Journal of Coatings Technology and Research最新文献

Oriented strand board (OSB) is widely used due to its unique texture and bonding strength, making the study of transparent fireproof coatings that preserve its aesthetic qualities both theoretically and practically significant. The transparent properties of vinyl acetate-ethylene copolymer emulsion (VAE emulsion) after curing, combined with traditional intumescent flame retardants, enable effective flame retardation of OSB boards. Inspired by this, different metal synergistic components (diethyl aluminum hypophosphite and magnesium hydroxide; aluminum sulfate and magnesium sulfate) compounding intumescent flame retardants (IFR: ammonium polyphosphate, melamine and pentaerythritol) were incorporated to enhance the flame retardancy and smoke suppression of VAE emulsion coating. The results show that, compared to fire retardant coatings with only the addition of IFR, the incorporation of Si-Mg-Al (Na₂O·nSiO₂/MgSO₄/Al₂(SO₄)₃) synergists resulted in an approximately 7.3% reduction in peak heat release rate and an approximately 31% reduction in peak smoke release rate. Additionally, the total smoke production per unit area also significantly decreased. This work presents a novel approach for producing intumescent fire retardant coatings with enhanced fire resistance and smoke suppression properties.

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The development of a solvent-free, ambient and efficient approach to fabricating anti-corrosion coating has long been a desirable goal. In this work, a novel kind of electron beam cured coating with outstanding anticorrosion property was prepared. Polyaniline-micaceous iron oxide (PANI-MIO) was used as anticorrosion filler, which was prepared by the in-situ polymerization method on the surface of micaceous iron oxide (MIO). It only took several seconds to achieve the complete curing at room temperature and no organic solvent was involved. The curing behavior of PANI-MIO coatings was explored through gel content and double bond conversion rate tests. Combining the active anticorrosive mechanism of PANI and the passive shielding anticorrosive mechanism of MIO, the EB-cured PANI-MIO coatings were endowed with “active + passive” anticorrosion functions and the anticorrosion performance was significantly improved. The effect of the ANI/MIO ratio as well as the PANI-MIO content on the coating property and anticorrosion performance was systematically investigated. At the optimum conditions, the EB-cured composite coating exhibited outstanding anticorrosive performance. The low-frequency impedance value of the coating was still above 10⁹ Ω cm² after 45 days’ immersion in NaCl solution, which was about two orders of magnitude higher than that of the pure resin coating. In addition, the corrosion protection efficiency was nearly 96%, which was approximately twice that of MIO coatings. Furthermore, for damaged coatings, no obvious corrosion spread was observed at the scratch after 600 h of neutral salt spray testing. This work provided a benchmark for the EB curing of coatings for metal corrosion protection.

Solar-driven interfacial evaporation offers a promising solution to global water scarcity. Recent advancements have improved its efficiency by focusing solar energy on hydrophobic photothermal materials. However, energy loss due to the air layer between the hydrophobic materials and water surface remains a key challenge, limiting both water evaporation and solar energy utilization. In response to this challenge, a novel Janus membrane with asymmetric wettability has been developed using simple electrochemical oxidation and spraying techniques. The asymmetric Janus membrane, with hydrophilic polypyrrole and hydrophobic polydimethylsiloxane layers, enhances interfacial heating and solar-driven water evaporation. Wettability tests show contact angles of 21° and 128° for the hydrophilic and hydrophobic surfaces, respectively. The Janus membrane achieves 96.53% light absorption in the visible spectrum and a water evaporation rate of 2.37 kg m⁻² h⁻¹ under simulated sunlight, with a maximum water temperature of 47 °C. These findings present the Janus membrane as a promising material for applications in solar-driven desalination and water purification, contributing to advancements in sustainable water management technologies.

Hydrolysable tannins are natural polyphenols susceptible to hydrolysis that can be extracted from different vegetable plants. Tara pods, of Peruvian origin, concentrate a high tannin content and, besides their low exploitation impact, their tannin extract has shown high potential industrial applications due to their ability to form complexes with a broad variety of metal ions. However, developing an anticorrosive pigment of low-cost, high efficiency and reduced environmental impact is still a challenge. Herein, tannin-rich pigments were synthesized with Tara powder and zinc ions to produce metallic complexes known as tannates for corrosion protection. The anticorrosive behavior of zinc tannates was studied by direct current electrochemical techniques on pigment extracts and electrochemical impedance spectroscopy tests by analyzing pigmented primers and painting systems. Scanning electron microscopy and energy dispersive analysis were performed to study the protective layers morphology. Results indicated that zinc tannates inhibit satisfactorily steel corrosion overcoming the recognized behaviour of conventional pigments. As part of a painting system, alkyd primers with zinc tannates presented the best inhibitory properties. Zinc tannates could have the necessary requirements to be considered anticorrosive pigments, becoming a green alternative for corrosion prevention.

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The high corrosion susceptibility of biomedical magnesium alloy has become a practical problem which restricts its orthopedic application. To enhance its surface properties, PHPS-derived coatings were fabricated on the surface of AZ31B magnesium alloy using a simple polymeric precursor method. The resulting thin coating, about 2 μm thick, possessed a dense surface structure and had an adhesion strength of 4B. The effect of different curing temperatures on the coating composition, corrosion resistance and biocompatibility was systematically investigated. The coating cured at 200–300 °C showed the best corrosion resistance in a phosphate-buffered saline solution, providing good protection for magnesium alloy with a degradation rate about 10% of that of bare alloy. Cytotoxicity tests indicated that the coatings enabled higher cell viability compared to uncoated samples. These findings advance the understanding of the service performance of PHPS-derived coating in corrosive environments and support the broader application of magnesium alloys in biomedical fields.

This study develops and explores a self-stratifying coating system that incorporates both epoxy and acrylic resins. It examines the impact of film thickness and substrate type on self-stratification behavior, confirms predictions from the surface energy model, and identifies the surface tension gradient as the primary driving mechanism for stratification. Additionally, this research investigates the influence of FeSiCr powder on the stratification behavior of the coating. Results demonstrate that the self-stratifying coating, composed of a blend of epoxy and acrylic resins with FeSiCr powder, exhibits superior corrosion resistance compared to coatings formulated solely from a mixture of epoxy resin and FeSiCr powder. SEM-EDS analysis reveals that the enhanced corrosion resistance can be attributed to the accumulation of epoxy resin and FeSiCr at the bottom of the coating, while the acrylic resin forms an effective protective layer on the surface. Furthermore, the study examines the effects of FeSiCr powder content, solvent addition, and volatilization rate on the stratified structure and appearance of the coating. The findings indicate that at relatively low FeSiCr powder content, the layered structure of the coating remains largely intact, with the powder predominantly residing within the epoxy resin layer. However, increasing the powder content compromises the self-stratification structure, leading to a rougher coating surface. It is also observed that augmenting the quantity of the xylene/butyl acetate mixture reduces pit formation on the surface, while the use of MIBK solvent results in incomplete stratification and exacerbates surface roughness.

MXenes, known for their unique properties and versatility, have garnered massive applications in fields such as energy storage, water purification, and fire-retardancy. However, while highly effective, MXenes raise significant concerns regarding toxicity, environmental impact, and synthesis methods, which often involve hazardous chemicals. In response, incorporating bio-based additives (derived from plant or animal sources) emerges as a promising strategy to enhance MXene effectiveness, mitigate toxicity, and promote sustainable practices. This review explores the synergistic potential of combining MXene with bio-derived materials, including plant-based additives like lignin, cellulose, and soy protein, and animal-based counterparts such as DNA, casein, and chitosan. These combinations have demonstrated significant improvements in flame retardancy, with peak heat release rate (PHRR) reductions of up to 83%, total heat release (THR) reductions of 69%, and total smoke release (TSR) reductions exceeding 85%. Additionally, MXene-bio composites have achieved limiting oxygen index (LOI) values surpassing 45%, highlighting their enhanced thermal stability and self-extinguishing properties. Beyond their fire-retardant benefits, these materials also contribute to a reduced environmental footprint by replacing synthetic additives with biodegradable and renewable components. Additionally, the review addresses critical challenges, such as developing scalable, eco-friendly synthesis methods and navigating regulatory requirements, aiming to provide a comprehensive perspective on advancing MXene-bio composites toward sustainable fire-retardant applications.

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This study aimed to evaluate the post-harvest quality of table grapes (Vitis vinifera) with edible coating with green banana starch (2.5 and 5.0%) and plasticizers (mannitol and glycerol). The green banana starch films were characterized by X-ray diffraction and Fourier transform infrared spectroscopy. The grapes were stored at 18°C for 21 days and subjected every 7 days to determinations of mass loss, soluble solids (SS), pH, titratable acidity (TA), and color (L*, a* and b*). For the film characterization, the mannitol provided higher crystallinity compared to the glycerol. This crystallization is promising since it reinforces the polymer network, influencing the mechanical properties of the films. For the physicochemical analysis of the grapes, the coatings containing mannitol were more effective in maintaining the quality of the grapes and providing lower (p < 0.05) values for weight loss, SS, and TA up to 14 days. Thus, using 2.5% starch with mannitol or 5.0% starch with mannitol is promising for grapes’ quality and shelf-life.

A series of environmentally friendly and odorless CO₂-based waterborne polyurethanes (PPCD-WPUs) were synthesized by changing the traditional acetone process without adding organic solvents (acetone) and volatile ammonia (triethylamine) in the whole preparation process. Firstly, through formula design, we changed the size of the R value and used inorganic base (NaOH) as a neutralizing agent, and then increased the temperature of H₂O to avoid the high viscosity problem caused by traditional emulsification processes. When the R value of the prepolymer is 1.88 and the temperature of H₂O is 40°C, environmentally friendly solvent-free waterborne polyurethane can be prepared. The particle sizes of the PPCD-WPUs prepared by this method are between 45 and 70 nm, the appearance is transparent and the emulsion shows good stability. By using EDA to extend the chain, the mechanical strength of PPCD-WPU can be effectively improved. When the R value is 1.88, the tensile strength of the film is 30.8 mPa and the elongation at break is 547.8%. However, when H₂O is used as chain extender, a large number of terminal amino groups appear, the absorption peak of chromogenic groups is obvious, and the performance decreases. With the increase in R value, the water absorption decreases from 13.5 to 7.9 wt%, and the thermal decomposition temperature decreases slightly (5 wt% loss temperature from 253.6 to 228.5°C). Moreover, the prepared PPCD-WPU has high UV transmittance. This study has a positive guiding significance for the green industrial production and application of CO₂ copolymer-based polyurethane in the future.

Chitosan (CS), a naturally derived polysaccharide, exhibits inherent biocompatibility and moderate antimicrobial activity; however, its efficacy against resistant and biofilm-forming pathogens remains limited. To enhance its bioactivity, CS was chemically modified through N-phthaloylation and O-/N-acylation with L-arginine, yielding derivatives including N-phthaloyl chitosan (Ph-CS), N-acylated chitosan (N-Arg-CS), O-acylated chitosan (O-Arg-CS), and O-N-acylated chitosan (O-N-Arg-CS). Characterization using FTIR, SEM, TEM, EDX, and TGA confirmed successful structural and morphological modifications. O-N-Arg-CS exhibited significant improvements in thermal stability, porosity, and nanoscale morphology, with particle sizes ranging from 100 to 150 nm. Antimicrobial assays demonstrated that O-N-Arg-CS had the highest efficacy, with inhibition zones of 27 mm against Pseudomonas aeruginosa, 25 mm against Klebsiella pneumoniae, and 21 mm against Staphylococcus aureus. It also exhibited over 100% biofilm inhibition at 300 mg/mL for all tested pathogens. Cytoplasmic protein leakage studies indicated strong membrane-disruptive effects, with the highest leakage observed for P. aeruginosa (312 µg/mL). N-Arg-CS and O-N-Arg-CS also showed dose-dependent killing efficiency, completely eradicating microbial populations within 60–90 min at concentrations as low as 150 mg/mL. These findings highlight the potential of O-N-Arg-CS as a highly effective and biocompatible antimicrobial agent. Its strong broad-spectrum activity, biofilm inhibition, and low toxicity make it a promising candidate for coatings on medical implants to combat biofilm-associated and multidrug-resistant infections. These results establish O-N-Arg-CS as a highly effective and safe antibacterial biomaterial, demonstrating significant translational potential for medical implant coatings.