtosecond Lasers and Phase Masks

This review paper presents recent developments on the fabrication of novel thermally stable Type II fiber Bragg grating structures using femtosecond lasers and the phase mask technique. By manipulating the inscription beam and phase mask designs, exotic grating structures, such as ultrashort gratings <100 μm in length, Fabry-Perot structures or π-phase shifted structures can be created that are stable at high temperatures. These novel structures can also be created directly through protective polymer coatings such as polyimide, thus simplifying their manufacture.

Investigation of Protective Coatings for Bronze Using Combined Techniques

Bronze is a metal alloy that is commonly used for statuary, but also as decorative element in architecture. Naturally, the surface of bronze monuments tends to passivation and formation of patina. This acts as protection, but can also have a decorative value. Anyhow, in certain conditions an artificial protection of bronze sculptures is also desired. Waxes and polymeric protection (Incralac, Sotter, …), also in combinations of layers, are mostly used nowadays. However, in order to prepare more effective solutions for protection, there have been performed some studies on possibilities for application of organic coatings (benzotriazole [1,2]) and various polymeric protective coatings like acrylate/methacrylate [3], fluoropolymers [1], polyurethanes [4] and sol-gel [5,6]. Since conservators demand that the coatings have to be removable, sol-gel coatings are often overlooked. Various strippers, for example on the basis of benzyl alcohol, can be applied to remove polymeric coatings from bronze surfaces. From environmental point of view, the studies of polymeric coatings are not prepared only from solvent-born formulations, but are shifted also to water-born formulations and comparison of both types of coatings [3]. Herein is reported the investigation of fluoropolymer and polyurethane protective coatings for bronze. The characterization of these coatings was made by using different analytical techniques. For structural determination, infrared (IR) and Raman vibrational spectroscopies were applied. Surface characteristics were determined by scanning electron microscopy (SEM), atomic force microscopy (AFM) and contact angle measurements. Protective efficiency was analyzed using electrochemical techniques like potentiodynamic polarization and electrochemical impedance spectroscopy. As more advanced analytical techniques, there were applied ex situ IR reflection-absorption (IR RA) and in situ Raman spectroelectrochemistry. The analyzed coating is in both spectroelectrochemical techniques gradually chronocoulometrically charged at more and more positive anodic potentials to follow the eventual degradation processes that are analyzed spectroscopically after each charging. IR RA spectra are measured in near grazing incidence angle assembly using an angle of 80° and P polarized IR radiation. In such spectra longithudinal optical (LO) modes appear that are commonly shifted towards higher wavenumbers compared to usual transversal optical (TO) modes from absorbance IR spectra. The disadvantage is the contact of electrochemically treated protective coating with atmosphere. This circumstance is overcome in in situ Raman spectroelectrochemical technique. The coating on bronze is mounted in a custom-made Tephlon in situ three-electrode cell. The counter electrode is platinum grid and the reference electrode Ag/AgCl. All electrochemical experiments are performed in 0.5 M sodium chloride. Fluoropolymer coatings are prepared from resins on the basis of fluoroethylene/vinyl ether (FEVE) alternating copolymers (Asahi Glass Company, Japan). The building unit of FEVE compounds is -CF2-CFX-. Solvent- and water- born formulations are made from appropriate resins, by applying corresponding poly(isocyanate) hardener, defoamer, light stabilizers, surfactants and co-solvents. Results confirm that the higher contact angles for water are achieved for solvent-born coatings (> 100°) than for water-born coatings (< 80°). Potentiodynamic polarization measurements are in accordance with these values, suggesting higher protective effectivity of solvent-born coatings. The use of water-born coatings for outside long-term protection of bronze is questionable, since the ex situ IR RA measurements showed that after treatment at high anodic potential the coating becomes much thinner. Consequently, the band at 565 cm-1 appeared in the IR RA spectrum and can be assigned to Cu2O of the bronze substrate. Similarly, also the in situ Raman spectra showed that after application of long anodic chronocoulometric pulse the coating burned and detached from the bronze substrate. Solvent-born coatings reveal more stable behavior through in situ Raman spectroelectrochemical measurements. Solvent-born polyurethane protective coatings show hydrophobic properties and the contact angle of 110°. Relatively good protective properties are confirmed through potentiodynamic polarization curves, impedance spectroscopy and ex situ IR RA measurements. The latter technique shows quite stable response during forced degradation at high anodic potentials. The activity is carried out within the framework of the NANORESTART project which has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 646063.

Adaptive Polymeric Coatings with Self‐Reporting and Self‐Healing Dual Functions from Porous Core–Shell Nanostructures

AbstractIn biological system, early detection and treatment at the same moment is highly required. For synthetic materials, it is demanding to develop materials that possess self‐reporting of early damage and self‐healing simultaneously. This dual function is achieved in this work by introducing an intelligent pH‐responsive coatings based on poly(divinylbenzene)‐graft‐poly(divinylbenzene‐co‐methacrylic acid) (PDVB‐graft‐P(DVB‐co‐AA)) core–shell microspheres as smart components of the polymer coatings for corrosion protection. The key component, synthesized PDVB‐graft‐P(DVB‐co‐AA) core–shell microspheres are porous and pH responsive. The porosity allows for encapsulation of the corrosion inhibitor of benzotriazole and the fluorescent probe, coumarin. Both loading capacities can be up to about 15 wt%. The polymeric coatings doped with the synthesized microspheres can adapt immediately to the varied variation in pH value from the electrochemical corrosion reaction and release active molecules on demand onto the damaged cracks of the coatings on metal surfaces. It leads simultaneously to the dual functions of self‐healing and self‐reporting. The corrosion area can be self‐reported in 6 h, while the substrate can be protected at least for 1 month in 3.5 wt% NaCl solution. These pH‐responsive materials with self‐reporting and self‐healing dual functions are highly expected to have a bright future due to their smart, long‐lasting, recyclable, and multifunctional properties.

Влияние наноразмерных добавок на адгезионную способность защитных полимерных покрытий

Влияние наноразмерных добавок на адгезионную способность защитных полимерных покрытий

Protective features, durability and biodegration study of acrylic and methacrylic fluorinated polymer coatings for marble protection

Abstract In the present paper, a new fluorine based methacrylic monomer, 1H,1H,2H,2H-Perfluoro-octyl-methacrylate (POMA), was synthesized via esterification reaction from methacryloyl chloride and 1H,1H,2H,2H-Perfluoro-1-octanol. Furthermore, POMA was used to prepare with methyl methacrylate (MMA) via free radical polymerization a novel fluorinated methacrylic polymer (MMA_POMA), in order to overcome the well-known technical problems related to the use of acrylic monomer-based commercial protectives, such as Paraloid B72 ® . Indeed, in Paraloid B72 ® −obtainable from the copolymerization reaction of ethyl methacrylate (EMA) and methyl acrylate (MA)- the presence of an acrylic hydrogen atom in alpha to the carbonyl group can start photo-chemical degradation reactions that are able to promote fungi attack and proliferation. The properties of MMA_POMA and the two references synthesized, EMA_MA and EMA_MA_POMA −in terms of macromolecular structure, molecular weights, thermal features and water repellency- were determined; furthermore, the long-term behavior of these polymeric protective agents was estimated by means of accelerated aging tests exploiting UV radiations. Their behavior over time was checked via Size Exclusion Chromatography (SEC), Fourier Transform Infrared (FT-IR) spectroscopy and biodegradation assay. Lastly, MMA_POMA resin was applied on two marble substrates −Calcite and Dolomite- and its wetting properties were successfully assessed and compared to the same features displayed by the reference polymers. This work demonstrates that a polymer protective prepared starting from methacrylic and fluorinated monomers, i.e. MMA and POMA, is an efficient way to obtain resins with satisfactory water repellent properties and enhanced durability than acrylic based polymers without the use of any photo stabilizer additive.

A systematic study of the controlled generation of crystalline iron oxide nanoparticles on graphene using a chemical etching process.

Chemical vapor deposition (CVD) of carbon precursors employing a metal catalyst is a well-established method for synthesizing high-quality single-layer graphene. Yet the main challenge of the CVD process is the required transfer of a graphene layer from the substrate surface onto a chosen target substrate. This process is delicate and can severely degrade the quality of the transferred graphene. The protective polymer coatings typically used generate residues and contamination on the ultrathin graphene layer. In this work, we have developed a graphene transfer process which works without a coating and allows the transfer of graphene onto arbitrary substrates without the need for any additional post-processing. During the course of our transfer studies, we found that the etching process that is usually employed can lead to contamination of the graphene layer with the Faradaic etchant component FeCl3, resulting in the deposition of iron oxide FexOy nanoparticles on the graphene surface. We systematically analyzed the removal of the copper substrate layer and verified that crystalline iron oxide nanoparticles could be generated in controllable density on the graphene surface when this process is optimized. It was further confirmed that the FexOy particles on graphene are active in the catalytic growth of carbon nanotubes when employing a water-assisted CVD process.

Development of Anticorrosive Polymer Nanocomposite Coating for Corrosion Protection in Marine Environment

The marine environment is considered to be a highly aggressive environment for metal materials. Steels are the most common materials being used for shipbuilding. Corrosion is a major cause of structural deterioration in marine and offshore structures. Corrosion of carbon steel in marine environment becomes serious due to the highly corrosive nature of seawater with high salinity and microorganism. To protect metallic materials particularly steel against corrosion occurrence various organic and inorganic coatings are used. The most used are the polymeric protective coatings. The nanostructured TiO2 polymer coating is able to offer higher protection to steel against corrosion, and performed relatively better than other polymer coatings.

Mechanism of ionic conduction in multi-layer polymeric films studied via electrochemical measurement and theoretical modelling

Abstract Ionically permeable domains in polymeric protective coatings have been investigated empirically and theoretically. In the first part of the paper, results from recent experiments both complement and show agreement with received knowledge. This has allowed a physical model to be proposed for the mechanism of ionic conduction in polymeric coatings. This model assumes the random scattering of small regions with very different physical and chemical properties, akin almost to separate phase. Particularly the much higher rate of conduction is likely to have an impact on the coating’s anti-corrosion ability. Based on the superimposition of permeable and impermeable domains, the model can be applied to allow comparison of multi-layer systems with single coat films of the same thickness. Such a statistical model has practical corollaries and in the second part of the paper statistical methods are advanced to allow determination of the probability of having these permeable domains in two, three, four and more coats. This has been further refined by a virtual simulation process using the distribution of permeable domains on a two dimensional plane. The significance of the theoretical models is then discussed with respect to the experimental data and what they mean in terms of protective ability.

Protective adhesive zirconium oxide coatings

Modern technologies of application of paint or polymer protective coatings on metal surfaces require previous application of adhesive phosphate coatings on them to provide reliable adhesion. Among the known disadvantages of phosphating processes are their high energy content and the rather complex equipment needed for implementation of the processes, while the processes themselves require strict control because the properties of the resulting coatings depend strongly on parameters such as free and total acidity, temperature, and concentration of accelerators. In some cases, nanosized ceramic zirconium oxide adhesion coatings can be an alternative to adhesive phosphate layers. A solution has been prepared and parameters of the process have been determined allowing one to precipitate nanosized ceramic zirconium oxide coatings that satisfy the requirements for adhesive layers under paint coatings. It has been found that the resulting coatings are not inferior in their protective characteristics to amorphous phosphate and silicone coatings.

A review on conducting polymer coatings for corrosion protection

Corrosion of metals is one of the most important problems in the manufacturing industries. Many corrosion control methods use coatings of conducting polymers and conversion layers that contain toxic and environmentally hazardous materials, especially chromium compounds. These objectives have led to the development of new protective coating strategies that employs nanocomposites and carbon-based materials. In recent years, conducting polymers have attracted much attention because of their wide range of industrial applications and economic viability. Polymers possess long-chain carbon linkages and therefore, upon adsorption are able to block large areas of the corroding metal surfaces. The thin films adsorbed on the metal substrate provide a barrier effect between the metal and its environment. This review article summarizes the different techniques used in corrosion protection of metals, conducting polymers and nanomaterials, nanocomposites, and carbon-based materials in corrosion science.

Polymer Coatings for Protection of Wood and Wood-Based Materials

Three major types of protective coating of wood and wood-based materials have been considered. These three types include the coatings based on carboxyl-containing water-soluble polymers which are easily cross-linked by inorganic salts or OH-containing compounds, pH-sensitive coatings and polymer multi-layer structures. First of three mentioned approaches allows affecting permeability and enhancing the prevention the loss of water from the surface of wood to its surrounding. The advantage of the second approach is its ability to vary and purposely adjust the polymer composition and the number and distribution of -COOH groups in the chain which make the originally water-soluble polymers completely insoluble. The strong feature of the third approach which includes broad use of hydrogen-bonded films produced by layer-by-layer self-assembly is the possibility of manipulation of coatings stability after construction.

Protective Polymer Coatings for High-Throughput, High-Purity Cellular Isolation.

Cell-based therapies are emerging as the next frontier of medicine, offering a plausible path forward in the treatment of many devastating diseases. Critically, current methods for antigen positive cell sorting lack a high throughput method for delivering ultrahigh purity populations, prohibiting the application of some cell-based therapies to widespread diseases. Here we show the first use of targeted, protective polymer coatings on cells for the high speed enrichment of cells. Individual, antigen-positive cells are coated with a biocompatible hydrogel which protects the cells from a surfactant solution, while uncoated cells are immediately lysed. After lysis, the polymer coating is removed through orthogonal photochemistry, and the isolate has >50% yield of viable cells and these cells proliferate at rates comparable to control cells. Minority cell populations are enriched from erythrocyte-depleted blood to >99% purity, whereas the entire batch process requires 1 h and <$2000 in equipment. Batch scale-up is only contingent on irradiation area for the coating photopolymerization, as surfactant-based lysis can be easily achieved on any scale.

Modification of Bbituminous Coatings to Prevent Stress Corrosion Cracking of Carbon Steel

Stress corrosion cracking (SCC) is the most dangerous kind of pipelines corrosion. The SCC appears on the stressed metal due to contact with aggressive media through the rupture of polymer coating. Inhibition of the SCC is one of the urgent tasks of corrosion protection of underground pipelines. The research reports the method of inhibiting the SCC of pipe steels by modification of polymer protective coatings. With help of slow strain rate test (SSRT) the effect of general corrosion inhibitors and surfactants on the propensity X70 pipe steel to the SCC in aggressive electrolytes has been investigated. The vinyl-containing silane (VS) is shown to be an effective inhibitor of SCC of steel. The VS has been proposed as a modifying additive to a bitumen coating (DEKOM-GAZ type). Modification of coating should provide both satisfactory adhesion and exit of the SCC inhibiting compounds to electrolyte under film and their adsorption onto the metal surface in the case of mechanical damage or loss of adhesion. Peel shear test at an angle 90° away from steel plate has been used for evaluation of adhesive properties of modified coating. It has been shown that the additive of the VS does not impair the adhesion of the protective coating. Using FTIR microscopy output of the inhibitor molecules from the polymer matrix to solution and their adsorption onto the metal surface was evaluated. The aqueous extract obtained by exposure of the polymer coating with the addition of the VS in contact with water for 30 days has been investigated. IR-spectra analysis showed that predominantly the VS goes from the coating into solution and adsorbs on the metal surface. Thus the modified polymer coating, the use of which will prevent the development of SCC of carbon steel, has been developed.