The Experts below are selected from a list of 9963 Experts worldwide ranked by ideXlab platform
Nigel P. Brandon - One of the best experts on this subject based on the ideXlab platform.
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Screen-Printing Inks for the fabrication of solid oxide fuel cell films: A review
Renewable & Sustainable Energy Reviews, 2017Co-Authors: Mahendra Rao Somalu, Wan Ramli Wan Daud, Andanastuti Muchtar, Nigel P. BrandonAbstract:Fabrication of solid oxide fuel cell (SOFC) components via a simple and economical technique is critical to lower the overall manufacturing cost of SOFCs. Thus, screen-Printing is widely used to fabricate SOFC components having thickness in the range of 10–100µm. Fabrication of optimized screen-Printing Inks is highly significant for the production of high quality films with improved performance. The effect of solid, binder, solvent and dispersant on the ink rheological properties and performance of resultant films must be deeply understood for the fabrication of optimized screen-Printing Inks. These effects can be optimized by measuring the rheological properties of Inks such as viscosity, yield stress, thixotropy and viscoelasticity for application at a specific printer setting. Understanding the relationship between the composition and rheology of the Inks may enhance the properties and performance of the resultant screen-printed films. Furthermore, these parameters can be correlated to the film properties such as mechanical strength, electrical conductivity and electrochemical properties of the resultant films. The focus of this review paper is to understand the underpinning science of ink rheology and processing conditions of screen-Printing Inks for the fabrication of high performance SOFC electrodes and/or electrolyte.
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rheological studies of nickel scandia stabilized zirconia screen Printing Inks for solid oxide fuel cell anode fabrication
Journal of the American Ceramic Society, 2012Co-Authors: Mahendra Rao Somalu, Nigel P. BrandonAbstract:Screen Printing is widely used to fabricate thick film solid oxide fuel cell (SOFC) electrodes, followed by drying and high temperature sintering. This study focuses on the rheology of such screen Printing Inks for the fabrication of porous composite anodes of nickel and scandia- stabilized zirconia. Inks with 1–3 wt% binder were suitable for screen Printing, but Inks with higher binder content were tacky and difficult to print. The particle network strength, important to the production of films with good particle connectivity and mechanical strength, increased as the binder content increased. Inks having 3 wt% binder showed the best balance of thixotropic and viscoelastic properties, resulting in printable films with minimum numbers of film defects and are therefore recommended from this study, with the texanol ink appearing to be better than terpineol due its minimum number of film defects.
Mahendra Rao Somalu - One of the best experts on this subject based on the ideXlab platform.
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Screen-Printing Inks for the fabrication of solid oxide fuel cell films: A review
Renewable & Sustainable Energy Reviews, 2017Co-Authors: Mahendra Rao Somalu, Wan Ramli Wan Daud, Andanastuti Muchtar, Nigel P. BrandonAbstract:Fabrication of solid oxide fuel cell (SOFC) components via a simple and economical technique is critical to lower the overall manufacturing cost of SOFCs. Thus, screen-Printing is widely used to fabricate SOFC components having thickness in the range of 10–100µm. Fabrication of optimized screen-Printing Inks is highly significant for the production of high quality films with improved performance. The effect of solid, binder, solvent and dispersant on the ink rheological properties and performance of resultant films must be deeply understood for the fabrication of optimized screen-Printing Inks. These effects can be optimized by measuring the rheological properties of Inks such as viscosity, yield stress, thixotropy and viscoelasticity for application at a specific printer setting. Understanding the relationship between the composition and rheology of the Inks may enhance the properties and performance of the resultant screen-printed films. Furthermore, these parameters can be correlated to the film properties such as mechanical strength, electrical conductivity and electrochemical properties of the resultant films. The focus of this review paper is to understand the underpinning science of ink rheology and processing conditions of screen-Printing Inks for the fabrication of high performance SOFC electrodes and/or electrolyte.
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rheological studies of nickel scandia stabilized zirconia screen Printing Inks for solid oxide fuel cell anode fabrication
Journal of the American Ceramic Society, 2012Co-Authors: Mahendra Rao Somalu, Nigel P. BrandonAbstract:Screen Printing is widely used to fabricate thick film solid oxide fuel cell (SOFC) electrodes, followed by drying and high temperature sintering. This study focuses on the rheology of such screen Printing Inks for the fabrication of porous composite anodes of nickel and scandia- stabilized zirconia. Inks with 1–3 wt% binder were suitable for screen Printing, but Inks with higher binder content were tacky and difficult to print. The particle network strength, important to the production of films with good particle connectivity and mechanical strength, increased as the binder content increased. Inks having 3 wt% binder showed the best balance of thixotropic and viscoelastic properties, resulting in printable films with minimum numbers of film defects and are therefore recommended from this study, with the texanol ink appearing to be better than terpineol due its minimum number of film defects.
Mariusz Tryznowski - One of the best experts on this subject based on the ideXlab platform.
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The wettability effect of branched polyglycerols used as performance additives for water-based Printing Inks
Journal of Coatings Technology and Research, 2018Co-Authors: Mariusz Tryznowski, Zuzanna Żołek-tryznowska, Joanna Izdebska-podsiadłyAbstract:The aim of this work was to study the influence of primary and secondary hydroxyl groups in the branched polyglycerol on the selected properties of water-based Printing ink and copies printed with water-based flexographic Printing Inks. The branched polyglycerols were synthesized through anionic ring-opening polymerization using trimethylolpropane as a starting material. Obtained polyglycerol exhibited an irregular structure containing primary and secondary or predominantly primary hydroxyl groups in the macromolecule. The analysis (FTIR, ^1H NMR, ^13C NMR) confirmed the structure of polyglycerols. Obtained polyglycerols were then used as a performance additive in a water-based flexographic Printing ink. The contact angles of the Printing Inks on the Printing base were measured. The impact of a small amount of branched polyglycerol on the Printing ink color was examined by studying the optical density of a full-tone area, the color values (CIELAB), the total color difference $$\Delta E_{ab}^{*}$$ Δ E ab ∗ , and gloss of the dried ink film. In general, the addition of branched polyglycerol containing only primary hydroxyl groups improved the wettability of the plastic film and gloss of Printing ink with an acceptable total color difference $$\Delta E_{ab}^{*}$$ Δ E ab ∗ in contrast to branched polyglycerol with primary and secondary hydroxyl groups.
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improvement of light fastness of water based Printing Inks with addition of glycerol derivative containing thiol groups
Coloration Technology, 2018Co-Authors: Joanna Izdebskapodsiadly, Zuzanna żolektryznowska, Tatiana Annusik, Mariusz TryznowskiAbstract:The aim of this work was to study the influence of a glycerol derivative with thiol groups, 3,6-dithia-1,8-octanediol (DTO), on light fastness of prints overprinted with water-based flexographic Printing Inks. Laboratory Printing was performed on various plastic films (BOPP and PE). The effect of a small amount of DTO on Printing ink colour was examined by studying the optical density of a full tone area, relative Printing contrast and the colour values (CIELAB), and the total colour difference, ΔEab∗. Artificial ageing was applied in order to investigate DTO influence on colourfastness of CMY Printing Inks. Densitometry and spectrophotometric parameters were measured during artificial ageing by irradiation. Additionally, FTIR spectroscopy was used to observe the changes in ink film on Printing bases before and after ageing. The print quality of investigated prints is widely discussed. In general, DTO addition influenced the printability of the plastic film and the optical density of a full tone area with an acceptable total colour difference ΔEab∗. Furthermore, Printing Inks with added DTO exhibited higher optical density and smaller changes of ΔEab∗ during artificial ageing. Moreover, the FTIR spectra of Printing ink films with added DTO after ageing did not exhibit any perceptible changes in contrast with the original Printing ink.
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the wettability effect of branched polyglycerols used as performance additives for water based Printing Inks
Journal of Coatings Technology and Research, 2018Co-Authors: Mariusz Tryznowski, Zuzanna żolektryznowska, Joanna IzdebskapodsiadlyAbstract:The aim of this work was to study the influence of primary and secondary hydroxyl groups in the branched polyglycerol on the selected properties of water-based Printing ink and copies printed with water-based flexographic Printing Inks. The branched polyglycerols were synthesized through anionic ring-opening polymerization using trimethylolpropane as a starting material. Obtained polyglycerol exhibited an irregular structure containing primary and secondary or predominantly primary hydroxyl groups in the macromolecule. The analysis (FTIR, 1H NMR, 13C NMR) confirmed the structure of polyglycerols. Obtained polyglycerols were then used as a performance additive in a water-based flexographic Printing ink. The contact angles of the Printing Inks on the Printing base were measured. The impact of a small amount of branched polyglycerol on the Printing ink color was examined by studying the optical density of a full-tone area, the color values (CIELAB), the total color difference \(\Delta E_{ab}^{*}\), and gloss of the dried ink film. In general, the addition of branched polyglycerol containing only primary hydroxyl groups improved the wettability of the plastic film and gloss of Printing ink with an acceptable total color difference \(\Delta E_{ab}^{*}\) in contrast to branched polyglycerol with primary and secondary hydroxyl groups.
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Improvement of light fastness of water‐based Printing Inks with addition of glycerol derivative containing thiol groups
Coloration Technology, 2017Co-Authors: Joanna Izdebska-podsiadły, Tatiana Annusik, Zuzanna Żołek-tryznowska, Mariusz TryznowskiAbstract:The aim of this work was to study the influence of a glycerol derivative with thiol groups, 3,6-dithia-1,8-octanediol (DTO), on light fastness of prints overprinted with water-based flexographic Printing Inks. Laboratory Printing was performed on various plastic films (BOPP and PE). The effect of a small amount of DTO on Printing ink colour was examined by studying the optical density of a full tone area, relative Printing contrast and the colour values (CIELAB), and the total colour difference, ΔEab∗. Artificial ageing was applied in order to investigate DTO influence on colourfastness of CMY Printing Inks. Densitometry and spectrophotometric parameters were measured during artificial ageing by irradiation. Additionally, FTIR spectroscopy was used to observe the changes in ink film on Printing bases before and after ageing. The print quality of investigated prints is widely discussed. In general, DTO addition influenced the printability of the plastic film and the optical density of a full tone area with an acceptable total colour difference ΔEab∗. Furthermore, Printing Inks with added DTO exhibited higher optical density and smaller changes of ΔEab∗ during artificial ageing. Moreover, the FTIR spectra of Printing ink films with added DTO after ageing did not exhibit any perceptible changes in contrast with the original Printing ink.
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branched polyglycerols as performance additives for water based flexographic Printing Inks
Progress in Organic Coatings, 2015Co-Authors: Zuzanna żolektryznowska, Joanna Izdebska, Mariusz TryznowskiAbstract:Abstract The aim of this work was to study the influence of polyglycerols on the selected properties of water-based Printing ink and prints overprinted with water-based flexographic Printing Inks. Modified flexographic Inks were laboratory printed on polyethylene plastic film. The impact of small amounts of various commercially available polyglycerols on Printing ink colour was examined for the optical density of the full-tone area, colour values (CIELAB) and total colour difference Δ E a b * and the gloss of the dried ink film. The dry and wet rub resistance of overprinted samples was investigated. In general, the addition of polyglycerols improved the wet and rub resistance of water-based flexographic Printing ink with an acceptable total colour difference Δ E a b * . The optical density and the gloss increased for those Printing Inks containing polyglycerols as compared to original Printing ink. The small addition of glycerol ethoxylate to the water-based Printing ink improved the wettability of the plastic film and the wet and dry rub resistance.
Marta Klanjšek Gunde - One of the best experts on this subject based on the ideXlab platform.
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Colorimetric description of thermochromic Printing Inks
Acta Graphica, 2017Co-Authors: Maja Jakovljević, Mojca Friškovec, Rahela Kulčar, Dario Tomašegović, Marta Klanjšek GundeAbstract:The dynamic colour of three commercial reversible thermochromic Inks were studied. Thermochromic Printing Inks change their colour according to a change in temperature. The two types of thermochromic Inks are based on leuco dyes and liquid crystals. The thermochromic effect achieved by liquid crystals is quite different from the effect achieved with leuco dyes. Leuco dyes change from a coloured to a colourless state, or from one colour shade to another due to structural changes inside leuco dye molecules under assistance of developer. Liquid crystal Inks change colour continuously throughout the spectrum, producing iridescent colours starting from red and shifting to blue part of the spectrum with temperature. The colour change results from the way light interacts with special arrangement of liquid crystal molecules to produce coloured reflection by interference, and with the variation of this structure with temperature. In this paper we will present differences between two types of thermochromic Printing Inks giving careful colorimetric characterization.
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Thermochromic Printing Inks for smart packaging applications
2014Co-Authors: Maja Jakovljević, Rahela Kulčar, Suzana Pasanec Preprotić, Ante Poljičak, Sonja Jamnicki, Marta Klanjšek GundeAbstract:Thermochromic Printing Inks (TC Inks) are the type of chromogenic or colour chang-ing Inks that change colour under certain circumstances. The colour change in TC Inks is caused by the exposure to temperature gradient. TC Printing Inks are one of the candidates for active and smart packaging of the future. TC Inks can be used not only for security Printing and brand protection, but also for marketing and novelty Printing. Furthermore TC Inks have great potential to be used as temperature indica-tors and heat sensitive pharmaceuticals. TC Inks can be based on leuco dyes or liq-uid crystals. Leuco dye - based Inks are more common, with several know applica-tions. On the other hand, liquid crystal - based Inks are rather uncommon. The rea-son why liquid crystals are used less frequently than leuco dyes lies in the fact that they are both, more difficult to work with and more expensive than leuco dyes. How-ever, liquid crystals are more sensitive to temperature change than leuco dyes, meaning that they can be used in delicate experiments where small change in tem-perature has to be noted. Leuco dyes are in greater use than liquid crystals in a vari-ety of different products that require less accurate temperature readings. Communication mechanism of these Inks is based on temperature dependence of the colour, occurring inside the working temperature range. They are available as water – based, solvent – based or without solvent as UV curable products, and can be produced for screen, flexo or offset Printing. The possible applications of both leuco dye - and liquid crystal - based TC Printing Inks will be thoroughly discussed through our research, which will be presented through two separate case studies. Each study will show the potential of TC Printing Inks for use in active and smart packaging based on specific examples. Possible limitations as well as benefits of those Inks will also be presented.
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Light fastness and high‐temperature stability of thermochromic Printing Inks
Coloration Technology, 2013Co-Authors: Mojca Friškovec, Rahela Kulčar, Marta Klanjšek GundeAbstract:Thermochromic Printing Inks are known for their low stability under the influence of various external conditions, but the consequences of the phenomenon on dynamic colorimetric properties have not yet been analysed. In this work, thermochromic prints were exposed to light and heated at two different temperatures, 150 and 200 °C, for varying time periods. The changes to the dynamic colour properties of the samples were described. It was found that both exposure to light and heating to high temperatures degrade the dynamic properties of thermochromic Inks ; however, they have different effects on the colour hysteresis. The corresponding loops contract with light exposure and heating, which is best described by the area of the entire colour loop. Exposure to light broadens the corresponding loop, while heating makes it narrower. The chemical stability of Inks after exposure was also analysed by forced oxidation applying a weakly ionized oxygen plasma. Stability of thermochromic samples is a combined effect of the binder, the polymeric shell and the active core inside the pigment capsules. Our results show that poor stability against light and high temperatures has different origins.
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optical properties of thermochromic liquid crystal Printing Inks
Printing Future Days, 2013Co-Authors: Maja Jakovljević, Mojca Friškovec, Marta Klanjšek Gunde, Branka LozoAbstract:Thermochromic liquid crystal Inks (TLCs) reflect incident light in a rather narrow spectral region. This phenomenon is caused by selective reflection of light on chiral (twisted) molecular structure which changes its distribution with temperature. The reflected light produces iridescent colour which is continuously shifted from red to blue part of the spectrum with temperature, the effect which is known as „colour play“. This research is focused on the optical properties of a water-based TLC ink. The ink was screen-printed over black and white matte uncoated paper. The temperature dependent iridescent colours are seen very clearly when the ink is printed over black background, while on the white substrate is hardly visible. The observed effects were quantified by spectral reflectances applying (45°:0°) and (8°:di) geometries in the 400-700 and 200-1500 nm spectral regions, respectively. The measured temperature dependent iridescent colours were analyzed.
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Functional properties of the leucodye-based thermochromic Printing Inks
2011Co-Authors: Marta Klanjšek Gunde, Ondrej Panák, Nina Hauptman, Marie Kaplanová, Mojca Friškovec, Rahela Kulčar, Alenka VeselAbstract:Leuco dye-based thermochromic Printing Inks are one of the candidates for active packaging of the future. Such an advanced application requires much more knowledge about these novel Inks as it is currently provided by the manufacturers. Thermochromic Inks reversibly change from colored to discolored state in a certain temperature region. Details of this change and the width of the temperature region required for it are characteristic properties of a selected ink. Inside this region the color of a sample depends on temperature and thermal history ; this is a color hysteresis, which contains a sort of memory. The activation temperature, which is the only parameter given by the producer to describe the change of color, does not reveal any characteristic properties of this temperature dependent color loop. Therefore other parameters were introduced to characterize the analyzed thermochromic Inks. Thermochromic material is leuco dye-based composite which is protected in round-shaped capsules. They are much larger than pigments in conventional Inks. Their large size can seriously influence the appearance of very thin layers, being the size of capsules. The polymer envelopes of pigment capsules are more stable against oxidation than the binder. If these envelopes are damaged, the dynamic color is irreversibly lost. The lightfastness of thermochromic samples is low. Thicker layers retain their dynamic color up to longer light exposures. Light changes color of the fully colored and totally discolored states and of all intermediate states ; the changes are larger in the colored state and smaller in the discolored one.
Bohuslava Havlínová - One of the best experts on this subject based on the ideXlab platform.
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Water-reducible flexographic Printing Inks—rheological behaviour and interaction with paper substrates
Journal of Materials Science, 1999Co-Authors: Bohuslava Havlínová, V. Cicák, Vlasta Brezová, L'. HorňákováAbstract:The rheological behaviour of 5 water-reducible flexographic Printing Inks was tested using viscometer with the cone and plate geometry. The obtained shear stress versus shear rate curves for the original Inks, and additionally, for the mixtures with various amount of added water, exhibit pseudoplastic behaviour, and were successfully fitted by Ostwald and Casson models. The viscosity of Printing Inks after addition of water was tested also by means of outflow funnel. The transfer of flexographic Inks on the different paper substrates was examined by optical density measurements. The density curves confirmed that the ink concentration above 50 wt% is sufficient to obtain the constant value of optical density. The best ink transfer to the investigated paper substrates was observed for folding carton characterized by the high value of smoothness.
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water reducible flexographic Printing Inks rheological behaviour and interaction with paper substrates
Journal of Materials Science, 1999Co-Authors: Bohuslava Havlínová, V. Cicák, Vlasta Brezová, L HorňakovaAbstract:The rheological behaviour of 5 water-reducible flexographic Printing Inks was tested using viscometer with the cone and plate geometry. The obtained shear stress versus shear rate curves for the original Inks, and additionally, for the mixtures with various amount of added water, exhibit pseudoplastic behaviour, and were successfully fitted by Ostwald and Casson models. The viscosity of Printing Inks after addition of water was tested also by means of outflow funnel. The transfer of flexographic Inks on the different paper substrates was examined by optical density measurements. The density curves confirmed that the ink concentration above 50 wt% is sufficient to obtain the constant value of optical density. The best ink transfer to the investigated paper substrates was observed for folding carton characterized by the high value of smoothness.
