Journal of Coatings Technology and Research最新文献

The advancement of UV-curable coatings derived from renewable resources is of paramount importance in achieving sustainability goals for safeguarding the environment. This study aims to synthesize novel UV-curable reactive diluent by reacting bio-based adipic acid with diethanolamine, followed by functionalizing it with glycidyl methacrylate. UV-curable bio-based oligomer was prepared by a ring-opening reaction of epoxidized castor oil with acrylic acid. The chemical structures of the resulting reactive diluent and oligomer were confirmed using analytical techniques such as end-group analysis, FTIR, and 1H NMR. A series of bio-based UV-curable formulations were prepared by combining synthesized reactive diluent with the oligomer and applied on wooden substrates. The effect of incorporating different concentrations of synthesized reactive diluent ranging from 10 to 40 wt.% on the viscosity of the synthesized oligomers was investigated by studying their rheological behavior. The UV-cured coatings were further evaluated for their extent of curing, bio-content, acid, alkali, and boiling water resistance. Thermal properties of films were further characterized for TGA and DSC. Cured coating with 40 wt.% reactive diluent exhibited 86 gloss at 60°, 5H hardness, 5B adhesion, 81.27 °C glass transition temperature, and maximum thermal decomposition temperature of 454 °C. The cured coatings have shown impressive stain resistance properties.

Graphical abstract

To overcome the main challenge of low colloidal stability of poly(styrene-co-butyl acrylate-co-acrylic acid-co-acrylamide) latexes in the presence of polymerizable surfactants, this study aimed to obtain latexes with superior properties and coagulum-free through semibatch emulsion polymerization using anionic and nonionic polymerizable surfactants (Maxemul^TM 5010 and Maxemul^TM 6106) mixed with a conventional anionic surfactant (Dowfax^TM 2A1). The effect of the surfactant amount and type on the colloidal stability, particle size, electrolyte stability, water absorption of the polymer films, and wet scrub resistance of the paint films were investigated. The water absorption of polymer films containing a blend of polymerizable and conventional surfactants was compared to that of films containing conventional surfactants. The results showed that the molar mass has a significant impact on latex stability during the early stages of polymerization. By incorporating a chain transfer agent (n-dodecyl mercaptan, DDM) within the range of 0.05-0.2 wt% loaded in the reactor charge based on the total formulation, coagulum-free latexes were obtained. When polymerizable surfactants were used together with a conventional surfactant and DDM, stable latexes with particle sizes ranging from 96.5 to 110.0 nm, enhanced film properties, and better scrub resistance of the paint films were obtained. The increase in polymerizable surfactant improves the electrolyte stability of the latexes but increases the water absorption of the polymer films. The use of polymerizable surfactant helps to reduce the total amount of surfactant used in the latex formulation. The results achieved in this study create a new approach for the synthesis of poly(St/BA/AA/AM) latexes using polymerizable surfactants for highly pigmented architectural paints.

Glass fiber reinforced plastics (GFRP) are essential for lightweight design and are manufactured in high quantities. Since there is no suitable method for recycling, the GFRP are mostly grinded and used as filler at end of life. In this work, the well-known principle of debonding on demand is considered to enable feasible and value-retaining separation of glass fibers from the polymeric matrix. To this end, gas-releasing thermo-responsive substances (TRS) like carboxylic or amino acids are introduced to the composite to investigate their potential for causing delamination after heating. To promote sufficient fiber/matrix adhesion, the TRS are encapsulated with silica or immobilized on magnetite particles. Furthermore, the immobilization synthesis is scaled up by using a custom-made continuous flow reactor. Finally, a new sizing mixed for glass fiber spinning, containing the particles, is formulated. The experiments reveal that a maximum of 0.5 wt.% particles can be used in the sizing to coat the fibers. Although all tested samples show a significant organic functionalization, the particles functionalized with TRS do not trigger sufficient delamination at the current state of development.

Organic–inorganic hybrid (OIH) coatings and thin films have been established as advanced materials owing to their unique combination of properties suitable for many current and emerging end-use applications. The difficulties in the deposition of such films under desirable cure conditions limit their application space. This study presents the development of a new generation of functional oligomers designed to cure independently under various cure conditions to produce OIH coatings. Specifically, we have meticulously designed and synthesized a high-solid organosilane oligomer with polyurethane backbone structure and alkoxysilane functionality. This study investigates high-solid OIH coating systems comprised of organosilane oligomer, alkoxysilane reactive diluents, and a diverse range of blocked catalysts for their effectiveness in curing under thermal, UV exposure, and ambient temperature conditions. Furthermore, we have explored the potential to combine these curing processes, offering the coating system with plural-cure capabilities. FTIR spectroscopy has been used to track the extent of cure by tracking relative intensities of alkoxysilane groups before and after curing. A comparative analysis of coatings cured by various techniques provided valuable insights into the underlying curing mechanisms and their impact on film properties. The outcome of this study suggests that these new generation versatile OIH coatings systems can be excellent candidates for sustainable advanced coating applications.

Reverse osmosis (RO) membranes have been widely used in seawater desalination and drinking water preparation due to their outstanding ability to retain low valence salt ions and large organic molecules. Small neutral molecules (SNMs) are widely present in water, typically represented by boric acid in seawater and urea in wastewater. Reducing SNMs to meet drinking water standards is a new challenge for RO membranes. In this study, we developed a thin-film composite RO membrane tailored for seawater desalination, demonstrating exceptional selectivity against SNMs and heightened permeability. Specifically, a nonionic surfactant, flexible polyisobutylene succinimide (PIBSI), was added into the organic phase to react with trimesoyl chloride (TMC). The results showed that the new product, PIBSI–TMC, effectively exhibited the dual function of surfactant and co-monomer changed the physicochemical structure of PA formation during the interfacial polymerization process based on the detailed characterization. PIBSI integrated into the PA matrix significantly enhanced the hydrophobicity of the membrane surface and increased the specific surface area. Simultaneously, the pore size within the layer was reduced, and defects on the RO membrane surface were filled. The objectives were achieved by enhancing the size exclusion mechanisms effect, reducing SNMs diffusion rate, and ultimately improving selectivity. Experimental results demonstrated that the novel membrane achieved excellent desalination performance and a maximum boron removal efficiency of up to 90.40% in simulated seawater (32000 ppm NaCl, 5 ppm boron) compared to virgin membrane. The produced freshwater meets drinking water standards in various regions. Additionally, it exhibited higher flux (48.0 L m⁻² h⁻¹, 55.0 bar, approximately 26.4% permeate flux decline) compared to similar membranes. In addition, the rejection of SNMs in wastewater represented by urea was also effective. Therefore, it is favorable for application in resource recovery and pollutant removal. In conclusion, this novel RO membrane holds broad prospects for applications in seawater desalination and potable water production.

Graphical abstract

Herein, a simple and efficient inorganic particle surface modification strategy was developed to improve the flame retardancy of flammable polyurethane (PU) materials while avoiding the serious degradation of their mechanical properties due to the incorporation of inorganic particles. Novel organic–inorganic hybrid hydroxylation ammonium polyphosphate (OHAPP) was fabricated via an ion-exchange reaction between APP and diethanolamine, and a PU/OHAPP film was prepared by crosslinking OHAPP with reactive PU via in situ polymerization. The curing properties, flame retardancy, and mechanical properties of materials were evaluated. Results showed that the addition of 15 wt% OHAPP in PU increased the tensile strength of the sample by 16% compared to PU alone. The peak heat release rate, total heat released, and total smoke produced from the materials measured via the conical calorimetric method were 337.2 kW/m², 78.1 MJ/m², and 8.9 m², respectively, which were 63.8%, 43.6%, and 15.2% lower than those of PU. Additionally, the flame-retardant mode of action of the PU/OHAPP film was verified. This study is a useful reference for further studies on flame-retardant materials.

Monoclinic bismuth vanadate (BiVO₄) as an environmentally friendly bright yellow pigment has received increasing attention over the past two decades. Unfortunately, poor thermal stability and acid resistance hinder its large-scale application in the industrial field. Herein, multicoated BiVO₄@SiO₂ yellow pigments with enhanced thermal stability and acid resistance were successfully synthesized by the hydrolysis method. The effects of process parameters such as Si/Bi molar ratio (n_Si/Bi), water bath temperature (T_b), and dropwise addition rate of water (V_d) on the preparation of BiVO₄@SiO₂ yellow pigments were systematically studied. The temperature stability of once-coated BiVO₄@SiO₂ encapsulation pigments prepared under optimized conditions can be increased from 620 to 860°C. To further improve its thermal stability and acid resistance, the BiVO₄ pigments were wrapped multiple times and its temperature and acid resistance were evaluated. The results showed that after three times wrapping, the obtained BiVO₄@SiO₂ showed optimal thermal stability and could maintain yellow color at 1200°C. The high-temperature stability and antiacid corrosion highlight the promise of its potential for commercial yellow pigments.

In this study, we present a method to enhance the hydrophobic properties of organofluorosilicon styrene–acrylate emulsions while simultaneously reducing their environmental pollutional, and assess their potential for applications in oil–water separation materials, waterproof coatings, and related fields. We achieved this by developing organofluorosilicon styrene–acrylate emulsions with core–shell interpenetration properties through a meticulously designed preemulsified semicontinuous seed emulsion polymerization process. In addition, we have added sodium lignosulfonate, a green and renewable material, to the polymerization process to further enhance the environmental sustainability of these emulsions. A comprehensive characterization of the lignin-modified emulsions was conducted using various techniques, including assessments of storage stability, centrifugal stability, ionic stability, water contact angle, thermogravimetric analysis, Fourier transform infrared spectroscopy, as well as scanning and transmission electron microscopy analyses. The findings revealed that the lignin-modified emulsions exhibited similar stability to conventional phenylpropylene emulsions in terms of Ca²⁺, mechanical, and storage stability, while demonstrating notably enhanced thermal stability and hydrophobicity. Significantly, immersion of filter paper in the modified emulsion resulted in filter paper with markedly improved hydrophobic properties, while retaining surface pores and preserving filter capacity. This underscores the potential of lignin-modified emulsions for application in oil–water separation materials. Furthermore, this innovation led to a noteworthy 50% reduction in the usage of organofluorosilicone monomers, thereby mitigating potential hazards and environmental pollution associated with their use. Our utilization of sodium lignosulfonate as a modifier for organofluorosilicon styrene–acrylate emulsions represents a novel and promising approach for applications in oil–water separation and waterproof coatings. The integration of green and sustainable materials has significantly advanced environmentally friendly solutions, fostering more eco-conscious practices in industrial and commercial applications.

In this study, rosin polyethylene glycol ester was prepared by the reaction of natural rosin with PEG-400. It was modified with acrylic acid to prepare water-based ink binders. The results show that the reaction is carried out for 3 h at a molar ratio of rosin to PEG-400 of 1:4 and a catalyst and filler (Al₂O₃) of 30 wt%/RO. Products with high fixed content (83.4 wt%), low acid value (27.0 mg NaOH/g), high esterification rate (83.0%), good printability, and fast drying and flow rates are obtained. The key steps of the study include preparing polymers using natural rosin and PEG-400, esterification reaction, and modifying rosin polyethylene glycol ester emulsions. The focus of the study is to analyze the effect of the molar ratio of rosin to PEG-400, the type and content of the catalyst (filler), and the reaction time on the product to obtain the optimum process conditions. This study proposes a new method for the production of environmentally friendly water-based inks and provides valuable insights into future ink production and environmental technology.

Polymer coatings, when brought to elevated temperatures may experience thermal decomposition, leading to failure of their protective properties. The process of thermal decomposition can be followed by thermogravimetry (TG), which allows quantitative analysis. Applying the right theoretical model, the TG data can be extrapolated to a broader temperature range for evaluating the coating’s lifetime. The paper provides a thorough analysis of the current-state experimental and theoretical approaches in this area. As an example, thermal decomposition in nitrogen, air, and oxygen of dual polymer coatings on two different optical fibers is studied via isothermal and non-isothermal TG. For one of the coatings, the isothermal mass loss behavior resembles an n-th order kinetics function. For the other coating, the TG curves exhibit a more complex behavior, suggesting presence of an antioxidant in the chemical composition. From the non-isothermal TG data, using isoconversional Flynn–Wall–Ozawa, Kissinger–Akahira–Sunose and advanced Vyazovkin, Farjas–Roura and Budrugeac approaches, the activation energies are determined, and the isothermal mass loss functions are simulated. For several fiber/gas combinations, a significant discrepancy is observed between the experimentally obtained isothermal TG curves and those simulated from the non-isothermal data. The noted disagreement is analyzed in a view of miscellaneous assumptions of the advanced simulation methods, including the basic isoconversion principle. It is concluded that the isoconversional approaches are not applicable to the studied complex systems, and that the isothermal TG method should be used for determining the coating lifetime at elevated temperatures.