Journal of Coatings Technology and Research最新文献

This study employed an emulsification adsorption method to modify the surface of hollow glass microspheres (HGMs) with zinc oxide (ZnO) nanoparticles and investigated the impact of ZnO nanoparticles on the thermal insulation properties of the final synthesized composite coating. By regulating the amount of Zn²⁺ added, key performance indicators such as the thermal conductivity, temperature difference, adhesion, and solar reflectance of the ZnO-modified HGM-based thermal insulation coating were systematically analyzed. The experimental results indicate that the thermal insulation performance of the final coating significantly improves with an increase in Zn²⁺ content. Notably, when the Zn²⁺ concentration reaches 12.5 mmol, the temperature difference across the thermal insulation coating can reach up to 27.5 °C, an enhancement of 11.3 °C compared to the unmodified HGM-based coating. Additionally, the solar reflectance of the ZnO-modified thermal insulation coating increased significantly to 0.86, demonstrating superior thermal insulation effects. The study suggests that precise control of Zn²⁺ addition can significantly enhance the thermal insulation performance of HGM coatings, providing essential theoretical and practical insights for the design and application of high-efficiency thermal insulation materials.

Coatings with low surface energy can be promising in various fields of science and technology. It is well known that to achieve low surface energy, it is usually enough to form thin layer or even monolayer of hydrophobic compound on the surface of the coating. On the other hand, to increase stability, such monolayers should be covalently bonded with the surface. In this work, we have shown the possibility of the use of Piers–Rubinsztajn reaction for grafting of oligoorganosiloxane hydrophobic monolayer on the surface of phenol-formaldehyde, alkyd, and epoxy coating, most used in the paint and varnish industry. The organosilicon monolayers were studied by XPS, ellipsometry, and contact angle measurements. Additionally, coatings with grafted organosilicon monolayers were studied for the static effects of water. It was shown that the formed organosilicon monolayers exhibit good hydrophobic efficiency, with an increase in contact angle from 75° to 116° for phenol-formaldehyde coatings, from 82° to 107° for alkyd coatings, and from 84° to 100° for epoxy coatings.

Endoscopes are essential for visualizing the human body’s interior in modern medicine. However, they face issues due to bodily fluid buildup during surgery, which hinders their function. A potential solution is applying a hydrophobic layer, such as polytetrafluoroethylene (PTFE), to the lens. This prevents fluid adhesion, simplifies cleaning, and enhances visibility. This study investigated dip and spin coating techniques to develop hydrophobic surfaces using PTFE on three lens materials: acrylonitrile butadiene styrene (ABS), styrene acrylonitrile (SAN), and polycarbonate (PC). Physicochemical attributes of uncoated and PTFE-coated samples were evaluated. Both dip and spin coating techniques achieved successful PTFE coating on ABS-, SAN-, and PC-based endoscope lenses. Dip-coated PTFE SAN samples exhibited higher light transmittance, while spin-coated SAN samples showed greater water contact angles. Scanning electron microscope and atomic force microscope analyses revealed uneven distribution and roughness with dip coating, while spin coating uniformly deposited a hydrophobic PTFE layer on the SAN-based endoscope lens. TGA and DSC findings revealed minimal impact of PTFE coatings on the thermal stability of SAN. Compared with commercially coated SiO₂ and TiO₂ samples, the PTFE-coated samples showed superior hydrophobic properties and comparable light transmittance. This study highlights the capability of PTFE coating to improve the water-repelling properties of endoscope lenses while preserving their ability to transmit light effectively.

The degradation and erosion of wood and its products caused by microorganisms remains a persistent challenge, which leads to significant economic and property losses and poses a potential health threat to users due to the presence of pathogenic microorganisms. In light of the recent COVID-19 pandemic, this issue has become increasingly urgent to address in modern society due to the increasing focus on private health. In this work, the carboxymethyl chitosan nano-silver (CMCS-Ag) was prepared through a microwave-assisted method, where the CMCS-Ag was ultrasonically blended with waterborne paint to obtain a waterborne antimicrobial wood coatings. Compared with commercial nano-silver with the same particle size, due to the unique system, the CMCS-Ag exhibited superior antibacterial efficacy and lower Ag⁺ release. CMCS-Ag exhibited effective dispersion within waterborne coatings, leading to a significant improvement in both the mechanical and antimicrobial performance of the coatings. With a CMCS-Ag content of 10 wt%, the coating films exhibit high elastic modulus, tensile strength and shore hardness, 78%, 33% and 69% higher than the control, respectively. Moreover, antimicrobial tests confirm that CMCS-Ag wood coatings inhibit Escherichia coli (24 h sterilization rate: 99.99%), Aspergillus niger (28 days without erosion), and soil decay fungi (56 days undecayed), while minimizing wood product appearance deterioration and mass loss from microbial erosion. These findings not only provide valuable insights into enhancing the antimicrobial of wood and its products but also reduce possibilities for people exposed to pathogens.

The Hansen solubility parameters (HSPs) describe the solubility behavior of substances, allowing the prediction of a substance’s solubility in combination with solvents with known HSP values. This work introduces a “solvent finder,” a user-friendly Python program designed to calculate suitable solvents for substances based on their HSPs. The application facilitates and accelerates the solvent selection process for specific substances and is freely accessible. The program is based on HSPs, which indicate the compatibility of two compounds based on their solubility parameters. Its primary goal is to automate the selection process by systematically calculating all possible solvent combinations based on the given HSP values. Users can input and configure the HSP values for any number of solvents within the parameter setup. Additionally, the program provides the flexibility to consider up to five substances simultaneously when dealing with polymer mixtures or the general compatibility of mixtures. The applicability of the HSP is not restricted to specific substance classes, such as polymers or solvents, allowing the tool to be used for a wide range of formulations and coatings.

Coatings are widely applied to protect wood from hygroscopicity, flammability, biological degradation, and surface weathering. Weathering, a surface phenomenon, significantly impacts the appearance, service life, and performance of wood coatings. Over time, external factors degrade coating performance. This study examines how Ferula asafoetida essential oil improves polyurethane (PU) coatings. GC-MS analysis identified 26 major compounds in the oil, with (E)− 1-propenyl sec-butyl disulfide (39.14%) as the most abundant. The essential oil was mixed with water-based PU (0.5%) and applied to beech and pine wood surfaces. Coating performance was evaluated through fungal resistance, mold growth, discoloration, and adhesion tests, both before and after weathering. Results showed that the essential oil-enhanced PU coating (PU + E) exhibited significantly improved fungal and mold resistance compared to PU and control samples. Although the functionality of PU + E coatings diminished over time, they remained superior to untreated samples after aging. Weathering induced substantial color changes in both coated and uncoated samples. Adhesion tests revealed that the PU + E coating adhered better to beech than pine wood. Essential oil did not affect coating strength initially, but PU + E coatings performed better than PU after weathering.

The post-harvest loss of fruits and vegetables poses a significant challenge in the agricultural sector, especially in regions with suboptimal storage and transportation conditions. These losses not only lead to economic setbacks but also contribute to food insecurity worldwide. In recent years, nano-films have emerged as an innovative solution to address these issues by extending the shelf life and maintaining the freshness of harvested produce. Nano-films typically composed of biocompatible biopolymers like chitosan, cellulose, and alginate often incorporate nanoparticles such as silver, zinc oxide, and titanium dioxide for their antimicrobial properties. These films form a protective, semipermeable barrier that regulates moisture and gas exchange, slows respiration rates, and reduces microbial growth on produce surfaces. This review discusses the composition and mechanisms of action of nano-films, including moisture control, antimicrobial protection, and UV-blocking effects, and evaluates their applications across various types of produce, from fruits and leafy greens to root vegetables. By examining the benefits, challenges and future directions of nano-film technology, this review highlights the potential of nano-films as a sustainable, cost-effective tool for reducing post-harvest losses and promoting food security.

The synthesis of dimethylaminopropylmethacrylamide-benzylammonium chloride (QD-BC), a kind of acrylamide quaternary ammonium salt, through the combination of N-dimethylamine propyl methacrylamide and benzyl chloride (BC) is presented in this paper. The structure of QD-BC was analyzed using FTIR, carbon spectrum, mass spectrometry and ¹HNMR spectroscopy. The resulting product was then utilized for the preparation of light-cured antimicrobial coatings. The mechanical properties of the light-cured coatings were evaluated through drawing tests, etc. The antimicrobial efficacy of coatings with varying contents of QD-BC against E. coli and S. aureus was investigated. The results indicate that the coating with the QD-BC content of 7.2% exhibits maximum adhesion strength, reaching 0.87 MPa. Moreover, when the QD-BC content is 6%, the coating displays a hardness value of 5H while maintaining good flexibility throughout all formulations tested. The coating with QD-BC content of 7.5% shows the highest impact strength among all compositions studied. Furthermore, at respective concentrations of 7.5% and 4.2% for the E. coli and S. aureus testing strains, these coatings demonstrate complete antimicrobial activity with exceptional durability.

Strip steel products are painted via a sequential, multistep application of various paint layers. This imparts properties, such as adhesion, corrosion protection and aesthetics, to the final finished product. However, various techniques, including slide coating, allow for simultaneous deposition of multiple paint layers. Here, we examine whether a similar system could be used for steel coil coating, without the requirement for expensive production-scale testing. Hansen solubility parameters (HSPs) were used to test the applicability of a typical, three-layer coil coating paint system for gradient self-stratification in wet-on-wet paint application techniques. As expected, the paint components are found to layer when placed on top of each other, remaining that way for some time. HSP analysis suggests, however, that the interlayer compatibility of some of the layers could be improved by solvent addition or substitution to produce a more graduated self-stratifying coating suitable for use in wet-on-wet techniques. Adhesion testing has subsequently indicated that cohesive failure occurs within the midcoat layer of the paint system, but adhesive failures are possible between the midcoat and topcoat layers. Using HSP-tailored paint systems in wet-on-wet paint application techniques, it may be possible to improve coating layer adhesion by “designing-in” gradient stratification during paint deposition.

This study presents the development of an advanced intumescent fire-retardant coating by integrating lanthanum hypophosphite (LaHP) into a conventional ammonium polyphosphate/pentaerythritol/melamine (APP/PER/MEL) system. LaHP was synthesized from sodium hypophosphite and lanthanum chloride, achieving a yield of approximately 65%. The synthesized LaHP was added to the coating formulation at concentrations ranging from 2 to 6 wt.% to evaluate its effects on fire resistance and thermal protection. Comprehensive testing, including fire resistance assessments and cone calorimeter tests, along with characterizations such as SEM, XRD, Raman spectroscopy, FTIR, TGA, and XPS, revealed that LaHP significantly enhanced the fire-retardant properties of the coatings. The optimal concentration of 4 wt.% resulted in a peak heat release rate (pHRR) of 37.04 kW/m² and a total heat release (THR) of 0.42 MJ/m². Additionally, the LaHP-enhanced coating demonstrated superior thermal barrier efficiency, keeping the backside temperature of the coated steel plate below 200 °C during fire testing. Morphological analyses indicated that LaHP contributed to a denser, continuous char layer that insulated against heat and oxygen. XPS analysis confirmed the formation of a catalytic graphitized carbonaceous layer, which delayed degradation of the intumescent structure and improved fire retardancy. Briefly, LaHP proves to be an effective synergist in the APP/PER/MEL system, which markedly enhances the coating of fire protection performance.