Journal of Coatings Technology and Research最新文献

Numerous studies have discussed the impacts of VOCs emissions from coatings on ground-level ozone in China. However, the VOCs contents and species of housing refurbishment coatings need to be further investigated to understand the potential contribution of VOCs to air pollutants and health risks. This study has collected 78 representative coating samples from e-commerce platforms and local building material markets according to typical Chinese consumer behavior. The VOCs compositions of those coatings have been identified by gas chromatography and compare with the limit values in compulsory national standard of industrial protective coating. The analyses suggest that multiple-use housing refurbishment coatings are remarkably higher in contents of total VOCs and PAHs than traditional industrial coatings. VOCs contents and species in coatings vary by both package and solvent categories. Solvent-based coatings tend to have higher VOCs than waterborne coatings, while the VOCs contents in spray can packages are greater than those of bucket packages. Among solvent-based coatings, benzene derivatives are in full compliance with the ceilings, but 40–60% of samples have PAHs contents exceeding those in general industrial coatings. To investigate further potential of VOCs abatement, systematic administrative efforts should be taken. Multiple-use housing refurbishment coatings need to be considered as a distinctive type of coating in standards, and VOCs content limits should be set with a balance between film qualities. Afterward, the transparency and publication of VOCs and species contents of the domestic users are the keys to compel coating manufacturers to lower VOCs contents and adjust formulations at the national level.

Two different dispersion techniques, namely ball milling and sonication, were implemented to prepare PEEK/1.5 wt% ceria nanopowders, which were deposited using an electrostatic spraying technique on mild steel substrates (post-heat treatment of the coated sample @370 ºC for 30 min). It was observed that the ball-milled powders failed to form a coating whereas the sonicated powders resulted in a coating of ~ 95 µm thickness. To investigate the reasons for this varying behavior, the ball-milled and sonicated powders were characterized by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) to evaluate their physical and chemical properties. XRD results revealed that the sonicated powders retained a higher crystallinity (~76.46%) as compared to the ball-milled powders (~66.84%). FTIR analysis indicated uniform dispersion of ceria nanoparticles in sonicated powders. TGA showed that the sonicated powders had better thermal stability than the ball-milled powders at higher temperatures. However, an increase in the post-heat treatment time for the ball-milled powders to 90 min did result in a coating of ~ 98 µm. Hence, tribological characterization of the coatings was conducted using a ball-on-disk configuration at a load of 70 N for 10,000 cycles at 0.4 m/s, which resulted in the failure of the coatings deposited from the ball-milled powders after 2500 cycles as compared to the nonfailure of the coatings deposited from the sonicated powders even until 10,000 cycles.

Here, in order to overcome the drawbacks of carbon spheres (CS) as a single additive with high smoke emission and limited thermal stability, we constructed a highly flame retardant carbon sphere composite (CS/PCP) with C-N-P structure by chemically bonding hexachlorocyclic triphosphate (HCCP) to the surface of CS using polydopamine (PDA) as the linking medium. Moreover, the TA-Fe complex layer was uniformly wrapped around the surface of CS/PCP to obtain CS/PCP@TA-Fe composite flame retardant. The complex flame retardant additives obtained were used for the improvement of thermal insulation properties of waterborne epoxy coatings. Fire resistance tests show that the CS/PCP@TA-Fe nanomaterials enhance the thermal insulation of EP to a minimum of 171.5 °C on the backside of the samples, providing support for the high thermal insulation performance. In furnace tests, the CS/PCP@TA-Fe/EP composite coating demonstrated the highest swelling height (20.2 mm) and the largest swelling n rate (15.66), far exceeding other coatings. Besides, the CS/PCP@TA-Fe/EP composite coating obtained the largest carbon residue (28.5%) due to the metal promoting the production of carbon. Observation of the carbon surface of the CS/PCP@TA-Fe/EP composite coating after combustion revealed that the residual carbon was dense and intact compared to that of the other coatings, indicating that it could effectively inhibit the entry of heat. Therefore, the successful development of this nanocomposite fire retardant coating contributes to the further development of waterborne epoxy intumescent fire retardant coatings.

Since the main solvent of waterborne polyurethane (WPU) is water, its water resistance is poor. Additionally, the low oxygen index of WPU adhesive films limits their flame-retardant efficacy as coatings, thereby restricting their application scope. To address these limitations, this study independently modified the hydrophobicity and flame retardancy of WPU. First, a cyclophosphonitrile derivative (HCCP-6) was synthesized as a flame retardant. Flame-retardant WPU (NPWPU) was then prepared by reacting the –NH₂ group of HCCP-6 with the –NCO group of a polyurethane prepolymer, incorporating the flame-retardant properties into the WPU polymer chain via free-radical grafting. Next, hydrophobic F-SiO₂ suspensions were prepared and combined with NPWPU emulsions of varying concentrations. The mixtures were sprayed onto cotton fabrics using an airbrush to produce waterproof, flame-retardant polyurethane-coated textiles. Results demonstrated that NPWPU/F-SiO₂-coated cotton fabrics exhibited water contact angles exceeding 150°, indicating excellent hydrophobicity. These fabrics also showed increased char residue, reduced total heat release, and suppressed smoke production. This performance stems from the synergistic flame-retardant effect of nitrogen (N) and phosphorus (P), coupled with the high-temperature resistance of SiO₂, which promotes char formation, shields the material’s inner layers from thermal degradation, and enhances overall flame retardancy.

Using petroleum-based plastic materials poses many serious problems, including resource consumption and environmental pollution. Paper-based materials are good substitutes for plastic products because of their biodegradability, resource-richness, and recyclability. Paper’s poor water and oil resistance limits its wide application in food packaging. The use of water and oil repellents is an effective strategy to improve the barrier properties of paper. However, fluorine-containing oil repellents produce perfluorooctanoic acid/perfluorooctanesulfonyl compounds (PFOA/PFOS), which are hazardous to human beings and the environment, during the preparation and use of the repellents. Therefore, developing non-toxic, harmless, and biodegradable bio-based waterproof and oil-resistant coatings is the mainstream trend in the future. In this study, simple and environmentally friendly fluorine-free waterproof and oil-resistant coatings for food wrapping paper were developed by grafting oleyl alcohol onto chitosan using the ring-opening reaction of epichlorohydrin, and the reagents successfully adhered to the surface of the paper. The successful synthesis of waterproof and oil-resistant coatings was confirmed by nuclear magnetic resonance (NMR) and infrared (IR) analyses. The chitosan-based coatings (CHI-g-xOA, x = 1/8, 1/4, 1/2, 1) with different oleyl alcohol contents were prepared by the facile method. The obtained coated paper CHI-g-xOA-p (x = 1/4) has not only excellent oil resistance (Kit rating value of 11 ± 1.0/12), which meets the food-grade oil-proof requirement, but also has excellent water resistance (Cobb 60 value of 11.86 ± 1.60 g/m²). Compared with the uncoated paper, the tensile strength and water vapor transmission rate of the coated paper were significantly improved.

Marine biofouling poses a significant global challenge, inflicting extensive damage on offshore structures and vessels, leading to substantial economic losses and environmental issues. Antifouling coatings have emerged as a primary solution, as they can form a long-lasting protective layer on surfaces, offer cost-effectiveness, and have a broad application range. Early developments in antifouling coatings included biocide-containing formulations, which effectively controlled biofouling but resulted in extensive non-target mortality, presenting enduring threats to human health and marine ecosystem stability. This has underscored an urgent need for eco-friendly, high-efficiency antifouling solutions. Despite the variety of approaches studied, a comprehensive solution to marine biofouling using coatings remains elusive. Therefore, the advancement of antifouling coatings continues to be a focus of ongoing research. This review synthesizes current findings, concisely outlining the adhesion mechanisms of marine biofouling organisms and key performance parameters for evaluating antifouling coatings. It also reviews the development status of major antifouling coating types and proposes future directions for antifouling coating research.

Soy protein isolate (SPI), an abundant, cheap, and renewable industrial raw material, is an eco-friendly alternative to fossil fuels. However, the poor mechanical properties and high water sensitivity of SPI films limit their practical application. In this study, biodegradable films were prepared by using soybean protein isolate (SPI), glycerol, nano-zinc oxide (ZnONPs), and trimethylol propane triglycidyl ether (TMPGE) as raw materials, and the physical properties, chemical structure, thermal stability, and morphology of the composite films were fully analyzed. The effects of ZnONPs and TMPGE on the properties of the films were studied by FTIR, SEM, XRD, and TGA. The results showed that compared with the unmodified SPI film, the tensile modulus and tensile strength of TMPGE-modified film were increased by 32.42% and 44.77%, respectively, and the water content and water absorption were decreased by 16.33% and 79.33%, respectively, which can effectively prevent the swelling of SPI film due to the formation of a chemical crosslinking network between SPI, M-ZnONPs and TMPGE. After modification, the composite films also displayed good antibacterial activity against E. coli and S. aureus and showed broad development prospects in making green food packaging.

The present paper describes the influence of various types of expandable graphite on the fire-retardant properties of intumescent coating based on PVC binder. The optimal content of the expandable graphite required to achieve maximum fire protection efficiency was determined by incorporation of different amount of expandable graphite (5%, 11%, 18%, 22.5%, and 28%) to the intumescent fire-retardant coatings. The degree of expansion and fire protection efficiency of coatings were measured. TGA was performed to investigate the obtained coatings. The coatings were applied to steel I-beams and subjected to a standard fire test to assess their fire protection efficiency in terms of time. The use of expandable graphite derived from graphite nitrate and graphite bisulfate, along with their modifications with phosphorus(V) oxide as intumescent agents in fire-retardant PVC compositions, exhibited varying effects on the thermal behavior of the coatings. The test results revealed that coatings based on expandable bisulfate graphite demonstrated a higher degree of expansion and superior fire-retardant properties compared to those based on expandable nitrate graphite. Additionally, the presence of P₂O₅ in the expandable graphite formulation acted as an anti-oxidizing agent, contributing to an increase in non-combustible residue when exposed to heat, and consequently enhancing the overall fire-retardant efficiency of the coatings.

Nitrocellulose (NC) is a well-known binder for economic coating formulation. However, it is only available in solventborne systems. In this work, a waterborne alternative based on NC nanoparticles will be investigated. Starting from a precipitation process using water, nanoparticles are prepared from a solution of NC in ethanol and acetone. The resulting aqueous dispersions contain highly uniform, self-stabilized nanoparticles and show the typical characteristics of NC. Various coalescing agents are investigated to understand the specific mechanism of film formation. Apparently, the nature of the coalescing agent is crucial for the formation of smooth surfaces after drying of the dispersion. The mechanism of coalescence is investigated on the microscopic scale. It is assumed to be different from a classic coalescence process, and appears as a hybrid version between a water- and a solvent-based coating. In the end, water-dilutable formulations are achieved, revealing a reduced VOC-content by 75%, compared to common solventborne NC-systems.

Bioinspired coatings have significantly contributed to combating microbial contamination involving fungi, bacteria, and viruses. Building on these advancements, we propose a new approach using additive manufacturing (AM) techniques through high-resolution 3D printing (MSLA) to develop chemically active–passive printable hybrid material. We explored a bioinspired design based on the micropapillae found on the inner surface of the Huernia penzigii flower, aiming to tune the wettability of the surfaces as a function of the aspect ratio of the printed bioinspired microstructures. This creates a hydrophilic regime that induces contaminated droplets to approach and interact with the active surface, which is based on a photocurable copper nanocomposite. This printable material was characterized using FTIR, UV-Vis, XRD, SEM analyses, and contact angle measurements. Through a proof of concept, we were able to establish a correlation between the contact angle and the size ratio of bioinspired micropapillae from H. penzigii. For micropapillae tuned to a height of 400 µm, we observed the contact angle reduce to 38°, indicating that the tuning of the contact angle in the bioinspired active–passive hybrid structure may be a good strategy to induce more significant droplet interaction to enhance the antiviral activity of the surfaces and combating contamination through fomites.