Search Results (38)

Microplastic pollution of ecosystems is considered a modern problem. Freshwater ecosystems, despite the interest shown in their study, remain poorly understood. Lake Baikal (Russia) is one of the least studied freshwater ecosystems in this regard. This large lake is distinguished from others by its high level of biodiversity and clean drinking water. The aim of this study is a multi-matrix investigation of microplastic pollution in one of the lake’s bay. The following matrices are used: surface water, water column, sediment, macrophytes, macroinvertebrates, and fish, as well as ice and snow during the winter. The results show that certain locations exhibit high concentrations of microplastic particles. In some cases, this was due to the properties or characteristics of these locations (littoral zones near the water’s edge, macrophytes with mucus sheaths, ice and snow (potentially, the near-surface water layer after ice melt)), while in others, it was due to localized pollution (pier and ship mooring areas). An analysis of the polymer types of the detected microplastic particles reveals the presence of both common (polypropylene, polyethylene terephthalate, polystyrene, polyethylene, polyvinyl chloride) and rare (polyvinyl alcohol and alkyd resin). Moreover, in some locations, the latter two polymers predominate, a phenomenon rarely observed in other studies. Further research was recommended to focus on the chronic effects of microplastic particles on organisms associated with areas of elevated particle concentrations. Full article

Two folding screens by futurist artist Giacomo Balla (1871–1958) in the collection of the Kröller-Müller Museum (the Netherlands) were investigated: Paravento con linea di velocità (1916–1917) and Paravento (1916/1917–1958). The screens are painted on both sides, the first on four canvases, stretched onto two wooden strainers and framed with painted wooden strips, and the second on wooden panels set into four painted stiles. In the past, damages on Paravento con linea di velocità were restored by conservators, while Paravento was probably first reworked by the artist himself and later restored by conservators. Yellowed varnish and discolored retouches on both screens led to a wish for treatment. The aim of this research was to gain insight into the painting techniques, layer buildup, pigments, binders, and varnishes of the two artworks. This information supported the decision making for treatment, and it broadens the knowledge on the materials used by Balla. Up to now, only a few published studies deal with the technical examination of paintings by this artist. Both folding screens were subjected to technical photography (UV, IR photography, and X-ray) and were examined with portable point X-ray fluorescence (pXRF) and Raman spectroscopy. Moreover, samples were taken. Cross-sections were studied with optical microscopy, scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), attenuated total reflection Fourier-transform infrared (ATR-FTIR) imaging, and micro-Raman spectroscopy. Loose samples were examined with SEM-EDX, FTIR and micro-Raman spectroscopy, and pyrolysis gas chromatography mass spectrometry (Py-GC/MS). For Paravento con linea di velocità, all pigments and fillers of the painted canvases are compatible with the dating of the screen (1916–1917), but they differ from those on the frame. Here, rutile, in combination with various pigments, among which are blue copper phthalocyanine (PB15) and other synthetic organic pigments, was found. This indicates that the frame has been painted later, likely after the Second World War. The composition of the binders differs as well. Drying oil and pine resin have been used on the canvases, explaining the smooth and glossy appearance and solvent-sensitivity of the paint. On the frame, oil with some alkyd resin was identified. The provenance of the screen before 1972 is not clear, nor when the frame was made and painted and by whom. The results for Paravento indicate that the palettes of the two sides—painted in different styles—are comparable. Mainly inorganic pigments were found, except for the dark red areas, where toluidine red (PR3) is present. pXRF showed high amounts of zinc; cross-sections revealed that zinc white is present in the lower layers. These pigments are compatible with the dating of the screen (1916–1917). In many of the upper paint layers though, except for some green, dark red, and black areas, rutile has been identified. This indicates that these layers were applied later, likely after the Second World War. Since this folding screen was used by the artist and his family until his death in 1958, it seems likely that Balla himself reworked the screen. Full article

In response to environmental concerns and the depletion of fossil resources, transitioning coatings toward sustainability is imperative. Bio-based coatings, derived from renewable biomass, represent a highly promising development pathway. This review comprehensively summarizes recent advances, prevailing challenges, and future prospects of bio-based coatings, with a focus on bio-based polymer resins—serving as the primary film-forming materials—and key auxiliary components such as pigments and fillers, additives, and solvents. This review systematically elaborates on the definition of bio-based coatings, their raw material sources, and international standards for bio-based carbon content determination. The core strategies for converting biomass into coating components are critically analyzed, namely direct utilization, physical blending, chemical modification, and biosynthesis. Furthermore, the synthesis, properties, and applications of key bio-based polymer systems—including epoxy, polyurethane, alkyd, and acrylic resins—are critically discussed, with particular emphasis on how molecular engineering enhances their performance and functionality. Despite significant progress, bio-based coatings still face several challenges, such as balancing performance and cost, ensuring the stability of raw material supply chains, and establishing globally unified standards. This review concludes that the integration of chemical modification and biosynthesis technologies, coupled with the establishment of a unified bio-based content standard system, constitutes two core drivers for advancing bio-based coatings from “green alternatives” toward “high-performance dominance” in the future. Full article

Alkyd resins (ARs) represent a significant development in synthetic polymers, being among the oldest ones and playing a crucial role in numerous applications, especially within the coating sector. The trend is moving towards replacing non-renewable resources in the production of ARs with bio-based alternatives, with the goal of creating more sustainable binder materials as part of the transition to a bioeconomy. 2,5-Furandicarboxylic acid (FDCA) serves as a promising biomass-derived “building block” to replace non-renewable petroleum-derived aromatic diacids and anhydrides in AR synthesis. Various vegetable oils, including sunflower seed (SFO) and linseed oils (LSO), were utilized along with pentaerythritol (P) and glycerol (G) as polyols. FTIR and ¹H NMR spectroscopies were conducted for the verification of alkyd structures. The synthesized ARs were assessed for their physico-chemical properties, including acid value, hydroxyl value, color, density, and viscosity. The performance of the resulting alkyd coatings, which are crucial for their commercial applications, was examined. Key factors such as drying time, hardness, adhesion, wettability, chemical and corrosion resistance, and UV stability were analyzed. All synthesized FDCA-based alkyd coatings demonstrate outstanding adhesion, good thermal stability up to 220 °C, and barrier properties for steel with |Z|_0.02Hz ~10⁶–10⁷ Ohm cm⁻², which render them suitable for the processing requirements of indoor coating applications. The higher temperature at 50% mass loss (T₅₀) for SFO-P (397 °C) and LSO-P (413 °C) as compared to SFO-G (380 °C) and LSO-G (394 °C) indicated greater resistance to thermal breakdown when pentaerythritol was used as a polyol. Replacing glycerol with pentaerythritol in FDCA-based ARs resulted in a viscosity increase of 1.2–2.4 times and an enhancement in hardness from 2H to 3H. FDCA-based ARs exhibited decreased tack-free time, enhanced thermomechanical properties, and similar hardness as compared to phthalic anhydride-based ARs, underscoring the potential of FDCA as a sustainable alternative to phthalic anhydride in the formulation of ARs, integrating a greater proportion of renewable components for wood coating applications. Full article

Most studies on microplastic pollution in aquatic ecosystems have focused on the quantitative and qualitative assessment of particles in surface waters. However, the highest concentrations and accumulation of microplastic particles are observed in bottom sediments. The aim of this study was to determine the concentrations of microplastic particles of different morphology in sediments in the beach and littoral zones of Lake Baikal. This study is the first in relation to Lake Baikal to focus specifically on the analysis of microplastic particles in bottom sediments. The results of the study showed that the registered values of concentration of microplastic particles do not exceed the average values for lakes around the world. The predominant type of particles in both the littoral zone and the beach is microplastic fibers. An exception is observed only for one of the locations. This exception is related to the permanent mooring of vessels in this place. Analysis of the types of artificial polymers showed that the microplastic fibers were represented by polyester, and the fragments were represented by alkyd resin (66%), polyvinyl alcohol (32%) and polyvinyl chloride (2%). Shown for the first time in this study, the presence of large numbers of microplastic particles with rare types of artificial polymers suggests that these particles may be under-reported in other studies. The underestimation of particles may be due either to the selection of sampling locations located far from heavily contaminated areas, or to the fragility of these polymers. Although the harm of these types of polymers has not yet been confirmed, the large number of these particles in local areas of lakes should be taken into account. This is due to the large number of organisms, which is usually characteristic of littoral areas, including Lake Baikal, with its diversity of fauna and flora. Full article

Alkyd resins are among the most common coatings used for exterior wood joinery. In Romania, solvent-borne alkyd coatings are widely used to finish wood. The study aims to compare the performance after 7 years of outdoor exposure of two types of alkyd coatings, a semi-transparent brown stain with micronized pigments (Alk1) and an opaque white enamel (Alk2), applied directly on wood or wood pre-treated with three types of resins: acryl-polyurethane (R1), epoxy (R2), and alkyd-polyurethane (R3). Fir (Abies alba) wood served as the substrate. Cracking, coating adhesion, and biological degradation were periodically assessed through visual inspection and microscopy. Additionally, a cross-cut test was performed, and the loss of coating on the directly exposed upper faces was measured using ImageJ. The results indicated that resin pretreatments somewhat reduced cracking but negatively affected coating adhesion after long-term exposure. All samples pretreated with resins and coated with Alk1 lost more than 50% (up to 78%) of the original finishing film by the end of the test. In comparison, coated control samples lost less than 50%. The Alk2 coating exhibited a film loss between 2% and 12%, compared to an average loss of 9% for the coated control. Overall, samples pretreated with alkyd-polyurethane resin (R3) and coated with alkyd enamel (Alk2) demonstrated the best performance in terms of cracking, adhesion, and discoloration. Full article

This study focuses on the nameplate of Vila D. Bosco, a modern building in Macau from the time of Portuguese rule, and looks at the types of metal materials and surface coatings used, as well as how they corrode due to the tropical marine climate affecting the building’s metal parts. The study uses different techniques, such as X-ray fluorescence spectroscopy (XRF), scanning electron microscopy/energy dispersive spectroscopy (SEM-EDS), X-ray diffraction (XRD), attenuated total internal reflectance Fourier transform infrared spectroscopy (ATR-FTIR), and cross-sectional microscopic analysis, to carefully look at the metal, corrosion products, and coating of the nameplate. The results show that (1) the nameplate matrix is a resulfurized steel with a high sulfur content (Fe up to 97.3% and S up to 1.98%), and the sulfur element is evenly distributed inside, which is one of the internal factors that induce corrosion. (2) Rust is composed of polycrystalline iron oxides such as goethite (α-FeOOH), hematite (α-Fe₂O₃), and magnetite (Fe₃O₄) and has typical characteristics of atmospheric oxidation. (3) The white and yellow-green coatings on the nameplate are oil-modified alkyd resin paints, and the color pigments are TiO₂, PbCrO₄, etc. The surface layer of the letters is protected by a polyvinyl alcohol layer. The paint application process leads to differences in the thickness of the paint in different regions, which directly affects the anti-rust performance. The study reveals the deterioration mechanism of resulfurized steel components in a subtropical polluted environment and puts forward repair suggestions that consider both material compatibility and reversibility, providing a reference for the protection practice of modern and contemporary architectural metal heritage in Macau and even in similar geographical environments. Full article

This study focuses on investigating the stability of modern and contemporary paints based on manganese violet pigment PV16 (NH₄MnP₂O₇) when exposed to atmospheric pollutants, specifically sulfur dioxide (SO₂) in the presence of high relative humidity. In particular, this study aims to investigate the role of PV16 in increasing the degradation processes of various modern binders. Therefore, the objectives of this research can be divided into (i) evaluating the chemical modifications involving PV16, (ii) investigating the degradation processes that occur in different organic matrices (i.e., drying oil, alkyd resin, and acrylic and styrene–acrylic emulsions), and (iii) comparing the chemical stability of model and commercial paints. The paints were analyzed by 3D Optical Microscopy, Attenuated total Reflection–Fourier-Transform Infrared spectroscopy (ATR-FTIR) and μ-Raman Spectroscopy, Scanning Electron Microscope coupled with Energy Dispersive X-Ray spectroscopy (SEM-EDX), X-Ray Powder Diffraction (XRPD), Fiber Optic Reflectance Spectroscopy (FORS), Pyrolysis–Gas Chromatography–Mass Spectrometry (Py-GC/MS), and Thermally assisted Hydrolysis and Methylation (THM) of Py-GC/MS (THM-Py-GC/MS). The results show that when exposed to high relative humidity and SO₂, PV16 presents a colorimetric change from violet to grey; several compounds crystallize on the surface; and, depending on the binder, various degradation reactions occur. This study highlights the susceptibility of manganese violet pigment PV16 under certain environmental conditions, which may be considered to define adequate conservation strategies for works of art containing this specific pigment. Additionally, the results obtained within this investigation point out the need to expand the chemical knowledge of this material for engineering, sensing, and industrial applications. Full article

Acrylic resins are widely favored for bamboo protective coatings due to their superior weather resistance; however, their widespread application is limited by their inherent drawbacks, including brittleness, inadequate adhesion, and poor water resistance. In this study, an innovative composite modification strategy, pre-blending alkyd resin with selected modifiers, was developed to enhance the adhesion, water resistance, and toughness of acrylic resin paint films. Compared to unmodified acrylic resin, the optimal group exhibited enhanced adhesion strengths of 4.21 MPa on tinplate and 7.36 MPa on bamboo, representing improvements of 31.56% and 29.35%, respectively. This was accompanied by a 205 g increase in scratch resistance and a 44% decrease in water absorption, indicating a concurrent enhancement in toughness, strength, and water resistance within the composite system. As revealed by X-ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR) analyses, this enhancement was attributed to the formation of a multidimensional network structure arising from synergistic interactions among the modifier, the alkyd resin, and the acrylic resin. This study provides a theoretical basis for developing high-performance coatings for bamboo protection. Full article

The growing concern over the transmission of pathogens, particularly in high-risk environments such as healthcare facilities and public spaces, necessitates the development of effective and sustainable antimicrobial solutions. Traditional coatings often rely on metals, which despite their efficacy, pose significant environmental and economic challenges. This study explores the potential of bio-based alkyd resins, supplemented with natural antimicrobial bioadditives, as an eco-friendly alternative to traditional antibacterial and antiviral coatings. Specifically, alkyd formulations incorporating thymol and soft resins extracted from hops were evaluated for antimicrobial and antiviral efficacy, following ISO standards (ISO 22196:2007 and ISO 21702:2019, respectively). The coating formulations showed significant activity against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus), and Influenza A (H3N2) virus, proving their potential for mitigating pathogen spread. These bio-based coatings not only reduce reliance on harmful chemicals but also align with circular economy principles by repurposing industrial by-products. This innovative approach represents a significant step toward greener antimicrobial technologies, with broad applications in healthcare, public infrastructure, and beyond, especially considering the rising zoonotic disease outbreaks. Full article

Alkyd resins are still one of the most important classes of binders for paint systems. They are outstanding in terms of their versatility of formulations and applications, cost-effectiveness, and durability. Traditionally, they are synthesized using phthalic anhydride, polyalcohols with three or four functional groups (pentaerythritol, glycerol, and trimethylolpropane), and fatty acids or oils. In this study, new bio-alkyd resins were synthesized with the objective of increasing the bio-based content by substituting phthalic anhydride, thereby also enhancing the biodegradability of coatings. The newly synthesized alkyd resins, formulated with azelaic acid, were used to develop coatings incorporating additives while avoiding cobalt-based driers. Additional agents such as leveling, wetting, and anti-skinning agents, were also included. Paints were applied to wood substrates and dried at room temperature. The resulting films were characterized by pendulum hardness, transparency, and color by colorimetry, cross-cut test, contact angle, and gloss. Thermal properties were analyzed by Differential Scanning Calorimetry (DSC), and Total Organic Carbon (TOC) content and aerobic biodegradation were also evaluated. The resulting coating films exhibited good mechanical performance, with hardness values ranging from 132 to 148 Persoz oscillations and strong adhesion to wood substrates (smooth cross-cut edges, Class 0). Significant biodegradability (70% in less than 90 days) was demonstrated under composting conditions, which was considerably higher than that of a commercial reference alkyd coating (34.7%) under the same conditions. These findings suggest that the developed bio-alkyd coatings formulated with azelaic acid and DCO-FA without cobalt-based driers represent a promising alternative to conventional phthalic acid-based alkyds. These novel coatings move closer to fully bio-based formulations and offer enhanced biodegradability, making them a more sustainable option for coating applications. Full article

Background: One of the foremost causes of microbial infections and propagation is improper sanitation and hygiene maintained in public places. Accumulation of stains and microbes results in the spread of infections. Also, due to the extensive use of non-renewable materials like petrochemicals, etc., there is an increasing demand for sustainable growth in the coating industries. Currently, there is no such technology that tackles this problem. Methods: Our present work aims to find a prolonged solution for these problems for the first time by synthesizing and formulating bio-based coatings with inherent antimicrobial properties and durable surface properties with a fast air-curing system. A formulation of alkyd and polyesteramide resins from castor, neem, and karanja oils was crosslinked with isocyanates to form the surface coatings. An esterification reaction of castor oil monoglyceride and phthalic anhydride synthesized the castor oil alkyd resin. The corresponding neem and karanja oil polyesteramides were synthesized by amidation with diethanolamine, followed by an esterification reaction. Results: The coatings exhibit an antimicrobial efficacy of 74%–84% against both Gram-positive and Gram-negative bacteria and contain 76.5% bio-based content. Factors such as thermal stability, physicochemical properties, and chemical and solvent stability were studied. After 24 h of inoculation with 40% polyesteramide resin (AMRESN-4), E. coli and S. aureus CFU values decreased from 6 × 10⁵ to 0.28 × 10⁵ CFU/g and from 5.7 × 10⁵ to 0.26 × 10⁵ CFU/g, respectively. These bio-based coatings are particularly suited for environments requiring high durability and antimicrobial protection, such as food-processing facilities, healthcare settings, and public restrooms. Full article

Iron corrosion is very common in our daily life, and its effective protection can extend its service life. As a small molecule monomer, 2-hydroxyethyl methacrylate phosphate (HEMAP) has a phosphate group that can effectively chelate with iron ions to form a passivation layer (iron phosphate), thus slowing down the corrosion rate of iron. This study synthesized HEMAP-modified acrylic–alkyd resin copolymers with variable concentrations using free radical polymerization. The addition of HEMAP not only increases the cross-linking density of the resin, but it also further strengthens the adhesion between the resins and the iron substrate, which prevents corrosive substances from penetrating the resin. According to electrochemical studies, adding 2% mass fraction of HEMAP to the resin could greatly increase its resistance to corrosion. This study reveals HEMAP’s capacity to enhance the protection of coatings on iron substrates and lengthen the metal’s service life. Full article

Hangzhou was the political and economic center of the Southern Song Dynasty (1127–1279 AD) and also the southern end of the Beijing-Hangzhou Grand Canal during the Ming and Qing Dynasties (1368–1644 AD). This historical position allowed the city’s economy to develop rapidly and influenced the form of its polychrome paintings with the imperial official style of the north China. However, due to the high temperature and rainy natural preservation conditions, southern polychrome paintings have always been a weak link in Chinese architectural polychrome painting craftsmanship. This study focuses on two well-preserved official-style architectural polychrome paintings in the grand halls from the late Qing period in Hangzhou. Through multi-techniques such as optical microscopy (OM), scanning electron microprobe with energy dispersive X-ray spectroscopy analysis (SEM-EDX), micro-Raman spectroscopy, micro-Fourier Transform Infrared spectroscopy (μ-FTIR), and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), it was found that there is a significant difference from the reported common non-ground architectural paintings in the south, typically having four-layer structures with a white base and ground plaster layer in preparation for painting. The appearance of pigments such as artificial ultramarine (Na₆Al₄Si₆S₄O₂₀) and emerald green (Cu(C₂H₃O₂)₂·3Cu(AsO₂)₂) indicates that the paintings were made at least after the 1830s, and the use of malachite green dye and copper phthalocyanine blue (PB 15:X) suggests that unrecorded restorations were also performed after the 20th century. All samples are coated with a layer of alkyd resin, which may have been added during the repairs in the latter half of the 20th century, leading to the black discoloration of the present paintings, especially in areas where emerald green was used. This study provides an important case for the study of the official style of polychrome painting craftsmanship in the southern region of China and also offers important references for the future protection and restoration of traditional architectural polychrome painting. Full article

Corrosion is the deterioration of metals due to environmental exposure. Commercial inhibitors used to control corrosion often contain heavy metal salts, which are highly toxic to both the environment and human health. A biosurfactant produced by the bacterium Pseudomonas cepacia CCT 6659 was tested as a corrosion inhibitor on carbon steel and galvanized iron surfaces. Matrices based on plant ingredients with different compositions were tested in a laboratory-constructed accelerated corrosion chamber (ACC) simulating a critical maritime atmosphere in conditions of 40 °C, 5% NaCl, and 100% humidity. The most stable matrix was selected for biosurfactant incorporation in different concentrations, expressed as critical micellar concentration (CMC), and was applied to metal surfaces to evaluate its ability to inhibit corrosion. Additionally, to evaluate the potential of the biosurfactant as a low-toxicity corrosion inhibitor additive in paint systems, iron and carbon steel samples were coated with three biosurfactant-containing commercial paints and subjected to critical atmospheric conditions for testing coating effectiveness. The formulation containing vegetable resin as a plasticizer, oleic acid, ethanol, and CaCO₃ was chosen to incorporate the biosurfactant. The addition of the biosurfactant at twice its CMC led to a reduction in carbon steel sample mass loss from 123.6 to 82.2 g/m², while in the galvanized iron plates, the mass loss decreased from 285.9 to 226.7 g/m² at the same biosurfactant concentration. When supplemented with the biosurfactant, the alkyd resin-based paint (A) ensured less mass loss in samples (46.0 g/m²) compared to the control without biosurfactant (58.0 g/m²). Using the paint formulated with oil-based resin (B), the mass loss decreased from 53.0 to 24.1 g/m², while with that based on petroleum derivatives (C), it decreased from 82.2 to 27.6 g/m². These results confirm the feasibility of using biosurfactants in biodegradable coatings, reducing the need for commercial corrosion inhibitors. Full article