Preparation Of Pigments Research Articles

Chemistry Inspired by the Colors of Fruits, Flowers and Wine.

An overview is provided of the status of research at the frontiers of investigation of the chemistry and photochemistry of two classes of natural plant pigments, the anthocyanins and the betalains, as well as of the pyranoanthocyanin pigments formed from anthocyanins during the maturation of red wine. Together, anthocyanins and betalains are responsible for almost all of the red, purple and blue colors of fruits and flowers and anthocyanins and pyranoanthocyanins are major contributors to the color of red wines. All three types of pigments are cationic below about pH 3, highly colored, non-toxic, reasonably soluble in water or alcohol and fairly stable to light. They exhibit good antioxidant or antiradical activity and, as part of our diet, confer a number of important health benefits. Systematic studies of model compounds containing the basic chromophoric groups of these three types of pigments are providing a deeper understanding of the often complex chemistry and photochemistry of these pigments and their relationship to the roles in vivo of these pigments in plants. These natural pigments are currently being exploited as starting materials for the preparation of novel semi-synthetic dyes, pigments and fluorescence probes.

Preparation and surface modification of transparent yellow iron oxide pigment

Nowadays the transparent yellow iron oxide pigment is widely applied in many industries. In recent years, China has been a large producer of iron oxide pigments with over 50% of its total annual output being exported. So it is of necessity to have a comprehensive understanding of the domestic iron oxide pigments production and its development status. According to the characteristics and application of transparent yellow iron oxide pigment. This paper studies several preparation and surface modification methods of the pigment. By adding various additives during and after the reaction, a transparent iron yellow colour can be obtained with excellent transparency, good dispersibility, pure hue and excellent heat resistance.

Characterization of copper-based pigment preparation and alteration products

ABSTRACTCopper-based pigments are common in works of art that show signs of decay on green and blue areas and are frequently associated with the degradation of organic substrates and/or media (drying oils, cellulose, etc.). The exact causes of degradation remain unknown. This prompted us to study possible starting and degradation products of one especially reactive copper pigment, verdigris (copper acetate), as well as pigments of the same family (salt and soap greens). Preparation of pigments using historical methods was followed by spectroscopic and crystallographic characterization using Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Synthesis of verdigris and verdigris-like pigments resulted in a mixture of starting polymorphs of verdigris, including neutral and basic verdigris. With accelerated aging, pigments degraded to a polymorph of basic verdigris when not affected by organic media, whereas pigments on cellulosic substrates showed oxidized copper species. With this study, we are beginning to understand verdigris starting materials and highlight the complex interactions between pigments and substrates that influence pigment degradation pathways.

Preparation of Magnetic Pearlescent Pigment Mica/Fe3O4 by Thermally Decomposing Ferric Formate Composite Containing Hydrazine

Mica/Fe3O4 pearlescent pigment was synthesized via thermal decomposition of ferric formate composite containing hydrazine (composite salts), which was deposited on the surface of mica. The obtained product showed good dispersity, magnetic property and special black luster. The effects of pH value, sodium hydroxide concentration, molar ratio, stirring speed and temperature on composited salt coating rate and smooth on the mica surface were investigated. The optimum parameters were obtained including the pH value, the concentration of sodium hydroxide, the molar ratio of formic acid to Fe3+, the velocity of magnetic stirring, calcination temperature and time. It was also found that coating properties such as smoothness, compactness and color deepness were influenced by different pH, temperatures, sodium hydroxide concentration and so on. The products were characterized by X-ray diffraction, high resolution scan electron microscopy, vibrating sample magnetometer, color measurement and element analysis. The results indicates that a concentration 1.0 mol/L, a pH value between 4.0 and 4.5, a formic acid/Fe3+ ratio = 3, a stirring speed at 180 rpm/min at room temperature are the best conditions to obtain a good coating performance and a suitable pearly luster effect. Pearlescent pigment was prepared by the decomposition of composite salt on micron surface. Different parameter were evaluated separately to obtain suitable products having a significant pearly luster effect. The best results were observed when sodium hydroxide concentration is 1.0 mol/L, the value of pH is between 4.0 and 4.5, the molar ratio [formic acid]/[Fe3+] is 3:1 and the stirring speed is 180 rpm/min and the products is prepared under room temperature.

Enzymatic preparation and antioxidant activity of the phloridzin oxidation product

During apple processing, phloridzin, the main flavonoid in apples, can be oxidized to the yellow pigment, which contributes to the color of apple juice and ciders. However, there was no report about the bioactivities of this yellow pigment. In this study, the oxidation of phloridzin catalyzed by tyrosinase from mushroom was investigated. The main oxidation product with bright yellow color was purified and identified as the phloridzin oxidation product j (POPj) based on electrospray ionization mass spectrometry (ESI-MS) and 13C nuclear magnetic resonance (13C-NMR) spectroscopy. In the chemical and cellular system, POPj exhibited the higher peroxyl radical-scavenging activity than phloridzin. Our results suggested that POPj was a kind of potential food yellow pigment with antioxidant activity, which partly explained health-promoting functions of apple juices and ciders. Practical applications In view of the potential toxicity of the artificial food yellow pigment, the need for natural and safe yellow pigment is increasing. In this study, the enzymatic preparation of the yellow pigment derived from phloridzin was investigated. Its antioxidant activity was first reported. This study can prompt the application of this new yellow pigment in food industry.

Mullite–Cobalt (II, III) Oxide System: Preparation of Ceramic Pigment Using Recycling of Fly Ash

The present work depends on recycling of fly ash by preparation of stoichiometric mullite containing various amounts of Co3O4; 0, 5, 10, 15 wt.% to obtain pigment ceramic materials. The mixtures were sintered at different temperatures; 1250, 1350, 1400, 1450, 1500 and 1550 ∘C to follow the phase compositions, structure, physical, mechanical, electrical, magnetic properties and the color behaviors. The results indicate that the sintering at 1250 ∘C is the optimum condition for the formation of the blue pigment ceramic materials. The sintering from 1250 to 1500 ∘C shows increase in the bulk density and the strength properties up to 15 wt.% Co3O4. The incorporation of cobalt (II, III) oxide into the mullite system enhances the electrical and magnetic properties to be used as ferromagnetic materials.

Preparation of ground calcium carbonate-based TiO2 pigment by a two-step coating method

A two-step coating method for preparing ground calcium carbonate-based TiO2 pigment (GCTD) was proposed and studied in this paper. The tetraethoxysilane (TEOS, C8H20O4Si) was selected as Si source. Aqueous ammonia was used as precipitant in the first coating step while titanyl sulfate (TiOSO4·2H2O) was used as Ti source in the second step. The Energy dispersive spectrometer (EDS) and X-ray fluorescence (XRF) results prove that SiO2 is coated on the surface of ground calcium carbonate (GCC) particles successfully. The X-ray diffraction (XRD) and transmission electron microscopy (TEM) results demonstrate that the coated SiO2 is in the form of amorphous. The EDS, XRD, TEM and Scanning electron microscope (SEM) results show that TiO2 is coated on the surface of SiO2 coated GCC (SiO2@GCC) and TiO2 particles are composed of mixed crystal of anatase and rutile. The hiding power of obtained GCTD is significantly improved compared with ordinary composite TiO2 pigment (CTD) and close to that of anatase TiO2 (ATD). The whiteness and lightness of this GCTD are just slightly decreased compared to that of CTD and ATD. Nevertheless, its oil absorption value is some higher than that of ATD but lower than that of CTD.

Development and preparation of oxide mixture-based pigments for anticorrosion paints

PurposeThe aim of the work is to develop an anticorrosion pigment based on an oxide mixture with lamellar particles. The pigments are prepared from lamellar zinc, zinc oxide and magnetite by calcination. An alkaline earth carbonate is added when embedding a third cation in the lattice of the ferrite that forms the envelope of the lamellar zinc. The properties of the pigments are tested both in the powdered state and when embedded in an epoxy-ester system using different pigment volume concentrations (PVC).Design/methodology/approachThe properties of paints containing synthesised oxide mixture-based pigments at various volume concentrations and with the Q factor – Q = PVC/CPVC = 0.65 – were examined (where CPVC is critical pigment volume concentration). A series of isometric ferrite pigments were also synthesised for a comparison. Paints of both types with PVC = 10, 15 and 20 per cent were formulated. Steel panels coated with the paints were subjected to corrosion and mechanical tests.FindingsThe oxide mixtures with lamellar particles were subjected to particle size analysis and found to make up a broad distribution curve. Electron microscopy photographs confirmed that the oxide mixture pigments contained lamellar particles with a surface layer. A high anticorrosion effect was achieved owing to the combination of different oxide types.Research limitations/implicationsThe properties of the oxide mixtures with lamellar particles are described. Their particle distribution curves can be obtained by particle size analysis methods with a view to obtaining additional information on the status and properties of the pigment particles that may be useful in the development of better paints/coating materials.Practical implicationsOxide mixtures with lamellar particles can be used in paints protecting construction steel.Originality/valueThe composition of the prepared oxide mixture-based pigments is novel. Each oxide acts by its own anticorrosion mechanism and the final beneficial effect is due to their concerted action.

Preparation of TiO2-coated barite composite pigments by the hydrophobic aggregation method and their structure and properties

We obtained hydrophobic barite (BaSO4) and rutile titanium dioxide (TiO2) particles (as raw materials) by organic surface modification. Subsequently, TiO2-coated barite composite pigments were prepared via the hydrophobic aggregation of heterogeneous particles in a water medium. The pigment properties of the TiO2-coated barite composite pigments were characterized and evaluated by determining their hiding power, oil absorption value and whiteness. The optical properties were determined by obtaining their UV-vis diffuse reflectance spectra and using the CIE-L*a*b* method. The morphology and bonding properties were investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and infrared spectroscopy (IR). The results show the similarity between the composite pigment and pure rutile TiO2: when the mass ratio of rutile TiO2 in the composite pigment was 60%, the hiding power of the TiO2-coated barite composite pigment was 90.81% of that of pure rutile TiO2. Moreover, the surfaces of the barite particles were uniformly and firmly coated by TiO2, with a hydrophobic association occurring between the hydrophobic carbon chains on the surfaces of barite and TiO2 particles.

Synthesis and colour properties of blue–violet cassiterite pigments doped by terbium ions

This research was focused on the preparation of mixed metal oxide pigments doped with terbium ions with the general formula of Sn0.752Co0.08P0.16Tb0.008O2. These pigments were synthesised by solid-state reactions at high calcination temperatures. The temperature range was chosen from 1350 to 1500 °C. The goal was to develop conditions for the synthesis of this type of pigments and to determine the influence of terbium ions on the colour properties of these compounds. All prepared pigments were applied into the organic matrix and into the ceramic glaze. Thermal behaviours of the reaction mixtures were investigated using differential thermal and thermogravimetric analysis. Synthesised Sn0.752Co0.08P0.16Tb0.008O2 pigments were compared with concurrently prepared pigment Sn0.760Co0.08P0.16O2 depending on the calcination temperature with respect to the colour properties in CIE L*a*b* colour space, furthermore from the point of particle size distribution and phase composition. All compounds provided blue–violet hues that are stable in ceramic glazes.

Preparation and Characterization of Nanoscale Cobalt Blue Pigment for Ceramic Inkjet Printing by Sol-Gel Self-Propagating Combustion

Cobalt blue pigments were prepared by self-propagating combustion followed by sol-gel method using aluminum nitrate and cobalt nitrate as the raw material. X ray diffraction (XRD), scanning electron microscopy (SEM), fiber optic spectrometer and colorimetric analysis were used to investigate the effect of reaction temperature, metal ion concentration and dispersant upon the gel formation. The results show that the formation of gel network could be promoted by increasing the concentration of metal ion (0.01~0.2 mol/L) and sol-gel reaction temperature (80~90°C), and the disper-sibility and stability of the pigment powder could be improved with dispersing agent. The dried gel precursor was calcined at 1250 °C to form 200~500 nm cobalt aluminum with spinel structure with highly negative value of b*.

Clariant completes colour range of “super transparent” pigment preparations, and unveils Hostatint UV range for radiation cured coating systems

Clariant completes colour range of “super transparent” pigment preparations, and unveils Hostatint UV range for radiation cured coating systems

Energy Efficiency in the Microwave-Assisted Solid-State Synthesis of Cobalt Aluminate Pigment

Abstract: Due to their rapid, selective, and volumetric heating, microwaves have been widely used in the past to enhance solid-state reactions as well as the synthesis of ceramic pigments. The aim of this work is to present a case study involving the preparation of blue CoAl2O4 pigment using different microwave applicators and generator frequencies, showing the advantages which can derive from a properly designed microwave reactor for the solid-state synthesis of such pigment. The results show that, when using a properly designed microwave applicator, the specific energy consumption can be significantly lowered compared to conventional heating techniques. Consistently with the data on the dielectric properties of precursors found in literature, the microwave processing of cobalt oxide and aluminum hydroxide mixtures resulted more favorable at 2.45 GHz than at 5.8 GHz microwave frequency.

Synthesis of interference pigments and their application in printing textile materials

The paper considers the potential applications of interference pigments for artistic and coloristic decoration of textiles made of synthetic fibers. A method for the preparation of interference pigments on the basis of silicon dioxide with metal oxide nanolayers was developed. The synthesized pigment was used to print patterns, and evidence was obtained for their high quality and ability to increase the strength of the fiber material.

Stable Benzacridine Pigments by Oxidative Coupling of Chlorogenic Acid with Amino Acids and Proteins: Toward Natural Product-Based Green Food Coloring.

The occasional greening of sweet potatoes and other plant tissues observed during cooking or other food processing has been shown to arise from the autoxidative coupling of chlorogenic acid (CGA, 5-caffeoylquinic acid) with amino acid components, leading to trihydroxybenzacridine pigments. To explore the potential of this reaction for food coloring, we report herein the optimized biomimetic preparation of trihydroxybenzacridine pigments from CGA and amino acids such as glycine and lysine, their straightforward purification by gel filtration chromatography, the UHPLC-MS/MS analysis of the purified pigment fraction, and a detailed characterization of the pH-dependent trihydroxybenzacridine chromophore. Similar green pigments were also obtained by analogous reaction of CGA with a low-cost protein, bovine serum albumin, and by simply adding CGA to chicken egg white (CEW) under stirring. Neither the purified pigments from amino acids nor the pigmented CEW exerted significant toxicity against two human cell lines, Caco-2 and HepG2, at doses compatible with common use in food coloring. Additions of the pure pigments or pigmented CEW to different food matrices imparted intense green hues, and the thermal stability of these preparations proved satisfactory up to 90 °C. The potential application of the greening reaction for the sensing of fish deterioration is also disclosed.

Bernardo Cesi (Cæsius) and his Mineralogia (1636): naming a new science from an indiscriminate piling of mineral accounts

The word Mineralogia appears for the first time in print on the title page of the unfinished book on minerals written in Latin by the Jesuit Bernardo Cesi (Bernardus Caesius Mutinensis: 1581–1630), edited by the Modena Jesuit College and published posthumously in Lyon (France) in 1636. In the opening page of this ponderous in-folio book, Cesi states that he coined the word because he did not want to compete with the title De mineralibus given by the publisher to Albert the Great’s book on the same matter. Moreover, he had thought that such a new word is pleasant and would attract readers to learn the miracles of metal concretions and mineral medicaments, the value of the earths, the preparation of colours and pigments, the effectiveness of condensed juices, the grading of common stones and gemstones, and all the metal riches hidden under the earth. In fact, Mineralogia is a meticulous compilation of all accounts on minerals reported from Homer to Giovan Battista Della Porta (both mentioned by name), i.e., over 2000 years of surviving written texts. Cesi discusses all information according to a strict adherence to Scholasticism, as interpreted by the Jesuit Company at the beginning of seventeenth century. Thus, e.g., the twelve gems of the breastplate of the Jewish High Priest refer to the Apostles and those in the Book of Revelation are in connection with the Nicaean symbol. Cesi either denies or discredits all scientific novelties arising from the contemporaneous “scientific revolution”. In particular, for him the Earth is the fixed centre of the universe; Copernicus is as a drunkard and Galileo as a mere builder of instruments. Nevertheless, he questions the equality in number between metals and planets, suggested by Agricola, because Jesuit scientists had confirmed the existence of four additional planets around Jupiter. This ponderous book is valuable only for its enormous collection of ancient information, which is easy to retrieve because the index is extraordinary meticulous. However, its approach is too backward even for the time it was printed. Consequently, the book was not successful and never re-edited. Only a few English scholars took notice of it, and blamed its approach. After one century, the Swedish school of chemically oriented mineralogists re-vitalized the word Mineralogia. von Bromell (1740) was the first, followed by Wallerius (1747). Probably they did not know Cesi’s book, but both liked and used the Latin name of the science. The word became rooted in terminology and nomenclature when d’Holbach translated into French Wallerius’ textbook (1753). Therefore, from the second half of the eighteenth century on, the French word Mineralogie was the actual root name of the science of minerals for most languages, and gave rise to several derivatives, just as Geologie was the root name for the Earth science in general. The original words Mineralogia (in Latin) and Giologia (in Italian) remained only in the memory of few historians.

Nano-TiO2-SiO2 powder as inorganic support for hybrid pigment preparation

A study was made of the adsorption of three selected food dyes (C.I. Food Black 1, C.I. Food Brown 3 and C.I. Food Green 4) on the surface of an inorganic, synthetic TiO2-SiO2 support of anatase form. This produces new hybrid pigments having desirable physicochemical and functional properties due to the presence in their structure of the TiO2-SiO2 support. The process of adsorption was conducted for dye concentrations ranging from 10 to 50mg/dm3. The physicochemical properties of the inorganic support and the resulting hybrid pigments were determined. The characterisation included determination of the dispersion and morphology of the systems (particle size distribution, SEM images), porous structure parameters (BET isotherms) and electrokinetic properties (zeta potential and electrophoretic mobility), as well as thermal stability and colorimetric parameters. The efficiency of food dye adsorption on TiO2-SiO2 was examined, and the degree of coverage of the inorganic support with the food dyes was also estimated based on elemental analysis results. The results were used to evaluate the quality of the functional hybrid pigments obtained using selected food dyes and TiO2-SiO2 support, and to determine how the adsorption efficiency is affected by the dye structure. Selected diazo food dyes were more effectively adsorbed on the surface of the synthetic TiO2-SiO2 support. The hybrid pigments obtained have desirable physicochemical and functional properties. The synthesised food dye/TiO2-SiO2 hybrids may be used in pharmaceutical products.

Extraction, preparation and application of pigments from Cordyline fruticosa and Hylocereus polyrhizus as sensitizers for dye-sensitized solar cells

Current study employs mixture of chlorophyll-anthocyanin dye extracted from leaves of Cordyline fruticosa as new sensitizers for dye-sensitized solar cell (DSSCs), as well as betalains dye obtained from fruit of Hylocereus polyrhizus. Among ten pigments solvents, the ethanol and methanol extracts revealed higher absorption spectra of pigments extracted from C. fruticosa and H. polyrhizus respectively. A major effect of temperature increase was studied to increase the extraction yield. The results indicated that extraction temperature between 70 and 80°C exhibited a high dye concentration of each plant than other temperatures. The optimal temperature was around 80°C and there was a sharp decrease of dye concentration at temperatures higher than this temperature. According to experimental results, the conversion efficiency of DSSC fabricated by mixture of chlorophyll and anthocyanin dyes from C. fruticosa leaves is 0.5% with short-circuit current (Isc) of 1.3mA/cm−2, open-circuit voltage (Voc) of 0.62V and fill factor (FF) of 60.16%. The higher photoelectric conversion efficiency of the DSSC prepared from the extract of H. polyrhizus was 0.16%, with Voc of 0.5V, Isc of 0.4mA/cm−2 and FF of 79.16%. The DSSC based betalain dye extracted from fruit of H. polyrhizus shows higher maximum IPCE of 44% than that of the DSSCs sensitized with mixed chlorophyll-anthocyanin dye from C. fruticosa (42%).

Controlled Preparation and Characterization of Titanium Series Functional Pigment and its Application in Coatings

In our recent work, we synthesize several spherical rutile TiO2 powders with different average particle size though hydrothermal method using TiCl4 under lower temperature in a shorter reaction period. Afterwards, solar heat-reflection coatings were prepared by using the TiO2 as pigment. The TiO2 powders were characterized by XRD to determine the phase of crystal. The morphology and particle size were observed by using SEM, and the spectral reflectance of the powder samples and coatings were measured using UV/VIS/NIR spectrophotometer. In order to measure the temperature on the back of coatings, the self-assembled equipment which consisted of solar lamps and surface temperature sensors connected to a data logging system was invented. The test results showed that the shape, average particle size and size distribution were closed-packed state and a bigger mean particle size had higher reflectance intensity. Meanwhile, the reflectance was closely connected to the particle size distribution. Actually, the coatings dispersed TiO2 powder with desired size distribution had excellent performance.

Preparation of sulfur pigments based on the interaction of sulfur with aniline

The article presents the results of obtaining and investigating the various ratios of the components of aniline hydrochloride-S-CaO (Al2O3) 1: 0.4: 0.6; 1: 1: 0.6; 1: 2: 10; 1:10:10 – up to ten times the binding of sulfur and oxides to aniline, having a different color range from dark green to light brown, depending on the composition of the components. In sulfurous composites with various molar ratios of sulfur components, which plays the role of an inorganic filler, it binds almost completely, while remaining chemically inert.