Journal of Coatings Technology and Research最新文献

Fingerprints have been established as legitimate and critical forensic science evidence for identifying criminals beginning as early as the twentieth century. This article details the different types of fingerprints, the broad range of surfaces, and various development techniques available for on-site latent fingerprint collection, with fingerprint fidelity being of prime significance. Fluorescent imaging of latent finger-marks benefits from enhanced sensitivity, selectivity, and reduced reliance on instruments. The review focuses on the topical developments reported on small-molecule organic fluorophores which could be used to develop latent prints through powder, solution, and fuming approaches. These inexpensive luminophores extend wide emission profiles that span the visible spectrum to visualize the latent prints with exceptional resolution, free from any interference originating from the background surface. Further, the critical challenges and prospective scope for future research developments to improve the detection of latent fingerprints using small-molecule fluorophores are also discussed.

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In recent years, polymer science has undergone significant advancements, resulting in the creation of materials with enhanced properties and a diverse range of applications. A noteworthy development in this field is the rise of "hyperbranched resins," characterized by intricately branched three-dimensional structures that represent an exciting frontier in polymer science. This article conducts a comprehensive examination of the resurgence of interest in alkyd resin synthesis, focusing on the horizon of hyperbranched modification and advancements. It delves into the distinctive mechanical, thermal, and chemical properties of these resins. Furthermore, the article explores potential applications across various industrial sectors. The content is grounded in a meticulous review of current scientific literature and is reinforced by relevant references.

The thermoelectric properties of fully sprayed thin films of poly(3-hexylthiophen-2,5-diyl) (P3HT) doped with chloroauric acid are investigated for different film thicknesses. The film thickness increases logarithmically with increasing amount of deposited material on the surfaces. Both the electrical conductivity and measured Seebeck coefficients of the doped thin films show an optimal polymer layer thickness between 275 and 310 nm and yield a maximum power factor of ((1.77,pm ,0.22) frac{mu text {W}}{text {m}cdot text {K}^2}). The optimum layer thickness results from the optimal amount of dopant molecules per monomer between 1.1 and 1.3 at these ratios of P3HT and HAuCl(_4) for the thin film fabrication.

In this study, two indigenous Ethiopian medicinal plants, namely R. prinoides and C. macrostachyus, were applied into gauze cotton fabric for the first time by pad-cure-dry method, using citric acid as a crosslinker. Various extract concentrations (3%, 5%, and 10%) were applied to fabric to assess their bacterial efficiency against S. aureus and E. coli. Furthermore, an evaluation of the in vitro cytotoxicity and release study, water absorbency, stiffness, and tensile properties were conducted. The incorporation of plant extract into fabric was confirmed through scanning electron microscopy and Fourier transform infrared spectroscopy analysis. The findings of the investigation revealed that a fabric treated with 10% R. prinoides leaf extract exhibited inhibition zones of 8.2 mm against S. aureus and 6.75 mm against E. coli, whereas 10% C. macrostachyus leaf extract treated fabric showed inhibition zone of 5.4 and 2.42 mm, respectively. Fabrics treated with concentrations lower than 10% of the extract in an in vitro study exhibited nontoxic effects, leading to an increase in cell viability rates for both plant extracts. After 48 h, treated fabrics exhibited a release of 73.3%, 75.9%, and 81.8% for R. prinoides leaf extract and 58.3%, 66.1%, and 77.8% for C. macrostachyus extract treated with 3%, 5%, and 10% concentrations, respectively. Furthermore, the plant extract treated fabrics showed an improvement in water absorbency and fabric stiffness. However, statistically, the plant extract concentration has no effect on fabric tensile strength. Generally, an increase in the concentration of plant leaf extract leads to enhanced antibacterial properties, water absorption, and softness.

In recent studies comparing the outdoor weathering of poly(vinylidene fluoride) (PVDF)-based coatings against several accelerated weathering test cycles, including ASTM D7869-13, we found all the cycles accurately reproduced Florida rank order gloss and color retention trends for PVDF-based coatings made with single (non-TiO₂) pigments. However, none of the cycles accurately predicted the rank order of rutile TiO₂ grades for Florida gloss retention, nor the magnitude and direction of color fade in organic pigment/inorganic pigment blends. This paper follows up on these earlier studies, to examine whether the ASTM D7869 cycle might nevertheless have some utility for industry standard or specification purposes, across resin lines. We report for the first time the results of two recent studies comparing ASTM D7869 and South Florida weathering, for a range of weatherable binder chemistries commonly used in industrial coatings, and specifically examining color-matched, non-white colors. The data suggest that ASTM D7869 testing for 5000–6000 h might be a promising way to gauge the weatherability of coatings intended to meet 5-year South Florida weathering requirements. At the same time, the data also suggest that the ASTM D7869 cycle would be unreliable for predicting the weatherability of coatings intended to last 10 years or even much longer, within a 6–12-month timeframe, due to issues with false positives. For this reason, in the new SSPC Paint 47 fluoropolymer topcoat standard, a more aggressive UVB-313 fluorescent cabinet cycle was chosen, due to its ability to give results in 6 months, with a very low level of false positives.

Although water-based paint is increasingly being advocated as environmentally friendly, it is more susceptible to biodeterioration during processing, preparation, and storage. Therefore, sufficient proactive measures are urgently needed to control and prevent microbial contamination along the production chain. The experimental setup comprised the investigation of the paints (e.g., pH, water content, FTIR) as well as the isolation and identification of bacterial and fungal contaminants via Sanger sequencing and MALDI-TOF MS. We identified well-known paint degraders such as Bacillus and Pseudomonas spp., however also less frequently abundant species like Rhodococcus. While the diversity within gram-negative bacteria turned out to be higher compared with gram-positive ones, the latter were predominant in paint and their immediate ambience, indicating that they are more resistant toward the applied measures. Our results emphasize the need for manufacturers to apply tailored measures against paint spoilage as a prerequisite for further product- and production-specific preservation concepts.

When paint is applied to a substrate, the formation of paint craters is generally due to dewetting caused by a low surface energy substance present, such as siloxanes or perfluorocarbons, either on the substrate or in the paint that is applied to the substrate. As paint cratering is a surface phenomenon, the causing chemicals can be minimal both in size and quantity, or more precisely, below the detection limit of many analytical techniques. In order to identify the chemical responsible for paint craters, a technique that is extremely surface sensitive, chemically selective and capable of imaging is required. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) perfectly fits all these analysis requirements, and for the past decade we have used ToF-SIMS to identify automotive paint cratering chemicals. This article categorizes the paint cratering chemicals for the past decade and their distributions in terms of the four seasons. The information presented is expected to benefit both painting engineers and defect analysts in understanding possible/potential chemicals causing automotive paint craters, which is a costly failure in car manufacturing.

The present paper describes the design of a superhydrophilic self-cleaning surface using mixed metal oxides. SiO₂/ZnO/TiO₂ layers were deposited on a cleaned glass surface by a dip coating method. The silica layer imparts stability and adhesion to the coating of the glass surface. ZnO was deposited in the form of nanoflowers over silica which was further coated by titania nanoparticles in a multilayer. This renders the exposed titania layer to be superhydrophilic having a contact angle of eight. High surface area combined with superhydrophilicity helps impart enhanced photocatalytic activity of the coating due to increased wetting characteristics of the surface. The surface, therefore, acts as a self-cleaning surface by effectively degrading pollutants. Moreover, the formation of a heterojunction between ZnO/TiO₂ layers reduces the band gap to 2.98 eV from 3.59 eV in TiO₂ thus enabling the degradation of pollutants in the visible range (416.25 nm).

Hybrid yarns, combining stainless steel with glass fibers, are promising for impact-resistant composites. Inside the yarn, the thermoplastics matrix is provided in the form of endless filaments. Thermoplastics gained popularity as composites' matrix due to recyclability. The study emphasizes customizing adhesion between stainless steel and polypropylene for desired properties in the composites. Tailored adhesion is crucial for optimizing the performance of stainless steel/polypropylene composites. Within this contribution, a selection of adhesion promoters and preventers is analyzed to generate adjustable adhesion between polypropylene matrix and stainless steel filaments. The characterization is fulfilled using contact angle measurements on films of coating agents and coated stainless steel filaments. Furthermore, surface free energy is calculated and theoretical adhesion is analyzed between coating agent and stainless steel filaments and coated stainless steel filaments and polypropylene matrix. The results are validated by single fiber pullout tests.

This study presents the synthesis and characterization of novel lanthanide complexes, specifically La (III) and Gd (III), designed as flame-retardant additives for paint formulations. The complexes were synthesized and thoroughly characterized using different spectroscopic techniques, complemented by density functional theory computational calculation insights. The resulting La (III) and Gd (III) complexes were then incorporated into paint formulations, and the physical properties of the modified coatings were systematically evaluated. Ignitability and the minimum oxygen percentage required for sustained combustion were quantified according to standardized procedures. The modified coatings demonstrated enhanced mechanical and ignition properties in comparison to blank samples. The limiting oxygen index (LOI) values were notably higher, underscoring the efficacy of the lanthanide complexes as flame retardant additives. La complex led to an ignition time of 850 s and an LOI of 40, while Gd complex resulted in the same ignition time of 850 s and LOI of 50 compared to the uncoated sample of 550 s and an LOI of 16. The mechanical properties of the painted samples, engineered with the inclusion of these prepared metal complexes, exhibited a significant improvement. This comprehensive investigation provides valuable insights into the potential application of lanthanide complexes as effective flame-retardant additives in coatings, offering a promising avenue for enhancing the safety and performance of various materials.