Detection of different chemical binders in coatings using hyperspectral imaging

Organic coatings protect metallic structures of significant commercial value. Regular inspections of coatings are required to ensure their integrity and, therefore, to verify their stated performance. However, for metallic structures located in harsh places, coating inspection can pose significant safety and logistical challenges. Near-infrared (NIR) spectroscopy is a rapid, nondestructive and relatively inexpensive analytical technique. It is currently employed to analyze different chemicals in fields like agriculture, food, and pharmaceuticals. Similarly, hyperspectral imaging (HSI) creates a spatial map of spectral information by measuring light reflected from a material. In this work, hyperspectral imaging in the NIR portion of the electromagnetic spectrum (NIR-HSI) is used to accurately distinguish between the chemically different binders employed in commercial organic coatings. In addition, k-means clustering is explored as a tool to provide diagnostic information about the spatial inhomogeneities in the chemical structure of an applied coating, which, if undetected, can lead to coating defects during service life. The results of this work suggest that the NIR-HSI could be used for remote inspections of organic coatings.

Strategies for Preparation of Chiral Stationary Phases: Progress on Coating and Immobilization Methods

Enantioselective chromatography is one of the most used techniques for the separation and purification of enantiomers. The most important issue for a specific successful enantioseparation is the selection of the suitable chiral stationary phase (CSP). Different synthetic approaches have been applied for the preparation of CSPs, which embrace coating and immobilization methods. In addition to the classical and broadly applied coating and immobilization procedures, innovating strategies have been introduced recently. In this review, an overview of different methods for the preparation of coated and immobilized CSPs is described. Updated examples of CSPs associated with the various strategies are presented. Considering that after the preparation of a CSP its characterization is fundamental, the methods used for the characterization of all the described CSPs are emphasized.

About Determing the Microhardness of Composite Coatings

One of the fundamental tasks in restoring the operability of cylinder liners is the application of a composite coating with a predetermined microhardness value. The authors have developed a technology for applying composite coatings based on iron on cylindrical surfaces, which makes it possible to vary the physical, mechanical and operational parameters of the formed iron-containing coating due to the planned selection of the deposition parameters. This eliminates the need for mechanical treatment of the applied coating, which is the reason for the high degree of rejection parts that undergo the iron-on operation. Contact interaction of the working tool with the formed layer of the composite coating has a positive effect on the value of its roughness.

Comparative evaluation of the hardness of alloyed coatings from fastening CuSn—CrxCy mixture har dened by plasma and laser

The article is devoted to a comparative assessment of the possibility of increasing the wear resistance of the surface layer for steel St3 during plasma and laser heating of the applied surface coating of a mixture of CuSn—CrxCy alloys. It is shown that the fusion of a thin layer of a preliminarily applied coating of a CuSn—CrxCy mixture with a wide range of particle sizes is more suitable for plasma than for laser processing. It has been found that plasma coatings have a higher hardness and a lower probability of defects as compared to laser coatings. The results obtained can be used in the development of new technological processes for hardening machine parts and tools.

Application of Urea-Formaldehyde Oligomer for Quality Improvment of Paper and Cardboard Products

The applicability of the developed binary system of synthetic compounds in coating paste, consisting of urea-formaldehyde oligomer (2 pts. wt. to the coating paste weight) and latex (16 pts. wt.), is found. It replaces the generally used complex of natural compounds, such as modified starch (3 pts. wt.), Na-CMC (2 pts. wt.), and casein glue (1 pts. wt.), in the presence of latex (16–32 pts. wt.). The properties of the coating paste samples met the standards, as evidenced by the viscosity according to the viscometer VZ-4 (13–17 s), the content of dry substances (50–54 %) and pH (9.0–10.5). The proposed urea-formaldehyde oligomer is combined with the present components and, as compared to natural compounds, does not increase the viscosity of the coating paste, has a high cohesive force, participating in the binding of pigment particles with one another, has the necessary adhesive capacity for ensuring a stable bond of the applied coating layer with the surface of paper and cardboard, does not prevent the uniform distribution of pigment particles on the base surface, and gives stability to the coating paste. These phenomena can be explained by the supplementary presence of positively charged nitrogen-containing groups (amine and amide) in the ureaformaldehyde oligomer. The latter contribute to the enhancement of cohesive and adhesive interactions in coating pastes and coatings composed of them. Assessment of a section of the coated paper (cardboard) showed that one part of the binder adjoins the base (paper, cardboard) penetrating into its pores and capillaries, the other surrounds the pigment particles, and the third occupies (completely or partially) the spaces between the particles. An increase in the surface resistance to plucking and breaking length by 6.0–8.5 and 15–20 %, respectively, is shown on the samples of light-coated newsprint and polygraphic cardboard. This allows considering the urea-formaldehyde oligomer as an alternative to natural compounds. Herewith, whiteness (85–87 %) and smoothness (250–265 s) meet the requirements. Changing the formulation of the coating paste is economically justified, since material costs for the production of coated paper and cardboard products are reduced by 1–2 %.

The effects of fragranced microcapsules application on the physical and print quality characteristics of the prints

Today, various coatings are used in the printing industry, which give the printed product various additional features such as functional, decorative and protective properties. As a coating, fragrant microcapsules can be applied in combination with a printing ink or varnish to provide printed products with added value. The functionality of the applied fragranced microcapsules is initiated and achieved by rubbing the applied coating surface, whereby the microcapsules burst open and release the encapsulated active ingredient, the fragrance. In this paper the effects of the applied fragrance microcapsules (in the form of coating) on the print quality and the physical properties of the coated prints are investigated. Performed AFM and print quality analyses of the functional coatings produced showed that the applied fragrance microcapsules and their different concentrations significantly influence both the physical and print quality properties of the prints.

BIODEGRADABLE NONWOVEN ACTIVATED POLYESTER WITH CHITOSAN: POTENTIAL APPLICATION IN THE COSMETIC INDUSTRY

Textile products enriched with natural substances, e.g. hyaluronic acid, plant hydrolates, collagen and chitosan, may find wide application in cosmetics because of increasing consumer interest in natural products. Furthermore, in view of global environmental pollution, products that are produced through biochemical changes as a result of composting are sought. This makes it possible to enter such designed cosmetic products into the scheme of the currently desired circular economy. Compostable textiles are an ecological alternative to product backlogs and polluting the environment in the form of post-consumer waste. Therefore, this research work developed a technology for applying natural substances on a biodegradable polyester fibrous substrate. This study developed the optimal composition of a mixture consisting of natural substances with properties applicable to the cosmetic industry, for applications such as cosmetic masks to improve the appearance of the skin. The composition of active substances that have beneficial effects on the skin, e.g. moisturizing, regenerating, antibacterial and caring, was determined. The mixture was effectively applied on a spunbound nonwoven substrate of made from aliphatic-aromatic copolyester by impregnation. The employed polymer degraded in a compost environment and its modifiers additionally supported this process. The unique composition of the applied coating layer consisted of a mixture of sodium hyaluronate, collagen, bitter orange blossom hydrolate (Neroli) and chitosan lactate. The coated nonwoven fabric was subjected to physical, mechanical, microbiological as well as chemical purity and structural tests (Fourier transform infrared spectroscopy and scanning electron microscopy) and degree of degradation in a compost environment was assessed on the basis of its weight loss.

Enhanced Abrasion Resistance of Coated Particleboard Pre-Treated with Atmospheric Plasma

This study aims to investigate the influence of atmospheric plasma treatment on the abrasion resistance of particleboards, as an example of a wood-based material, coated with a waterborne finish. The treatment of the substrate, prior to coating application, using a floating-electrode dielectric barrier discharge (FE-DBD) plasma, resulted in an enhanced abrasion resistance of the coated particleboards in comparison to the untreated ones during the abrasion test with a duration of 200 revolutions. This finding was related to lower contact angles of water and coating after treatment with plasma and greater hardness of the coating on the treated substrates. The micrographs of the sample cross sections recorded with scanning electron microscope showed differences in the amounts of remained coating on the abraded areas. Investigation with attenuated total reflection Fourier transform infrared spectroscopy revealed that treatment of the substrate with plasma did not affect the chemical composition nor the curing and structure of the later applied coating. Further studies should be performed to determine the resistance properties of such surface systems to other impacts.

Painting for Aircraft

Objective This research is aimed to reduce time for the aircraft painting processes and decrease the budget for the painting activities which will not affect to the life limit of the painting and will not affect to the aerodynamic of the aircraft. method The research will be conducted by setting up the experiments to study the aircraft surface painting preparation methods, in order to find the better method of aircraft painting study the technical specification of the aircraft coating in associate with the viscosity of painting, air temperature for painting, relative humidity, drying time, lifetime period, hardness and difference, interval of time between painting and mixing solvent quality study the tools that use for painting such as air spray, airless spray, roller and brush study for error checking methods for understanding the painting defects result Reduce the errors that might occur during the aircraft painting processes which will lead to the budget decreasing and time reducing for aircraft painting conclusion To obtain the good quality of painting, it is very important to realize the specification of applied coating, working processes and painting equipment that associate with the maintenance manual of each aircraft, the effect factors that take into account of the painting and the technique of painting that is used.

Restoration and repair of equipment by supersonic cold gas-dynamic and micro-plasma spraying

The technological process of restoring and repairing of equipment and its components by supersonic cold gas-dynamic and micro-plasma spraying has been developed. For steel products Fe–Cr–Al-based composite powder has been used being surface reinforced with tungsten carbide particles. For nickel and titaniumproducts composite powder from an alloy of the Ni–Cr–Mn–Sn–Si–W–Re system (Ce, La, Y) has been applied being superficially reinforced by corundum nanopowder. During the work, a high hardness of the applied coating, corrosion resistance and wear resistance were achieved. Real examples of the successful restoration and repair by powder materials are given, and spraying technologies are proposed.