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Mordant
A mordant or dye fixative is a substance used to set (i.e., bind) dyes on fabrics. It does this by forming a coordination complex with the dye, which then attaches to the fabric (or tissue). It may be used for dyeing fabrics or for intensifying stains in cell or tissue preparations. Although mordants are still used, especially by small batch dyers, they have been largely displaced in industry by substantive dyes.} The term mordant comes from the Latin ''mordere'', "to bite". In the past, it was thought that a mordant helped the dye "bite" onto the fiber so that it would hold fast during washing. A mordant is often a polyvalent metal ion, and one example is chromium (III). The resulting coordination complex of dye and ion is colloidal and can be either acidic or alkaline. Common dye mordants Mordants include tannic acid, oxalic acid, alum, chrome alum, sodium chloride, and certain salts of aluminium, chromium, copper, iron, iodine, potassium, sodium, tungsten, and tin. Io ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lake Pigment
A lake pigment is a pigment made by precipitating a dye with an chemically inert, inert binder (material), binder, or mordant, usually a metallic salt. Lake pigments are largely organic compound, chemically organic.K. Hunger. W. Herbst "Pigments, Organic" in ''Ullmann's Encyclopedia of Industrial Chemistry'', Wiley-VCH, Weinheim, 2012. Manufacturers and suppliers to artists and industry frequently omit the ''lake'' designation in the name. Many lake pigments are Fugitive pigment, fugitive because the dyes involved are not lightfast. Red lakes were particularly important in Renaissance art, Renaissance and Baroque art, Baroque paintings; they were often used as translucent glazes to portray the colors of rich fabrics and draperies.David Bomford and Ashok Roy, ''A Closer Look - Colour'', National Gallery Company, p. 41. Etymology The term ''lake'' is derived from the term Lac (resin), ''lac'', the secretions of the Indian wood insect ''Kerria lacca'' (formerly ''Laccifer lacca'' or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aluminium
Aluminium (or aluminum in North American English) is a chemical element; it has chemical symbol, symbol Al and atomic number 13. It has a density lower than that of other common metals, about one-third that of steel. Aluminium has a great affinity towards oxygen, passivation (chemistry), forming a protective layer of aluminium oxide, oxide on the surface when exposed to air. It visually resembles silver, both in its color and in its great ability to reflect light. It is soft, magnetism, nonmagnetic, and ductility, ductile. It has one stable isotope, 27Al, which is highly abundant, making aluminium the abundance of the chemical elements, 12th-most abundant element in the universe. The radioactive decay, radioactivity of aluminium-26, 26Al leads to it being used in radiometric dating. Chemically, aluminium is a post-transition metal in the boron group; as is common for the group, aluminium forms compounds primarily in the +3 oxidation state. The aluminium cation Al3+ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tannic Acid
Tannic acid is a specific form of tannin, a type of polyphenol. Its weak acidity (Acid dissociation constant, pKa around 6) is due to the numerous phenol groups in the structure. The chemical formula for commercial tannic acid is often given as C76H52O46, which corresponds with decagalloyl glucose, but in fact it is a mixture of polygalloyl glucoses or polygalloyl quinic acid esters with the number of gallic acid, galloyl moieties per molecule ranging from 2 up to 12 depending on the plant source used to extract the tannic acid. Commercial tannic acid is usually extracted from any of the following plant parts: Tara pods (''Caesalpinia spinosa''), gallnuts from ''Rhus semialata'' or ''Quercus infectoria'' or Sicilian sumac leaves (''Rhus coriaria''). According to the definitions provided in external references such as international pharmacopoeia, Food Chemicals Codex and FAO-WHO tannic acid monograph only tannins obtained from the above-mentioned plants can be considered as tanni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gram Staining
Gram stain (Gram staining or Gram's method), is a method of staining used to classify bacterial species into two large groups: gram-positive bacteria and gram-negative bacteria. It may also be used to diagnose a fungal infection. The name comes from the Danish bacteriologist Hans Christian Gram, who developed the technique in 1884. Gram staining differentiates bacteria by the chemical and physical properties of their cell walls. Gram-positive cells have a thick layer of peptidoglycan in the cell wall that retains the primary stain, crystal violet. Gram-negative cells have a thinner peptidoglycan layer that allows the crystal violet to wash out on addition of ethanol. They are stained pink or red by the counterstain, commonly safranin or fuchsine. Lugol's iodine solution is always added after addition of crystal violet to form a stable complex with crystal violet that strengthens the bonds of the stain with the cell wall. Gram staining is almost always the first step in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alum
An alum () is a type of chemical compound, usually a hydrated double salt, double sulfate salt (chemistry), salt of aluminium with the general chemical formula, formula , such that is a valence (chemistry), monovalent cation such as potassium or ammonium. By itself, "alum" often refers to potassium alum, with the formula . Other alums are named after the monovalent ion, such as sodium alum and ammonium alum. The name "alum" is also used, more generally, for salts with the same formula and structure, except that aluminium is replaced by another Valence (chemistry), trivalent metal ion like chromium#Chromium(III), chromium, or sulfur is replaced by another chalcogen like selenium. The most common of these analogs is chrome alum . In most industries, the name "alum" (or "papermaker's alum") is used to refer to aluminium sulfate, , which is used for most industrial flocculation (the variable is an integer whose size depends on the amount of water absorbed into the alum). For medi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Substantive Dye
A substantive dye or direct dye is a dye that adheres to its substrate, typically a textile, by non-ionic forces. Overview The amount of this attraction is known as "substantivity": the higher the substantivity the greater the attraction of the dye for the fiber. Substantive dyes work best on textiles with high contents of cellulose, such as cotton. In contrast to direct dyes, wool and leather goods are dyed by the process of ion exchange, exploiting the cationic nature of proteins near neutral pH. The development of substantive dyes helped make mordant dyes obsolete. Substantive dyes are set in a slightly basic or neutral environment at temperatures close to boiling point. They are set by formation of aggregates of dyes within interstices of the fibres. Aggregation is enhanced by extended aromatic rings.Klaus Hunger, Peter Mischke, Wolfgang Rieper, Roderich Raue, Klaus Kunde, Aloys Engel. "Azo Dyes". ''Ullmann's Encyclopedia of Industrial Chemistry''. Weinheim: Wiley-VCH . Gal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromium
Chromium is a chemical element; it has Symbol (chemistry), symbol Cr and atomic number 24. It is the first element in Group 6 element, group 6. It is a steely-grey, Luster (mineralogy), lustrous, hard, and brittle transition metal. Chromium is valued for its high corrosion resistance and hardness. A major development in steel production was the discovery that steel could be made highly resistant to corrosion and discoloration by adding metallic chromium to form stainless steel. Stainless steel and chrome plating (electroplating with chromium) together comprise 85% of the commercial use. Chromium is also greatly valued as a metal that is able to be highly polishing, polished while resisting tarnishing. Polished chromium reflects almost 70% of the visible spectrum, and almost 90% of infrared, infrared light. The name of the element is derived from the Ancient Greek, Greek word χρῶμα, ''chrōma'', meaning color, because many chromium compounds are intensely colored. Indust ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxalic Acid
Oxalic acid is an organic acid with the systematic name ethanedioic acid and chemical formula , also written as or or . It is the simplest dicarboxylic acid. It is a white crystalline solid that forms a colorless solution in water. Its name is derived from early investigators who isolated oxalic acid from flowering plants of the genus '' Oxalis'', commonly known as wood-sorrels. It occurs naturally in many foods. Excessive ingestion of oxalic acid or prolonged skin contact can be dangerous. Oxalic acid is a much stronger acid than acetic acid. It is a reducing agent and its conjugate bases hydrogen oxalate () and oxalate () are chelating agents for metal cations. It is used as a cleaning agent, especially for the removal of rust, because it forms a water-soluble ferric iron complex, the ferrioxalate ion. Oxalic acid typically occurs as the dihydrate with the formula . History The preparation of salts of oxalic acid from plants had been known since at least 1745, when ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mordant Red 19
Mordant red 19 is an organic compound with the chemical formula C16H13ClN4O5S. It is classified as an azo dye.Klaus Hunger, Peter Mischke, Wolfgang Rieper, Roderich Raue, Klaus Kunde, Aloys Engel: "Azo Dyes" in ''Ullmann’s Encyclopedia of Industrial Chemistry'', 2005, Wiley-VCH, Weinheim.. It is a mordant used in textile dyeing, usually in combination with chromium. It is usually found as the sodium salt. See also *Alizarin *List of colors These are the lists of colors; * List of colors: A–F * List of colors: G–M * List of colors: N–Z * List of colors (alphabetical) * List of colors by shade * List of color palettes * List of Crayola crayon colors * List of RAL colours * List o ... References External linksGoogle images of Mordant Red 19 Shades of red Azo dyes Pyrazolones Sulfonic acids Chloroarenes Phenols {{Carbohydrate-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metal
A metal () is a material that, when polished or fractured, shows a lustrous appearance, and conducts electrical resistivity and conductivity, electricity and thermal conductivity, heat relatively well. These properties are all associated with having electrons available at the Fermi level, as against nonmetallic materials which do not. Metals are typically ductile (can be drawn into a wire) and malleable (can be shaped via hammering or pressing). A metal may be a chemical element such as iron; an alloy such as stainless steel; or a molecular compound such as polythiazyl, polymeric sulfur nitride. The general science of metals is called metallurgy, a subtopic of materials science; aspects of the electronic and thermal properties are also within the scope of condensed matter physics and solid-state chemistry, it is a multidisciplinary topic. In colloquial use materials such as steel alloys are referred to as metals, while others such as polymers, wood or ceramics are nonmetallic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copper
Copper is a chemical element; it has symbol Cu (from Latin ) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orange color. Copper is used as a conductor of heat and electricity, as a building material, and as a constituent of various metal alloys, such as sterling silver used in jewelry, cupronickel used to make marine hardware and coins, and constantan used in strain gauges and thermocouples for temperature measurement. Copper is one of the few metals that can occur in nature in a directly usable, unalloyed metallic form. This means that copper is a native metal. This led to very early human use in several regions, from . Thousands of years later, it was the first metal to be smelted from sulfide ores, ; the first metal to be cast into a shape in a mold, ; and the first metal to be purposely alloyed with another metal, tin, to create bronze, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cochineal
The cochineal ( , ; ''Dactylopius coccus'') is a scale insect in the suborder Sternorrhyncha, from which the natural dye carmine is derived. A primarily sessility (motility), sessile parasitism, parasite native to tropical and subtropical South America through North America (Mexico and the Southwest United States), this insect lives on Cactus, cacti in the genus ''Opuntia'', feeding on plant moisture and nutrients. The insects are found on the pads of prickly pear cacti, collected by brushing them off the plants, and dried. The insect produces carminic acid that deters predation by other insects. Carminic acid, typically 17–24% of dried insects' weight, can be extracted from the body and eggs, then mixed with aluminium or calcium salts to make carmine dye, also known as cochineal. Today, carmine is primarily used as a Food coloring, colorant in food and in lipstick (Carmine, E120 or Carminic acid, Natural Red 4). Carmine dye was used in the Americas for coloring fabrics and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
