Tinted one-coat glass enamels for steel

A basic formula for one-coat glass enamel is developed, which makes it possible to obtain a wide color range of coatings for steel products with good surface quality. A number of ionic colorants is tested, mainly compounds of d-and f-elements. The properties of coatings are studied: chemical resistance, adhesion strength, luster, and heat resistance. Their firing temperature is determined. The obtained glass enamels can be used in industrial production. __________ Translated from Steklo i Keramika, No. 1, pp. 28–30, January, 2006.     

Transparent Surfactant/Epoxy Composite Coatings with Self‐Healing and Superhydrophilic Properties

In this paper, highly transparent, robust, and superhydrophilic polyethylene glycol tert‐octylphenyl ether nonionic surfactant/epoxy (Triton X‐100/epoxy, TXE) composite coatings are successfully prepared with a facile, one‐step drop‐casting method by mixing Triton X‐100 with an epoxy resin and an amine curing agent. The hydrogen bond reaction between the hydroxyl group of Triton X‐100 and the ether group of the epoxy resin improves the compatibility and reduces the glass transition temperature (T_g) of the TXE composite coatings. The free Triton X‐100 surfactant easily accumulates on the surface of the TXE composite coatings, which improves the hydrophilicity of the TXE composite coatings. The TXE composite coatings are self‐healable because of their low T_g and the migration of Triton X‐100 small molecule surfactant. Any damage arising from denting, cutting, or wiping by tetrahydrofuran can be healed, and the composite coating can regain its superhydrophilic properties through a heating process. The TXE composite coatings demonstrate excellent acid, alkali, salt, high temperature, and ultrasonic‐resistant properties. This facile preparation technique has the potential to be applied in the scalable fabrication of multifunctional coatings in anti‐fogging, oil–water separation, and optical–electric devices.     

Surface-Energy Determinations of Tin Oxide-Coated Soda–Lime–Silica Glass

The dispersive and polar surface-energy components, as well as the total surface energy, of tin oxide coatings on soda–lime–silica glass were determined by the Owens–Wendt method. The total surface energy of tin oxide is greater than soda–lime–silica glass and, more importantly, exhibits significantly more-dispersive and less-polar character. These results indicate that tin oxide is significantly more covalent than soda–lime–silica glass. It is postulated that the more-covalent tin oxide coatings increase the bond strength of organic coatings to soda–lime–silica glass. These effects improve the friction-damage resistance of glass surfaces coated with metal oxides and organics, compared with glass surfaces coated with organics only.     

Analysis of the dielectric spectra of composite sealing coatings in a wide frequency range

Polymer coatings on the basis of the biphenol-Novolac potting epoxy compound with a 65% content of spherical particles of fused quartz as a filler were studied by the method of dielectric spectroscopy in a wide frequency range. Dielectric measurements were performed in frequency and temperature ranges of (10⁻² to 5 × 10⁹) Hz and 20 to 200°C, respectively, on film samples of composite coatings formed on different substrates. It was shown that the application of dielectric spectroscopy allows one to study the effect of the degree of the adhesion interaction with the substrate on the processes of structuring in the epoxy polymer matrix and to investigate the degradation processes in the coatings under the effect of high temperature and relative humidity. It was also shown that the values of the glass transition temperature (T _g ) of the composite determined by applying the method of low-frequency dielectric spectroscopy agree well with the T _g values obtained by applying the method of dynamic mechanical analysis (DMA).     

Protective process coatings for hot plastic working of steels and alloys

A technology for dispersion doping of glass matrices for creating superplastic coatings, permitting isothermal deformation of alloys without the use of special equipment, has been developed. The protective glassy and glass-ceramic process coatings which have been developed possess a strong internal structure and high film-forming ability and they withstand substantial impact and tension loads with high strain (above 40%). __________ Translated from Steklo i Keramika, No. 6, pp. 24–27, June, 2007.     

酸处理及有机涂层对玻璃力学性能的影响

采用氢氟酸基溶液对玻璃进行腐蚀,研究酸腐蚀对玻璃强度的影响。对新鲜玻璃表面施加有机涂层,研究了玻璃表面的微观结构及力学性能。结果表明,酸腐蚀可以提高玻璃的强度,处理10 min后强度达到最大,但是强度稳定性差,表面易受损伤,在酸处理后的表面施加有机涂层可以极大提高玻璃的强度。其增强机制是,涂层填充了玻璃裂纹空隙,起到治愈损伤的效果,同时泊松抑制效应也对玻璃强度的增加起了作用。与物理钢化及化学钢化相比,这种综合增强方法明显提高了玻璃的力学性能,同时降低了成本。     

Zwitter-wettable acrylic polymeric coating on glasses for anti-fog applications

Anti-fog coatings have received significant attention because of their versatile applications to reduce light scattering during high humid conditions. Primarily, hydrophilic/superhydrophilic coatings are applied upon the transparent substrate to improve visibility at high humidity. The high solubility of the hydrophilic/superhydrophilic coatings in water is the main drawback for their long-term operational durability. We will report for the first time the development of functional copolymers which produces water insoluble hydrophilic coating upon application on glass surfaces. Such surfaces are commonly known as “Zwitter-Wettable” surfaces that have been developed from entirely polymeric substances using methacrylic and acrylic monomers. A series of random copolymers were synthesized using free radical polymerization of the common and commercially available monomers which were subsequently characterized using various analytical techniques, such as, GPC, ¹H-NMR, and FTIR. These newly designed copolymers contained both the hydrophobic parts made up of methyl and 2-ethylhexyl groups, which provide good stability under high humid conditions and hydroxyl and carboxylic acid groups which will provide the required hydrophilicity or water absorption capacity. These polymeric coatings on the glass surfaces exhibit water advancing contact angles in the range of 57 ± 3° to 78 ± 3° with excellent anti-fog property. The anti-fog property of the polymeric films could be tuned easily by changing the ratio of hydrophobic and hydrophilic monomers.     

Intentional Polymer Particle Contamination and the Simulation of Adhesion Failure due to Transit Scratches in Ultra-thin Solar Control Coatings on Glass

The major in-service failure mechanism of modern solar control coatings for the architectural glass can be mechanical (e.g., scratch damage). Many of these coatings are multilayer structures of less than 100 nm thickness and different coating architectures are possible (i.e., different layer materials, thickness and stacking order). For high-performance solar control coatings deposited by physical vapour deposition processes the active layer is a thin silver coating (approx. 8 nm thick) surrounded by antireflection coatings (e.g., ZnO, SnO₂) and barrier layers (e.g., TiO _x N _y ). Scratches are often found during delivery of the coated glass (called transit scratches) and it has been determined that the cause of the scratches was the polymer balls sprayed onto the glass to separate sheets while in transportation. This study has developed a simulation test for the transit scratches and has determined that the adhesion of layers within the multilayer stack is critical in determining performance. To test the adhesion of the coatings, coated samples have been subjected to scratch tests using a range of indenters and the most visible damage has been characterised. Through-thickness cracks were observed and it was seen that the coating was stripped by the balls at the weakest point in the coating stack. Microanalysis reveals this weakest point to be the silver/zinc oxide interface in the materials analysed in this study.     

Development of glass ceramic coatings containing hydroxyapatite

Glass ceramic composites — to be used for coatings on titanium implants — based on leucite glass with elevated flux content and added hydroxyapatite or a mixture of hydroxyapatite and fluorite are examined. It is established that pastes containing no more than 30% hydroxyapatite in leucite glass are the best materials for denture coatings. Pastes with a higher content of hydroxyapatite Ca₁₀(PO₄)₆(OH)₂(> 30%) are recommended for coatings on intramaxillary titanium implants. __________ Translated from Steklo i Keramika, No. 4, pp. 34–36, April, 2007.     

The effect of morphology on the corrosion inhibition and mechanical properties of hybrid polymer coatings

The durability and mechanical properties of epoxy ester coatings and films has been improved by blending with rigid aromatic polyurea (PU). The interaction of PU and epoxy ester was enhanced by coupling the polymers with polymethylhydrosiloxane. The reactions between various entities are analyzed by Fourier transform infrared spectroscopy and the change in physical and mechanical properties are studied by a dynamic mechanical analyzer. The corrosion resistance of the hybrid coatings was measured by direct current polarization method, direct current polarization (DCP). The addition of polymethylhydrosiloxane enhances the corrosion properties in the hybrid coatings. The surface morphology was analyzed by scanning electron microscopy. The glass transition temperature of the films increases with increasing PU concentration and a wide glass rubber transition range for hybrid coatings was achieved which confirms the higher impact strength of the hybrid coatings and films. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Sub-Tg annealing studies of UV-cured poly(urethane) acrylate coatings on optical fibers: A correlation of annealing behavior with microbending loss

Three types of UV-curable acrylate network systems were coated on optical fibers and studied calorimetrically. It was found that an endothermic transition of ΔH ～2-14 cal/g is superimposed on the glass transition of these coatings. This transition is present in the fiber coatings, but not in sheet form. The time-dependence of sub-T_g annealing of these crosslinked coatings (following rapid quenching from a temperature above the end temperature of the endotherm) was found to correlate with a mechanical-optical property of the coated fibers; namely, the contribution of the coating to the microbending loss of the optical fiber.     

Mechanical properties of sol–gel prepared nanocomposite coatings in the presence of titania and alumina-derived nanoparticles

Hybrid nanocomposite coatings were prepared by sol–gel method using silica, titania and alumina nanoparticles derived from their alkoxides precursors; in the presence of 3-glycidoxypropyl-trimethoxysilane (GPTMS) and bisphenol A (BPA) on 1050 aluminium alloy substrate. The effect of type and ratio of nanoparticles on mechanical behaviour of the coatings were investigated by dynamic mechanical thermal analysis (DMA) and nanoindentation experiments. DMA results demonstrated that the values of the glass transition temperature (T_g) and the temperature at maximum tan (δ), (T_t) as well as the storage modulus of the hybrid samples depend mainly on the silane content and titania to alumina molar ratio of nanoparticles in the coating composition. In addition, nanoindentaion experiments were performed to study the mechanical properties such as hardness, elastic modulus and E/H ratio for the nanocomposite hybrid coatings. Nanoindentation results indicate that the homogenous reinforced structure was formed in the surface of nanocomposite coating with incorporation of titania and alumina-derived nanoparticles. The incorporation of TiO₂ in comparison with AlOOH nanoparticles in the GPTMS-based coatings showed an improving effect on E/H ratio.     

Novel tailor-made diols for polyurethane coatings using a combination of controlled radical polymerization,ring opening polymerization,and click chemistry

Novel dihydroxy functional 3-arm star polymers were synthesized using a combination of atom transfer radical polymerization, ring opening polymerization, and click chemistry. The diols were characterized using gel permeation chromatography, Fourier transform infrared spectroscopy, and ¹H NMR spectroscopy. The diols were incorporated into polyurethane coatings, which were characterized using differential scanning calorimetry, thermogravimetric analysis, pendulum hardness, water contact angle, and methyl ethyl ketone double rubs. The coatings showed an increase in the water contact angle values as the percentage of the polystyrene-based diol was increased. Similarly, the coatings with the poly(tert-butyl acrylate)-based diols showed a decrease in the glass transition temperature values with an increase in the diol content. It is expected that the use of controlled radical polymerization would allow for the synthesis of novel tailor-made functional polymers to achieve tunable coatings properties.     

Correlation between microstructure and properties of biocomposite coatings

A SiO₂–CaO–Na₂O (SCN) based bioactive glass was used to prepare glass–matrix/Ti particle composite coatings (SCNT). The coatings were obtained by vacuum plasma spray (VPS) on Ti–6Al–4V substrates. Two different deposition methods have been compared: (a) VPS of powders obtained by ball milling of sintered composites; (b) in situ plasma spray of mixed titanium and glass powders. For comparative purposes, pure SCN glass coatings were produced. The coating morphology and microstructure were observed by optical and scanning electron microscopy, compositional analyses by energy dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). Comparative mechanical tests were carried out by shear tests and by Vickers indentations at the interface between the substrate and the coatings. The bioactivity of glass- and composite coatings was investigated in vitro by soaking them in a simulated body fluid (SBF) with the same ion concentration of the human plasma. All the layers retain their starting composition. The composite coatings obtained by VPS of the powdered presintered composites showed a better mechanical behaviour with respect both to the composite coatings obtained by the in situ method and to the pure glass coatings. Both the glass- and the two kind of composite coatings revealed to be bioactive by the growth of a thick apatite layer after 30 days of soaking in SBF. The electrochemical behaviour of the SCNT coatings was evaluated by means of potentiodynamic anodic polarization curves and free corrosion potential measurements in Ringer solution at 25 °C. For comparative purposes the same analyses were performed on analogous bioactive glass-matrix/Ti particle composite coated samples, based on the system TiO₂–SiO₂–CaO–B₂O₃ (TSCB), and obtained both by the in situ and by presintering method as well. The results of the electrochemical tests showed a better corrosion behaviour of the samples coated by VPS of powdered sintered composites with respect to those coated by in situ VPS composites.     

Guidelines for dryer design based on results from non‐Fickian model

In polymer solution coatings below the glass transition temperature of the pure polymer, the coating can go undergo a glass transition and develop stresses during drying. When stresses develop, a non‐Fickian model accurately describes solvent mass transport in drying polymer coatings. The non‐Fickian model includes the solvent transport due to both stress and concentration gradients. This article presents a non‐Fickian model, which predicts a lower residual solvent than does the corresponding Fickian model. We showed in an earlier article that the non‐Fickian model predicts trapping skinning (higher residual solvent under more intense operating conditions) at higher drying gas‐flow rates. In this article, the non‐Fickian model was used to investigate how the gas‐flow rate, dry film thickness, and substrate thickness affect the residual solvent for a single‐zone dryer. This work recommends guidelines for choosing gas‐flow rates, gas temperatures, and substrate thickness to minimize the residual solvent. The model predictions show that, at any gas temperature, the residual solvent is minimum at an intermediate gas‐flow rate. The trapping skinning effect is less evident in thicker coatings and substrates. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 477–486, 2003     

A Simple Strategy to Achieve Mussel‐Inspired Highly Effective Antibacterial Coating

Although significant progress has been made in the preparation of mussel‐inspired antibacterial coatings, continual challenges still remain in pursuing more facile and simpler fabrication methods to construct more robust and effective coatings. In this study, quaternized catechol (QCat), which is synthesized via a simple quaternization reaction from two commercially available materials, 2‐chloro‐3′,4′‐dihydroxyacetophenone and N,N‐dimethyldodecylamine, is used as a reactive antimicrobial agent to fabricate mussel‐inspired antibacterial coatings. Specifically, QCat reacts with branched polyethyleneimine (PEI) in Tris‐HCl solution through a cross‐linking reaction between amino and catechol groups to form a homogeneous coating on various substrates via a simple co‐deposition process. The formed PEI/QCat coating exhibits highly effective antimicrobial activity against both Staphylococcus aureus and Escherichia coli and good adhesion on glass, metal, and plastic substrates. Such a simple fabrication process makes it a potential candidate for industrial and medical applications.     

Decorated glass based on slime wastes from organic plants

The possibility of using slime wastes from organic plants for fabrication of decorated glass during synthesis of metal oxide coatings on its surface was investigated. The expediency of using wastes as raw material for film-forming solutions was demonstrated, and the properties of the coatings were reported.Translated from Steklo i Keramika, Nos. 3–4, pp. 2–5, March–April, 1994.     

Preparation of scratch resistant superhydrophobic hybrid coatings by sol–gel process

Organic–inorganic hybrid coatings on glass substrates with superhydrophobic properties and with improved scratch resistance were obtained by means of applying a multilayer approach including multiple sol–gel processes. The coatings exhibited a water contact angle (WCA) higher than 150°. Ultraviolet (UV)-curable vinyl ester resins and vinyltriethoxysilane (VTEOS) as coupling agent were employed to increase the adhesion between substrate and the inorganic layers. The surfaces were characterized by means of dynamic contact angle and roughness measurements. Indeed, the occurrence of superhydrophobic behavior was observed. The scratch resistance of the hybrid coatings was tested to evaluate the adhesion of the coatings to the glass substrate. The proposed preparation method for scratch resistant, mechanically stable, superhydrophobic coatings is simple and can be applied on large areas of different kinds of substrates.     

Combinatorial approach to study the effect of acrylic polyol composition on the properties of crosslinked siloxane-polyurethane fouling-release coatings

The effect of acrylic polyol composition on the properties of crosslinked siloxane-polyurethane coatings was explored. An acrylic polyol library was synthesized using batch solution polymerization and characterized using high-throughput gel permeation chromatography (Rapid-GPC) and differential scanning calorimetry (DSC). Siloxane-polyurethane coatings were prepared from 3-aminopropyl-terminated poly(dimethylsiloxane) (PDMS), the acrylic polyols and a polyisocyanate crosslinker. The siloxane-acrylic-polyurethane coatings were tested for mechanical and physical properties. The siloxane-polyurethane coatings had a systematic variation in glass transition temperature and had water contact angles ranging from 95° to 100°. Many of the coatings also showed a low-force of release in the pseudo-barnacle pull-off adhesion test. Performance testing of the fouling-release properties of the siloxane-polyurethane coatings on array panels with algae, namely the diatom Navicula and sporelings (young plants) of the green seaweed Ulva was also conducted. Presented at the 2006 FutureCoat! conference, sponsored by the Federation of Societies for Coatings Technology, in New Orleans, LA, on November 1–3, 2006.     

Fabrication of transparent super-hydrophilic coatings with self-cleaning and anti-fogging properties by using dendritic nano-silica

In this paper, super-hydrophilic coatings were generated on glass substrates via dipping method using colloidal silica with different morphologies as the main raw materials. The coatings were characterized by transmission electron microscope (TEM), field emission scanning electron microscope (FE-SEM), water contact angle (WCA) analyzer, and atomic force microscope (AFM). The hardness, adhesion, self-cleaning and antifogging properties of the coatings were examined. It has been found that the hydrophilicity of the coating can be significantly improved by using dendritic silica nanoparticles, and the comprehensive performance of the coating is optimum when the branch length of dendritic silica nanoparticles is about 60 nm. The coatings show super-hydrophilicity (CA, 1.7°), and high transmittance (the maximum light transmittance of the coating on glass is increased by 2.2%). Moreover, the coating is very effective in eliminating fog and dirt. The hardness and the adhesion of the coating can be reached 9H and grade 0, respectively, indicating that the coatings have a good mechanical performance, which is essential for its application.