Progress in Organic Coatings最新文献

Organic polymers such polyacrylates, silicones have been used to protect stone-based heritages. However, polymers degrade obviously with time which may lead to secondary damages to heritages. Removal of previously applied but now degraded polymers on stone surface becomes necessary for the long-term preservation of stone heritages. Current cleaning protocol is mainly based on dissolving or extraction of aged polymers by organic liquid, whose kinetics is dominated by the slow diffusion and dissolving processes at the interfaces. Such cleaning process is very time consuming and becomes almost not applicable in large area cleaning. In this work, peelable PVA-borate hydrogels are developed. Organic solvents are introduced to tune gel's mechanical strength and its interfacial adhesion strength. Aged polymer coating can be removed easily by mechanical peeling when appropriate adhesion forces between the gel and aged polymer coating are achieved. Such cleaning protocol has been successfully applied on a fossil wall around 1200 m². Details, precautions and limitations of this protocol is discussed in this work.

Corrosion presents a substantial hurdle in the oil and gas industry, and corrosion inhibitors represent an economically viable strategy for control and prevention. As operating conditions in oil and gas extraction become increasingly harsh, factors such as cost, availability, and service temperature significantly influence inhibitor selection. While there is a wealth of literature on organic corrosion inhibitors, many exhibit a notable decrease in effectiveness at elevated temperatures, hindering their industrial application. To address this issue, we synthesized a novel Schiff base derivative, 1-((E)-(4-chlorophenylimino)methyl)naphthalen-2-ol (E4CMN), and investigated its effectiveness in inhibiting corrosion on Q235 immersed in a 1 M HCl. E4CMN adsorbs onto the surface by forming strong π-d interactions with Fe through the delocalized π electrons in its conjugated structure, effectively blocking the attack of corrosive particles towards the metal surface and consequently suppressing metal corrosion. Our study demonstrates that E4CMN exhibits maximum efficiencies of 96.9 % at a concentration of 250 mg L⁻¹. Importantly, E4CMN shows insensitivity to service temperature, maintaining an 84.4 % corrosion inhibition efficiency even when exposed to 75 °C. This work provides novel insights into mechanism of inhibition of mild steel corrosion by Schiff base derivatives in acidic environments and offers valuable considerations for the development and selection of corrosion inhibitors for high-temperature applications.

In this study, two essential oils (EOs) with preventive proved biocidal efficacy, namely oregano and eugenol, are encapsulated in silica nanocontainer, then dispersed in multifunctional, hybrid and nanocomposite coating. The aim of this work is to reduce toxicity of restoration materials, to avoid the chemicals dispersion in the environment and to extent stone protection treatments, preventing biofouling.

Composite silica nanocapsules, containing separately the two EOs, are prepared via one-step synthesis, based on oil-in-water miniemulsion polymerisation processes, and fully characterised by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and N₂ physisorption (BET/BJH). Micro-Raman spectroscopy (RS) and thermal analysis (TG/DSC).

In a second step, nanocomposite coatings, based on a flexible tetraethyl orthosilicate (TEOS) matrix, are synthesised dispersing TiO₂ nanoparticles and the two silica nanocapsules incorporating EOs. The coatings were applied on three different lithotypes samples of historical importance: brick, piperine and mortar. The effectiveness and compatibility of the coating formulation with the different stone substrates were assessed through a multi-analytical standard protocol.

The silica nanocapsules, show monodispersed spherical shape with size ∼110 nm, a core-shell structure, a BET surface area of 600–700 m²/g and high loading capacity.

The results on coatings characterisation show a crack-free and transparent structure. Moreover, the tests on applied coatings reveal the high hydrophobicity of the treated stone samples (static contact angle in the range ∼ 130–140° and reduction of liquid water capillary absorption 97–99 %) and unaltered permeability to water vapour (density of water vapour flow rate in the range 150–200 g/m²·d), demonstrating the suitability of the nanocomposite hybrid coatings for the application in stone protection against biodeterioration.

Copolymer thin films of isoprene with acrylic acid were synthesized using PECVD. In that way, the stretchable functionality of polyisoprene (PI) was combined with the hydrophilic functionality of poly(acrylic acid) (PAA) to obtain stretchable thin films with adjustable wettabilities. Deposition rates were found to change between 9 and 5.5 nm/min depending on the monomer flowrates. The analysis of water contact angle (WCA) values indicated that films having more AA units in their structures were more wettable. The stretchability of the films was assessed on laboratory gloves through stretch-release test and on PET sheet through bend-release test. No significant changes in the WCA values with no observable cracks and failures after successive tests were indication of stretchability of the copolymer films.

The UV curing method is free from volatile organic compounds (VOC) and exhibits high curing efficiency. However, pore flaws and inadequate mechanical qualities after cure greatly hinder their utilization in metal anti-corrosion. Herein, layered double hydroxides (LDH) supported by molybdic acid and cerium ions were synthesized in situ on the sericite (SC) surface, enhancing the shielding, corrosion inhibition, resin compatibility, and cross-linking density of the coating. Compared with carbon steel immersed in a 3.5 wt% NaCl solution, the incorporation of SC/KH560@LDH reduced the corrosion current density (I_corr) from 2.001 × 10⁻⁵ A/cm² to 7.883 × 10⁻⁶ A/cm². Moreover, the low-frequency impedance of the UV-SC/KH560@LDH coating remained high at 1.939 × 10¹⁰ Ω·cm² after 70 days of immersion in a 3.5 wt% NaCl solution. The excellent corrosion resistance of UV-SC/KH560@LDH can be attributed to the barrier properties of the filler, the chloride ion trapping, and the passivation effect. Furthermore, the UV-curable alkyd resin used in this work formed a chemical bond with the metal substrate, enhancing the mechanical properties of the coating. The adhesion strength of the UV-SC/KH560@LDH was measured at 11.50 MPa. The thickness loss (21.3 μm) of the UV-SC/KH560@LDH were minimal after 5000 cycles of wear. A new research concept for preparing the UV-SC/KH560@LDH with superior anti-corrosion and mechanical properties for carbon steel plate surfaces has been proposed to meet the demands of practical applications.

High-transparent material plays a pivotal role in optical engineering, yet faces practical challenges such as susceptibility to abrasion and ultraviolet degradation. To address these issues, we propose a simple approach for obtaining a multifunctional transparent polymethyl methacrylate. In this study, MWCNT@Fe₃O₄ was utilized as a hybrid core covalently bonded to a silane coupling agent, which was subsequently ion-exchanged with a surfactant to yield monodisperse MWCNT@Fe₃O₄ nanofluids. These nanofluids were then blended with polymethyl methacrylate through a simple casting process, resulting in a transparent composite material with good transparency (over 85 %), low friction (coefficient of friction < 3), UV resistance (UV absorption up to 73.35 %), and antistatic properties. The MWCNT@Fe₃O₄ nanofluids combine the benefits of liquid and solid lubricants by reducing the friction coefficient and enhancing the wear resistance of the composite material. Moreover, the fluidity of MWCNT@Fe₃O₄ nanofluids forms an anti-friction layer during friction, thereby improving the overall anti-friction properties of the composite material. Additionally, the hybrid core enhances the anti-ultraviolet performance of the composite film while the long chain lubricating layer improves its antistatic and antifouling capabilities. By incorporating MWCNT@Fe₃O₄ nanofluids as a filler, we have developed multifunctional transparent polymethyl methacrylate material that holds promise for advanced applications.

Innovative approaches to stone conservation materials are essential for addressing the challenges of preserving cultural heritage while meeting environmental and sustainability standards. Based on this premise, this study delves into the synergy between sol-gel processes and nanotechnology to develop advanced epoxy-silica hybrid materials tailored for stone conservation. This investigation specifically targeted the use of amino-functionalized mesoporous silica nanoparticles (NH₂-SiO₂ NPs) as interactive carriers for natural phenolic biocidal compounds within advanced sugar-based hybrid, demonstrating significant potential in the field of stone conservation. The novel products exhibited improved multifunctional properties attributed to the surface-modified NPs, which facilitated their intimate incorporation into the hybrid network. This integration promoted the creation of homogeneous materials with adapted flexibility, particularly critical for thermal expansion effects, and ensuring mechanical integrity even in outdoor environments. Furthermore, the encapsulation of natural biocidal compounds such as carvacrol and curcumin addressed their intrinsic drawbacks of volatility and coloration effects, preserving their efficacy while minimizing also plasticizing adverse effect on base thermoset. Indeed, the inclusion of curcumin-loaded NH₂-SiO₂ as dual bactericidal system provided the most favorable compatibility in terms of thermo-mechanical behavior. This system exhibited thermal resistance up to 350 °C and featured inter-joined flexible crystalline domains, distinguished by glass-transition temperatures of 67 and 99 °C. Furthermore, it exhibited enhanced hydrophobic properties reaching contact angles of 105°, and showcased an optimal live/dead ratio response against bacteria. The laboratory scale testing demonstrated a balanced set of features with significant capabilities in both recovering and maintaining the integrity of the lithic substrate, against common degradation patterns induced by prolonged acid exposure.

Currently, an increasing number of studies focus on the applications of hydrophobic surfaces for underwater drag reduction. However, the drag reduction mechanisms of hydrophobic coatings with controllable wettability still lack systematic understanding. Herein, nano-SiO₂ composite coatings with different contact angles were fabricated using air spraying techniques. The relationship between the hydrophobicity of these coatings and their drag reduction performance under different Reynolds numbers was further investigated. The results showed that the uniformed distributed air layer and low depinning force significantly contributed to drag reduction performance. The coating with a contact angle of 140° achieved a maximum reduction rate of 58 % at a Reynolds number of 750. However, the coatings with contact angles of 150° and 155° exhibited diminished drag reduction effects due to the uneven distribution of the air film. This study highlighted that the hydrophobicity of the coatings and the uniform microstructures are essential for sustaining effective drag reduction performance.

Influenced by pitcher plants, the creation of a novel biomimetic surface–possessing non-wetting, robust, and durable, coupled with intelligent reversibility–holds significant potential for widespread applications in revolutionizing metal corrosion protection. This study utilized a combination of in-situ growth and chemical modification techniques to achieve slippery liquid-infused porous surfaces (SLIPS) with biomimetic properties on MgLi alloy surfaces exhibiting a water contact angle of 122 ± 2° and a sliding angle of 6 ± 2°. The resulting SLIPS possessed antifouling, self-cleaning, self-healing, impact, durability, and corrosion resistance, as well as bonding to the substrate. The coating offered a multifunctional protective barrier for MgLi alloys, which could skillfully reverse superhydrophobicity and slipperiness as needed, augmenting the corrosion resistance of MgLi alloys while broadening their potential applications. Simultaneously, the formation mechanism of the prepared coatings was discussed in-depth. Notably, there is a scarcity of reports on the corrosion protection of MgLi alloys by SLIPS. The as-prepared SLIPS coating can also be extended to protect other materials, fulfilling novel needs in diverse fields such as biomedical fluid handling, antifouling, and self-cleaning windows.

Questions remain about the unreasonable collocation of Ti₃C₂T_x and nanocontainers resulting in the performance degradation of multi-function Ti₃C₂T_x-based epoxy composite coating. Here, mesoporous SiO₂ nanocontainers (SNT) containing both potassium thiocyanate and hexadecyl trimethyl ammonium bromide (CTAB) were loaded on MXene-based platform (SNT-on-MP) to achieve a novel epoxy coating (SNT-on-MP@EP) with the integrated functions of self-warning, self-healing, anti-corrosion and anti-wear. In the damaged area, the thiocyanate groups combined with Fe³⁺ ions to form a blood-red color display, and the formed coordination compound and CTAB as corrosion inhibitors were deposited on the metal substrate, thus showing intelligent response function. Besides, because of passive and active synergistic protection functions, the lowest-frequency impedance value of SNT-on-MP@EP maintained 5.74 × 10⁷ Ω·cm² after 4 weeks of exposure in salt water environment, which was increased by two orders of magnitude compared with pure epoxy coating. Under the reciprocating sliding friction, the wear rate of SNT-on-MP@EP reached 5.32 × 10⁻⁵ mm³/N·m, and was reduced by 58.29 %, owing to the formation of lubricant film at the friction interface and the enhancement of the deformation resistance of the coating. The reasonable collocation of SNT and Ti₃C₂T_x-based platform eliminated the problem of weak interaction between traditional inorganic nanocontainer and water-based epoxy coating, thus giving full play to the advantages of both.