Varnish Coatings Research Articles

Thermophysical properties of light Polemer silicat shyngisite concrete in natural conditions

The development of methods for protecting the structures of external walls from corrosion under the influence of the aggressive production environment is an urgent task. The author has developed lightweight polymer silicate shungizite concrete (LPSC) for external walls of buildings with acidic humid gas environments. Exterior wall structures made of this material do not need to be protected by paint and varnish coatings. The properties of LPSC were investigated. The research results showed that the proposed material in its physical and mechanical properties meets the requirements for the material of outer walls. The material has been found to be highly corrosion resistant. Previously, the author presented the results of research of thermal conductivity of LPSC for exterior walls in laboratory conditions. The results of study of temperature and humidity conditions of the wall fragment of the proposed material in natural conditions are given in this article. The studies carried out confirmed the possibility of using the material proposed by the author for the outer walls of buildings with acidic humid-gas production environments.

Исследование влияния ультрафиолетового излучения на эксплуатационные свойства алкидных лакокрасочных покрытий марки ПФ-115

Представлены результаты исследования влияния ультрафиолетового излучения (207 нм) на коррозионную стойкость, твердость и адгезию алкидных лакокрасочных покрытий. Установлено, что облучение лакокрасочных материалов в процессе их отверждения не оказывает существенного влияния на концентрацию элементов. Исследования коррозионной стойкости покрытий методом полярографических кривых в насыщенном растворе хлорида натрия показали, что облучение ультрафиолетовым излучением алкидных лакокрасочных покрытий в процессе отверждения приводит к повышению их коррозионной стойкости к агрессивным средам вследствие увеличения сплошности и гладкости. Показано, что адгезия облучаемых лакокрасочных покрытий не ухудшается, сохраняя свое максимально возможно значение. Обнаружено, что увеличение длительности облучения способствует увеличению коррозионной стойкости и твердости покрытий.

Evaluation and comparison of the apical seal obtained with Biodentine after conditioning of root end with three different solutions using ultraviolet-visible spectrophotometer: An in vitro study

Aim: The aim of the study is to evaluate and compare the apical seal obtained with Biodentine after conditioning of root end with three different solutions (HEBP, chitosan, and ethylenediaminetetraacetic acid [EDTA]). Materials and Method: Forty-eight maxillary incisors were selected and decoronated. Instrumentation was done with protaper rotary files up to F4 file and obturated with AH plus sealer (Dentsply, Germany) and Protaper gutta-percha cone using lateral condensation technique. The apical part of each root was resected at 90° to the long axis of the root for 3 mm, and retrograde cavity preparation was done in standardized dimensions. The teeth were randomly divided into four groups with 12 samples in each group and later subjected to a standard regimen of 3 ml of respective solutions for 5 min: Group I – 18% HEBP, Group II – 0.2% chitosan, Group III – 17% EDTA, Group IV – saline (control). All teeth were then restored with Biodentine (Septodont, USA). Samples were coated with two coats of nail varnish except in the apical 3 mm which will be immersed in 5 ml of 2% methylene blue dye and stored in incubator for 72 h. The nail varnish will be removed later, and the teeth will be immersed in 35% nitric acid for 72 h. The solutions were then filtered using a fine-grit filter paper and centrifuged at 2000 rpm for 1 min. The solutions thus collected will be used to determine absorbency in ultraviolet-visible spectrophotometer. Results: The mean values of absorbance were greatest for Group IV (saline) followed by Group III (17% EDTA), Group II (0.2% chitosan), and Group I (18% HEBP). Group IV (saline) and Group III (17% EDTA) have got statistically significant difference with all the other groups. Group II has got statistically significant difference with all the other groups except Group I. Conclusion: Within the limitations of the study, it was concluded that irrigation with newer agents significantly influenced the sealing ability of biodentine. Root-end irrigation with 18% HEBP and 0.2% chitosan showed the least microleakage when compared to 17% EDTA.

Исследование современных лакокрасочных покрытий автомобилей производства фирм «УАЗ» и «Volkswagen»

The article presents the results of a study of samples of factory paint and varnish coatings of cars of the "UAZ" and "Volkswagen" model series in accordance with the methods of studying paint and varnish coatings of vehicles in force in the system of forensic departments of the Ministry of Internal Affairs of Russia. When carrying out the study, a set of recommended methods for studying paint and varnish coatings was used - optical microscopy, infrared spectroscopy, electron scanning microscopy with X-ray spectral microanalysis. In the course of the work, the morphological features of the investigated each layer of the studied paint and varnish coatings were determined, and the infrared spectra of these layers were also recorded and interpreted. Based on the analysis of infrared spectra, the qualitative molecular composition of the main components of soils, enamels and varnishes of paint and varnish coatings was determined. Electronic images of cross-sections of paint-and-lacquer coatings of UAZ and Volkswagen vehicles were obtained, as well as X-ray spectra of each layer. The data obtained made it possible to generalize and compare the characteristic features of paint and varnish coatings of each manufacturer. So, for paint and varnish coatings manufactured by Volkswagen, the following characteristics have been determined: the first primers of the samples are made on the basis of a polyester binder containing titanium dioxide in the mineral part, the second primers (fillers) are made on the basis of an acryl-urethane or polyacrylate binder with various modifiers, containing barium sulfate, titanium dioxide and other fillers, the lacquer layers are made on the basis of an acrylic-urethane binder modified with styrene and melamine. The paint and varnish coatings produced by "UAZ" were characterized by the following features: the first primers were made on the basis of an epoxy-ester binder containing various fillers. In the manufacture of the second primers (fillers), an alkyd binder modified with melamine can be used. The available lacquer layers are made on the basis of a polyacrylate binder modified with styrene and melamine. The identified groups of features make it possible to differentiate the paint and varnish coatings of cars of the UAZ and Volkswagen model lines within the framework of the examination of materials, substances and products.

Technology for fixing mine workings with friction anchors of the SZA type with a new type of anticorrosive coating

The issues of ensuring the stability of mine workings in weak rocks due to the use of combined roof support based on anchors with a new type of anti-corrosion coating on the example of mining enterprises of the Russian Federation are considered. As a result of the work, the quality indicators of man-made mine waters of mining enterprises of the Russian Federation were determined, the conditions of the mine atmosphere that contribute to the intensification of metal corrosion were identified, an experiment was conducted in the research laboratory to determine the corrosion resistance of self-fixing anchors, the most suitable anchor coatings for their use in aggressive mine environments were identified, The technology of fixing with anchors with a new type of anti-corrosion coating is proposed. Also shown are the conditions for the use of galvanized, paint and varnish coatings, as well as various protective materials, the scope of their application, the advantages, and disadvantages of these coatings in mine environments are indicated. The prospects for the use of new types of coating are shown and directions for further research in this direction are indicated.

Разработка кремнийорганического декоративного покрытия с кракелюр эффектом

The article analyzes coatings based on organosilicon compounds and presents the results of research on the selection components of compositions that provide protection of painted products from corrosive environments, mechanical and thermal effects. Defects of paint and varnish coatings are investigated. The expediency of modifying organosilicon film-forming compositions with solutions bead polymers of polymethyl methacrylate and polybutyl methacrylate has been substantiated. To obtain a heat-resistant coating, two compositions were developed for the lower and upper layers. The bottom layer was KO-85 organosilicon varnish modified with solutions of bead polymers and PF-060 alkyd varnish. To regulate the wetting and spreading, surfactants were introduced into the bottom layer, which could improve the structural, mechanical and decorative properties of the coatings. The top layer of the coating with the craquelure effect was KO-868 silicone enamel modified with functional additives that increase the surface tension and reduce the spreadability of the resulting composition. Research has been carried out on the physica-mechanical (adhesion, impact strength, elasticity of the film during bending), decorative (change in gloss, color, dirt retention, chalking) and protective (cracking, peeling, weathering, bubble formation, corrosion of metaln, wrinkling, dissolution) properties of a two-layer coating, as well as its resistance to water, gasoline, mineral oil and temperature.

Cutting forces during drilling and selected physical and mechanical properties of the finish coating based on epoxy resin

Abstract: Cutting forces during drilling and selected physical and mechanical properties of the finish coating based on epoxy resin. Paper presents selected tests of epoxy resin coating applied to American walnut wood (Juglans nigra L.). The aim of the study was to assess the machinability of wood flooded with resin during drilling. The axial forces and torque values were adopted for the machinability criteria. The idea of the research was the thesis questioning the possibility of processing epoxy resin coatings with the application of tools and parameters used during wood processing. In addition, the influence of UV light on the obtained coating was examined and abrasion tests were carried out. It was found the resin changes its colour under the influence of UV radiation, but the change is imperceptible to an average observer. Epoxy resin is characterized by low abrasion resistance compared to commonly used paint and varnish coatings. Although solid resin is characterized by high cutting resistance while drilling, the force values do not exceed the commonly cut wood-based materials.

Study of Heat Resistant Urethane Varnish Coatings Based on Isocyanate-Containing Prepolymers and Dicyandiamide

The structure and properties of urethane varnish coatings based on isocyanate-containing prepolymers are studied using the methods of atomic force microscopy, thermomechanical analysis, differential scanning calorimetry, and dynamic mechanical analysis. By the modification of isocyanate-containing prepolymers with dicyandiamide, the possibility of producing urethane varnish coatings having different supramolecular structure, high thermal and operational properties is shown.

Effects of heat treatment systems on the physical properties of coated Scots pine (Pinus sylvestris L.) and poplar (Populus euramericana)

Heat treatment is an environmentally friendly and efficient way to improve the properties of wood species. These treatments alter the substrates and can influence the surface properties of the varnish coatings. This paper investigated the effects of heat treatment on the physical properties of open and close systems Scots pine (Pinus sylvestris L.) and poplar (Populus euramericana) wood, coated with water-based, polyurethane-based, and oil/wax-based varnishes. Heat treatment was applied at the temperatures of 190, 212 °C for pine and 180, 200 °C for poplar, respectively. Color, gloss, and roughness tests were carried out for each of the coatings. Higher mass loss occurred in pine samples with heat treatment as compared to vacuum-heat treatment. Gloss decreased in OIL+WAX treatment and color change increased after the heat treatment, but these results were inhibited with vacuum-heat treatment. Maximum roughness was obtained in PUR varnishes and minimum roughness in OIL + WAX samples. The low roughness values provide some advantages in application.

Spectrophotometric analysis evaluating apical microleakage in retrograde filling using GIC, MTA and biodentine: an in-vitro study

BackgroundThe present study compares the apical microleakage of three different root-end filling materials in which the retrograde cavity is prepared by two different burs.MethodsEighty extracted single rooted maxillary and mandibular premolars were taken. Root canal treatment was completed. Apical 3 mm of all the teeth were resected with diamond disk. The tooth were divided into four groups with two subgroups for each group containing 10 tooth (N = 10) as: Group IA (Negative Control and IB (Positive Control); Group IIA and IIB: Prepared with round carbide bur and round diamond bur respectively, filled with GIC; Group IIIA and IIIB: Prepared with round carbide bur and round diamond bur respectively, filled with MTA; Group IVA and IVB: Prepared with round carbide bur and round diamond bur, filled with Biodentine. After applying two coats of nail varnish leaving apical 3 mm (except for negative control group) all teeth were immersed in 2% methylene blue for 3 days and again in 65% nitric acid for next 3 days for extraction of dye. The obtained solution was then transferred to eppendorf tube and centrifuged in microcentrifuges at 14,000 revolution per minutes (RPM) for 5 min. Optical density or absorbance of the supernatant solution was measured with UV spectrophotometer at 550 nm.ResultsThe absorbance of the supernatant solution after dye extraction is decreasing in the order of positive control> GIC > MTA > Biodentine> negative control group. The significant difference was observed between GIC and MTA (p = 0.0001) and GIC and Biodentine (p = 0.0001) with two different burs but statistically non-significant difference was observed between MTA and Biodentine with Carbide bur (p = 0.127) and Diamond bur (p = 0.496) respectively.ConclusionsWithin the limitations of the present study, it can be concluded that Biodentine and MTA showed less microleakage as compared to GIC. There is no significant difference between mean microleakage of MTA and Biodentine. However, the mean OD of the Biodentine was least of all evaluated materials. Preparation of the root-end using round carbide bur as well as round diamond burs showed comparable microleakage for all three filling materials.

Microbiological corrosion of building materials

The research results in the field of microbiological corrosion of building materials of domestic and foreign experts are presented. It is shown that microorganisms cause corrosion of concrete on cement and other binding metal and other materials. Metals in the order of decreasing the rate of biocorrosion are arranged in the following row: aluminum, mild steel, zinc, brass, copper, stainless steel. Concrete, due to its high surface activity, is capable of adsorbing a wide variety of substances, including microorganisms: bacteria and mycelial fungi. Among bacteria, nitrifying agents, thionic, iron and silicate bacteria and others participate in the corrosion of cement concrete (mainly due to their acid secretions). According to the data of a number of authors, on the surface of stone building materials mycelial fungi of the genera Penicillium, Aspergillus, Trichoderma, Cephalosporium prevail. Biodeterioration in this case mainly comes down to the disruption of cohesion of constituent components as a result of exposure to mineral or organic acids, as well as enzymes and due to chemical reactions between the cement stone of solutions and concretes and the waste products of microorganisms. The compositions of bituminous composites at various ratios of the materials used without inclusion in the composition of fungicides showed non-fungal resistance and non-fungicide. Comparison of concrete on gypsum and phosphogypsum binders showed that samples on a phosphogypsum binder overgrow microorganisms somewhat more, wood materials are subject to significant biodeterioration at high humidity. Biodegradation of wood occurs mainly due to the use of mushrooms as food sources of cellulose, lignin and other components. Synthetic polymers and materials based on them are significantly superior to natural polymers in biostability. However, under certain operating conditions, they are damaged by biological agents. Biological damage to plastics, as well as other materials, occurs simultaneously with their aging under the influence of external physical and chemical factors (ultraviolet radiation, water, temperature changes, etc.). Additives that are usually always present in polymer compositions (fillers, plasticizers, stabilizers, antioxidants, modifiers, pigments, etc.) significantly affect the biostability of polymeric materials. One of the effective ways to increase the biostability of composite building materials is the introduction of fungicidal additives in their composition. It is also shown that of great importance in increasing the durability and increasing the life of some building structures (metal products, communications, underground pipelines and some others) is their protection by paint and varnish coatings.

A non-invasive screening study of varnishes applied to three paintings by Edvard Munch using portable diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS)

The availability and popularity of portable non-invasive instrumentation for the study of paintings has increased due to a shift away from using micro-invasive techniques. Fourier transform infrared spectroscopy (FTIR) is a successful and established technique for the characterisation of organic materials in varnish coatings and paint films. In addition, portable FTIR (pFTIR) spectrometers allow for non-invasive in situ analyses. This overcomes the disadvantages associated with micro-sampling and reproducibility issues encountered in analysis at a specific spot, as pFTIR enables examination of the whole painting. However, the practical applications and capabilities of pFTIR as a suitable screening method for the chemical characterization of varnish coatings in painting collections require systematic evaluation. This study involves a selection of three paintings from the collection of 57 works by Edvard Munch belonging to The National Museum of Art in Norway. Its focus is the identification of the non-original varnish types that were applied by the museum. Between 1909 and 1993, the Museum was embroiled in a varnish controversy due to their application of, first natural and then synthetic, varnish coatings to 48 of these Munch paintings. A series of public debates arose about the Museum’s varnishing practice, which ran counter to the artist’s usual custom of leaving paint surfaces unvarnished (or occasional locally varnished). The three paintings were screened using a pFTIR spectrometer. Different regions of the varnished and unvarnished painted surfaces were analysed with Portable Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). These paintings date from 1887 to 1891 and are documented as having been treated at the Museum with one of the following types of natural or low-molecular-weight synthetic varnish coatings: dammar, mastic, polycyclohexanone (Laropal K 80 from BASF) and reduced or hydrogenated cyclohexanone-co-methyl-cyclohexanone (MS2A from Howards of Ilford). Surface microscopy and multispectral imaging of the varnished surfaces initially assisted the mapping and choice of areas relevant for the portable DRIFTS measurements. Portable X-Ray fluorescence and surface gloss readings were also made at the pFTIR spot locations to complement the results. Using known dry varnish samples, pFTIR reference spectra were obtained and a DRIFT spectral library was also created from known historic batches of varnishes used by the museum. These were then compared with the in situ pFTIR surface readings taken from the paintings together with additional spectra acquired from a selected number of micro-samples from the same spot locations. The preliminary measurements provided an insight into the capabilities, limitations and practical aspects of using portable DRIFTS for the identification of varnish coatings present in this specific selection of Munch paintings.

The Effect of the Mechanical Activation of Silicate Nature Fillers on the Properties of Styrene—Acrylic Polymer Coatings

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.

Self-Healing Paint and Varnish Polymer Coatings

The literature, patent, and authors’ data on procedures for preparing self-healing polymer paint and varnish coatings are summarized. “External” and “internal” routes of preparing such coatings, in particular, microencapsulation technologies and procedures based on specific rheological properties of polymers, are analyzed in detail. It is concluded that the efficiency of the encapsulation method for preparing coatings is low. Prospects for using polyurethane and thermoplastic film-forming agents for preparing self-healing polymer paint and varnish coatings are demonstrated.

Multi technique and multiscale approaches to the study of ancient and modern art objects on wooden and canvas support

Abstract The present chapter will illustrate few examples of multi-technique and multi-scale approaches for objects belonging to past or modern periods in the history of art chronology. Thus, four studies on four different topics are brought to the attention: multi disciplinary and multi-techniques characterization of gilded altarpieces and sculptures in Portugal between 1500 and 1800 (3 years research project); an interdisciplinary approach to easel paintings from fifteenth and sixteenth century in Portugal (3 years research project); characterization of ketone resins varnishes (2 years research project) and of salts developed on canvas paintings from the Munch Museum collection (past investigation to be continued with an ongong 3 years research project). These studies show how important is to make use of different analytical tools when investigating a specific material, artistic technique or degradation phenomenon. The objects studied in the above mentioned research projects were created on wooden or canvas supports and they present paint, polichromy or gilded layers, and varnish coatings, therefore their structure and composition is complex and requires a complex, interdisciplinary approach. In many cases to the surface materials from a polychrome or painted object, degradation products are present and their identification as well the understanding of their mechanism of formation is possible only we have a complete overview of the materials present in the layered structure of the object.

Three dominating hypocrealean fungi of the ‘white mold spots’ on acrylic varnish coatings of the murals in a Koguryo tomb in China

Acrylic varnish B01-6 is extensively applied to protect exquisite wall paintings of Wu-Kui Tomb by spraying on the murals to form a hyaline membrane avoiding the color fading and deterioration. However, serious ‘white moldy spots’ are observed on the B01-6 coatings area on the murals seasonally. Culture-dependent and culture-independent approaches reveal that the fungal community of ‘white moldy spots’ is dominated by three hypocrealean fungal taxa. Evidence for these species is provided by morphological comparison and phylogenetic analysis of LSU and ITS sequence data. Two known taxa, namely, Acremonium camptosporum and Sarocladium kiliense, are identified. One novel taxon, Leptobacillium muralicola is also described and compared with other Leptobacillium species. Leptobacillium muralicola can be distinguished from other Leptobacillium species by the colonial color changes from greyish white to greenish white over time, and less ratio of conidial length/width.

Visuo-tactile and topographic characterizations of finished wood surface quality by French consumers and industrials: acceptability thresholds for raised grain

Context: Raised grain occurs on wood surfaces after the application of a waterborne varnish and forces manufacturers to sand the surfaces between coats. Actually, little research has characterised this phenomenon and no techniques have been discovered to avoid its occurrence. Aims: This study aims to identify the topographic parameters that explain the visuo-tactile sensation of raised grain and to define a finished surface quality acceptable to consumers and industry. Methods: Oak (Quercus robur L.) and beech (Fagus sylvatica L.) wood surfaces were planed and sanded in order to have various levels of raised grain. Visuo-tactile analyses were carried out on surfaces having received one coat of varnish to characterise raised grain and having two coats to characterise the acceptable finished surface quality without sanding. Topographic parameters were measured on each type of varnished surface and correlated with the visuo-tactile scores. Results: Raised grain was characterised by the visuo-tactile sensation of protruding peaks and a certain amount of material in the core of the roughness profile for both wood species. Industrials overestimated the surface quality required by consumers. Thresholds of topographic parameters were determined to define acceptable finished surface quality. Conclusion: These findings allowed objective criteria to be defined for describing raised grain and to help industries to optimise their wood machining and finishing processes.

Биоповреждения лакокрасочных покрытий и способы защиты

Аbstract: the article discusses the issues related to the protection of paintwork materials from biological damage. Paint and varnish materials and coatings are exposed to damage caused by various microorganisms during operation, since many components of the materials are used by microbes as power sources. The greatest destruction is caused by bacteria and microscopic fungi. At the moment there are practically no absolutely biostable paints and coatings. Depending on their chemical composition and structure, we can only talk about compositions that are more or less resistant to biological damage. One of the effective ways to protect materials from biological damage is the introduction of various biocidal additives into their composition.

Durability of Paint and Varnish Coatings Depending on the Quality of their Appearance

The aim of the work is to study the regularities of the influence of the quality of the appearance of coatings on their durability during the operation. Object of research - paint and varnish coatings of building products and construction. Information on the effect on the longevity of coatings of the quality of their appearance is given. It is shown, that coatings with a high roughness index are characterized by low durability during exploitation. Are revealed the influence of the rheological properties of the paint, the porosity of the substrate on the surface roughness of the coatings. Determined, that regardless of the type of paint composition, the strength and relative deformations are reduced, the plastic deformation is increased and the elastic deformation are reduced with increasing roughness of surfaces. A mathematical model is obtained of the dependence of the tensile strength on the roughness of the surface of the films. It is established, that during the moistening of the coatings in the first stage (up to 30 days), the roughness of the surface is reduced, i.e., the surface micro relief is levelled due to the plasticizing effect of moisture (swelling of the coatings). In the future, due to the destructive effect of moisture, the surface roughness increases, caused by the appearance of micro cracks, rashes, and bubbles. It is established, that in the process of cyclic freezing-thawing the cracks appear locally and are formed near defects on the surface of the coating. The researches allow to develop recommendations for increasing the resistance of coatings and to select the optimum rheological properties of paints depending on the porosity of the substrate.

Development of model of the quality of the appearance of paint and varnish coatings

The regularities of the formation of the quality of the appearance of coatings from the rheological and technological properties of colorful compositions are established. It was revealed that with an increase in the surface tension of paint , a lower quality of the appearance of the resulting coating is observed. With an increase in the porosity of the substrate, an increase in the surface roughness of the coatings is observed. A model of the appearance quality of coatings is proposed depending on the porosity of the substrate and the surface tension of the paint composition