Journal of Coatings Technology and Research最新文献

The hydrophilic nature of Algerian palygorskite (A-Pal) limits its effectiveness as a nanofiller in biopolymeric matrices due to the aggregation of its nanostructures. This study addresses this limitation by modifying the surface of (A-Pal) with triethoxyoctylsilane (TEOS) to impart hydrophobicity and enhance its compatibility with hydrophobic biopolymers. The effectiveness of this surface modification, as well as its impact on the morphology, crystal structure, surface properties, and thermal behavior of the modified palygorskite (O-Pal), was evaluated through a comparative analysis of pristine and modified samples. Fourier transform infrared spectroscopy (FTIR) and X-ray fluorescence (XRF) confirmed the successful grafting of silane onto the clay mineral surface. Additionally, X-ray diffraction (XRD) and scanning electron microscopy (SEM) demonstrated that the crystal structure of palygorskite was functionalized yet preserved following modification. Thermogravimetric analysis (TGA) indicated an enhancement in thermal stability, estimated at 14 °C, along with a 14.6% reduction in total weight loss. While BET surface analysis showed enhanced surface properties with an increase in S_BET from 121 m²/g for A-Pal to 152 m²/g for O-Pal. These findings suggest that triethoxyoctylsilane-modified palygorskite is a promising nanofiller for the development of bio-nanocomposites with improved thermal and hydrophobic properties.

Developing new recipes for waterborne polymer latex binders with improved colloidal stability and application performance is crucial for sustainable, eco-friendly textile printing processes. For this purpose, 15 waterborne poly(vinyl acetate-co-butyl acrylate) latexes were synthesized by semi-continuous emulsion polymerization using nonionic (ABIL^® B 8843, ABIL^® B 88184) and amphoteric (ABIL^® B 9950) silicone-based surfactants at five concentrations close to their critical micelle concentrations (between 0.08 and 0.24 wt.%). Other critical synthesis conditions, such as the fixed monomer ratio (85:15), initiator amount, stirring rate, total reaction time, and temperature, were kept constant to ensure reproducibility and reaction consistency in all formulations. A comprehensive characterization of the synthesized latexes was performed, colloidal stability was monitored over one year, and latexes that did not exhibit phase separation were utilized in textile pigment printing applications on both woven and knitted cotton fabrics. The AB-50-020 sample prepared using ABIL^® B 9950 at 0.20 wt.% exhibited the highest colloidal stability, characterized by a zeta potential of − 75.67 mV and the smallest particle size of 323.6 nm. Despite the high relative conversion rates (94.3–99%) of the samples obtained from ABIL^® B 8843 and ABIL^® 88184, the number of samples showing long-term stability among the formulations in these series was low, limiting their practical applications. The rubbing, washing, and color fastness, especially in formulations containing ABIL^® B 9950, highlight their suitability as sustainable alternatives for textile applications on woven and knitted cotton fabrics.

This study presents a straightforward electrodeposition strategy for fabricating a polytetrafluoroethylene (PTFE) coating with excellent stability on stainless steel substrates, aimed at inhibiting the deposition of MgO/CaCO₂ mixed fouling. By tuning the electrodeposition parameters, two hydrophobic coatings were achieved with surface roughness values of 0.148 μm (No.1 coating) and 0.056 μm (No.2 coating). The static and dynamic antifouling performance of these coatings was systematically evaluated at different temperatures (50 °C and 90 °C). The results indicate that both the surface morphology of the coatings and the temperature jointly affect the fouling suppression efficacy. No.1 coating preferentially adsorbed fouling particles due to its microprotrusion structure. Conversely, under dynamic flow conditions at 90 °C, No.2 coating exhibited a smooth surface and a significant bubble retention effect, resulting in a higher fouling inhibition rate of 82.83%. Overall, this research provides a strong foundation for future studies and practical applications of PTFE coatings in antifouling technologies.

This study assessed the safety of readily available film-forming (nitrocellulose lacquer, polyurethane, and water-based polyurethane) and penetrating finishes (linseed oil, mineral oil, and beeswax) applied to Samanea saman (Jacq.) Merr. (rain tree) wood. Residues from evaporation, potassium permanganate consumption, and UV-Vis analysis were evaluated with regards to food safety. The durability of the applied film-forming finishes was also tested following standard methods. All the film-forming finishes complied with EU migration limits under the residue on evaporation test, while none of the penetrating finishes passed. Unfinished rain tree samples displayed significantly high overall migration. Furthermore, all finishes, except PU, exhibited high levels of oxidizable components. Except for PUw and BW, all finishing materials passed the UV-Vis test. No lead, mercury, cadmium, and arsenic heavy metals were detected in the migrants from different finishes. Polyurethane consistently demonstrated superior adhesion and film hardness, thus emerging as the most promising finish for wooden tableware and kitchenware. However, to ensure food safety, further investigation to identify the migrating compounds and assess their toxicity, especially from PU, is recommended.

Photocatalytic textile based on TiO₂ has great potential in organic pollutant degradation. The key to its preparation lies in the binding of TiO₂ nanoparticles (NPs) to textile via crosslinking agent. However, in order to reach adequate coating fastness, the commonly used crosslinking agents generally suffer too much usage, which greatly reduces the photocatalytic efficiency of TiO₂. To address this problem, a novel crosslinker containing a p-phenylenediamine center and four long silanol groups is developed in this work. It not only firmly binds TiO₂ NPs to textiles with small amount, but also improves photocatalytic performance of the composites that benefit from its redox-reversible feature. Photocatalytic textiles with different weight ratios of crosslinker to TiO₂ are prepared by the spray coating method. The sample with the ratio of 1:4 shows the best photocatalytic performance and simultaneously preserves good coating fastness. The degradation efficiency for methylene blue remains over 90% after four cycles of consecutive experiments. Compared with the composites prepared using other crosslinking agents, the textile in this work shows both higher photocatalytic performance and better binding strength.

Graphical abstract

Waterborne aluminum flake composite pigments (Al@KH550@SiO₂@SA) were prepared by successively encapsulating aluminum flakes with hydrolyzed γ-aminopropyl triethoxysilane (KH550) inside nanolayer, SiO₂ intermediate inorganic nanolayer, and stearic acid (SA) outside organic layer. Hydrolyzed KH550 nanoparticles anchored at the surfaces of Al flakes via Si–O–Al bonding, SiO₂ nanoparticles anchored at the hydrolyzed KH550 nanolayers via Si–O–Si bonding, and stearic acid molecules anchored at the SiO₂ intermediate nanolayers via the interaction between carboxylic groups and surface –OH groups. The encapsulation of SiO₂ intermediate nanolayer using environmentally friendly silica sol precursor obviously improved the anticorrosion performance of resultant composite pigments. The encapsulation of stearic acid outside organic layer endowed the composite pigments with good water floating performance. The lightness, brightness, and whiteness of encapsulated aluminum flake composite pigments are comparable to those of solventborne aluminum flake pigment.

Herein, we report the facile in-situ approach for the coating of polyaniline on different microfibers (polyester, cotton and wool) via the chemical oxidative polymerization method for supercapacitor application. Physicochemical characterizations (via FTIR, XRD and FESEM) were performed to confirm structure bonding properties, microstructure, and morphology which revealed the successful formation of polyaniline and its coating over microfiber surface. This could be attributed to electrostatic interaction (π–π interaction and H-bonding) between aniline monomer and surface functionality present over the fiber surface. Electrochemical analyses including cyclic voltammetry, charging-discharging, and impedance spectroscopy in conventional three-electrode configuration in aq 1 M KCl as an electrolyte further revealed improved electrochemical performance as compared to pure polyaniline. It was observed that polyaniline-coated wool fiber (PANI-WFs) exhibited maximum specific capacitance (62 F/g at current density 1A/g) as compared to pure polyaniline and others calculated by charging discharging analysis within the potential window − 0.2 to 0.8 V. This observation was in good agreement with respect to highest I–V characteristic profile measured by Keithley source meter revealed lower electrical resistance of PANI-WFs composite. This was further confirmed by the Nyquist plot and Bode plot which clarifies lower charge transfer resistance and higher charge storage capability than others.

This study explored the development of polyurethane (PU) films infused with citrus peel extracts derived from orange, lemon, and tangerine. The films were synthesized using polycaprolactone triol (PCL-T) and hexamethylene diisocyanate (HDI) and evaluated for their physicochemical, mechanical, thermal, and antibacterial properties. The results revealed that the incorporation of citrus extracts led to a reduction in the elastic modulus and strain at break compared to those of standard PU films. Thermogravimetric analysis revealed that the films were thermally stable up to 250 °C, while scanning electron microscopy (SEM) highlighted rough surfaces and cracks in the citrus-infused films. Antibacterial tests demonstrated that the films exhibited bactericidal activity against Escherichia coli. Additionally, the films provided significant UV-blocking effects, as evidenced by their ability to reduce the photodegradation of 2% resveratrol after 2 h, 8% after 4 h, and 21% after 8 h of UVA exposure. These findings suggest that citrus-infused PU films hold potential for use in applications such as wound dressings and packaging materials, providing both antibacterial protection and UV shielding.

Graphical Abstract

The surface performance and weathering resistance of wood products often depend on the applied coating and reinforcing additives. In this paper, polyester film with the contribution of ceramic nanoparticles (contains zinc oxide, ZnO) was deposited on the oak wood (Quercus castaneifolia) surfaces via atmospheric pressure plasma jet (APPJ) technology. The polyester coating applied with an applicator and uncoated wood samples served as controls. The surface properties such as surface roughness, contact angle, wear index, wear depth and hardness values of the samples were analyzed before and after 720-h exposure to the artificial accelerated weathering test. The results demonstrated that the surface properties of oak samples were considerably improved after coating, and superior performances were observed in the plasma-deposited coating layer, particularly the ones reinforced with ceramic nanoparticles. This indicates a potential for using the plasma deposition method for coating and enhancing the surface properties of wood.

The development of sustainable and environmentally friendly coatings is a key factor to shaping the future of coatings technology. Water-based products represent an eco-friendly alternative to conventional solventborne coatings, minimizing the environmental impact and allowing for easier application indoors. Until now, cellulose nitrate binders have not been used in waterborne formulations, due to challenging production of respective dispersions. Herein, we introduce an approach for such waterborne cellulose nitrate coatings, derived from respective nanoparticle dispersions. This enables a significant reduction in the content of volatile organic compounds. After nanoparticle synthesis via precipitation, the particles are used for formulation of a waterborne coating, which is stable at higher concentrations as well. Additionally, initial efforts to optimize the formulation for use on wooden surfaces by adjusting the NC content and incorporating diisononyl phthalate were investigated. These modifications resulted in considerable improvements over the standard formulation. As an additional benefit, we demonstrate the capability of the coating to act as a thermally triggerable primer regarding debonding on demand of a topcoat system.