Journal of Coatings Technology and Research最新文献

Na⁺–La³⁺ co-doped γ-Ce₂S₃ (abbreviated as γ-Na_0.5Ce_{2.5 − x}La_xS₄) pigments with a fixed Na/(Ce_1 − xLa_x) molar ratio of 0.2 (x = 0, 0.1, 0.5, 0.9, 1.3, 1.7, 2.1 and 2.5) were synthesized by low-temperature self-propagating combustion method. By adjusting the La³⁺ doping ratio, a series of γ-Na_0.5Ce_{2.5 − x}La_xS₄ pigments with different colors were obtained by sulfurizing at 900°C for 2 h using CS₂ as the sulfur source. The effects of La³⁺ doping amount on the synthesis of γ-Ce₂S₃, crystal structure, color performance, and temperature stability were systematically studied. The results show that the pigments exhibited a single cubic γ-Ce₂S₃ phase throughout the range of x increasing from 0 to 2.5. Compared with the co-precipitation method, the particle size of the pigment obtained by the low-temperature self-propagating combustion method decreased from 620 to 310 nm. Furthermore, as La³⁺ content increased, the band gap of the sample gradually increased from 2.06 to 2.90 eV, causing the color to change from red (L* = 39.42, a* = 40.35, b* = 30.28) to orange-red (L* = 49.15, a* = 35.51, b* = 40.64), then to orange-yellow (L* = 54.85, a* = 28.53, b* = 37.30), and finally to white-blue (L* = 66.66, a* = − 1.42, b* = 11.25). In addition, the thermal stability of γ-Na_0.5Ce_{2.5 − x}La_xS₄ was evaluated by TG-DSC and its thermal stability increased from 350 to 480°C.

Ice on the surface of wind turbine blades may result in power production losses and unsafe operations. An effective technological solution to the ice issue is coating de-icing. This study first constructed SiO₂ aerogel/CNTs (carbon nanotube) coating with photothermal de-icing by incorporating photothermal nanoparticles into the created nanoporous structure. The coating structure examined by SEM and EDS analysis demonstrates that CNT particles can be well captured by the three-dimensional nanostructure of SiO₂ aerogel and form a stable symbiotic skeleton. After that, we examined how the quantity of CNT doping affected the coating's surface morphology and photothermal properties. The findings demonstrated that the C-6 coating made from 0.6% CNTs performed best. Utilizing the photothermal effect of CNTs, it exhibited a steady rate of temperature increase and reached the target temperature of 153.4°C in 561 s upon near-infrared light (808 nm) irradiation. According to the results of experiments testing the photothermal performance, mechanical/chemical stability, and applicability of the coating, the coating has the advantages of being lightweight, provides quick de-icing, high stability, and simple production. This study not only increases the viability of using coating de-icing technology on wind turbine blades but also offers creative solutions to scientific investigation in the area of coating de-icing.

In the present study, silver nanoparticles were biosynthesized using banana (Musa spp.) peel extract as the reducing agent. The biosynthesized particles were then characterized using scanning electron microscopy, X-ray diffraction, transmission electron microscopy and Fourier transform infrared spectroscopy. Biosynthesized silver nanoparticles were then evaluated for their antibacterial activity against Gram-positive and Gram-negative cocci bacteria through agar diffusion study and minimum inhibitory concentration, and minimum bactericidal concentration was determined. Low density polyethylene film was coated with the biosynthesized silver nanoparticles following the dip coating method. The nanoparticle incorporated polymer films were then evaluated for antibacterial and antioxidant activity by agar diffusion studies, dynamic shake flask studies and 2, 2- diphenyl-1-picryl-hydrazyl-hydrate free radical scavenging assay, respectively. The surface characterization of the prepared films was also performed to ensure the presence of silver nanoparticle coating.

This paper presents novel organic–inorganic (hybrid) nanocomposite coatings (EASFs) containing a diamino diphenyl sulfone (DDS)-based structure with fluorine chains and SiO₂ networks. To obtain these nanocomposites, a diamino diphenyl sulfone (DDS)-based structure (SFDDS) containing silane terminated fluorine chains was synthesized. This structure was converted to a novel precursor (SFDDS precursor) by adding hydrolyzed tetraethoxysilane (TEOS) and trimethylsiloxy propyl methacrylate (MEMO) by the sol–gel method. This way, SFDDS precursor was obtained and incorporated into a mixture of epoxy acrylate and 1,6-hexanediol diacrylate reactive resin system in the range of 2.5–15%. The prepared solutions were spread onto low-carbon steel with a 75 μm wire-wound applicator instrument and cured by UV light. These coating samples were characterized in terms of their thermal, wear, physical, and corrosion properties. Considering physical properties, while hydrophobicity and scratch resistance presented substantial increases, adhesion and brightness properties decreased. The adhesion properties of EASF10 and EASF12.5 were fairly good, but their wear resistance values showed decreases at these adhesion levels. Glass transition temperatures increased with an increase in the SFDDS precursor content. This situation showed that these novel hybrid nanocomposite coatings could have higher thermo-mechanical properties. Besides these results, the corrosion resistance values of these novel hybrid nanocomposite coating materials were noteworthy. While the corrosion resistance results of these novel coatings were enhanced substantially in the air atmosphere, the NaCl atmosphere adversely affected corrosion resistance.

Graphical Abstract

Deterioration of steel infrastructures is often caused by corrosive substances. In harsh conditions, the protection against corrosion is provided by high-performance coatings. The major challenge in this field is to find replacements for the fossil-based resins constituting anticorrosive coatings, due to increasing needs to synthesize new environmentally friendly materials. In this study, softwood Kraft lignin was epoxidized with the aim of obtaining a renewable resin for anticorrosive coatings. The reaction resulted in the formation of heterogeneous, solid, coarse agglomerates. Therefore, the synthetized lignin particles were mechanically ground and sieved to break up the agglomerates and obtain a fine powder. To reduce the use of fossil fuel-based epoxy novolac resins in commercial anticorrosive coatings, a series of formulations were prepared and cured on steel panels varying the content of epoxidized lignin resin. Epoxidized lignin-based coatings used in conjunction with conventional epoxy novolac resin demonstrated improved performance in terms of corrosion protection and adhesion properties, as measured by salt spray exposure and pull-off adhesion test, respectively. In addition, the importance of size fractionation for the homogeneity of the final coating formulations was highlighted. The findings from this study suggest a promising route to develop high-performing lignin-based anticorrosive coatings.

Widely applied aluminum alloys in ship hulls, underwater vehicles, and marine machinery experience severe corrosion in harsh marine environments. For corrosion protection of aluminum alloys, the most convenient, effective, and low-cost approach was the application of anti-corrosion coatings. Coatings possessing self-healing properties to spontaneously repair damages have emerged as a research focus for new types of coatings. In this study, focused on the indication and repair of anti-corrosion coating damages for aluminum alloys, the fluorescent aggregation-induced emission (AIE) composite probe, rhodamine-naphthalimide (RNI), was synthesized, and the composite polymer materials HPPA-SMPU containing 2-hydroxyphosphinoyl carboxylic acid-doped polyaniline and shape memory polyurethane were prepared. Coaxial electrospinning technology was introduced to combine the two and create the fibrous materials with the fiber wall constructed from HPPA-SMPU, encapsulating the interior RNI solution. The fibers were incorporated into the epoxy coatings. RNI exhibited water-triggered AIE, Al³⁺-CHEF (chelation-enhanced fluorescence), and pH-responsive fluorescent properties to indicate infrared laser-targeted points of coating damages. The photothermal properties of HPPA-SMPU caused localized heating of the damaged coatings, reaching the phase transition temperature of epoxy and SMPU, leading to softening, expansion, shape memory behavior, and healing of the coating damages. The self-healing approaches enhanced the protective performance of the coatings for aluminum alloys, showcasing and extending the development of synergistic and intelligent functions in novel self-healing coating technologies.

Polydimethylsiloxane (PDMS) has been widely used to improve the antifouling properties of polyurethane (PU) coatings due to its low surface energy. Herein, a novel type of waterborne polyurethane (WPU) coating with good antifouling and self-healing abilities was synthesized by incorporating PDMS and disulfide bonds. The effects of PDMS and the disulfide content on the thermal, mechanical and surface properties of the coatings were investigated. Benefiting from a rational structural design, the obtained WPU coating manifested superior antifouling properties. In addition, the WPU coating exhibited good healing capabilities owing to the collaboration between dynamic disulfide bonds. Interestingly, the self-healing of an experimental crack occurred at a temperature above 60°C, and the coating recovered its mechanical properties to 95%. This finding has great significance for the design of multifunctional smart coatings for diverse applications.

Sulfonated β-cyclodextrin (CD1) combined with nanocurcumin or nanoclay was used to prepare multifunctional polyurethane (PU) coatings having antimicrobial capabilities. The combination resulted in formation of an inclusion complex which is confirmed by Raman studies and Job's plot analysis. The co-precipitation method is employed to achieve two inclusion complexes by combining CD1 with Cloisite 30B (C30B) and nanocurcumin (NC) separately. The resultant nanocomposite coating samples exhibit < 100 °C deviation at 50% weight loss from PU in heat resistance, as well as a 78% enhancement in toughness and 2.3–3 cm of zone of inhibition which is comparable to amoxicillin in its performance in resistance to bacterial growth. The advantage of absorbing such inclusion complexes into polymer coatings is the creation of multifunctionalities such as hydrophobicity, flame retardance, thermally stable and low intumescent coatings.

A sol–gel and phase separation method were employed to synthesize porous TiO₂ coating materials, which were applied to two types of transparent substrates. The coating preparation process is simple, cost-effective, and allows for the adjustment of pore structures. The study investigated the impact of the microstructure, substrate, and UV light exposure on the hydrophilic properties of the TiO₂ coating materials. The results indicate that the hydrophilicity of TiO₂ coating materials prepared with resin as the substrate is inferior to that of similar coatings prepared with glass as the substrate. Furthermore, the hydrophilic performance of glass substrates coated with porous TiO₂ is superior to those coated with dense TiO₂. Glass substrates coated with porous TiO₂ exhibit superhydrophilicity after 1 h of UV light exposure. The hydrophilic mechanism of the coating material surface was analyzed using surface energy theory, capillary theory, and photo-induced hydrophilic theory.