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Transparent Wood Composites
Transparent wood composites are novel wood materials which have up to 90% transparency. Some have better mechanical properties than wood itself. They were made for the first time in 1992. These materials are significantly more biodegradable than glass and plastics. Transparent wood is also shatterproof. History A research group led by Professor Lars Berglund from Swedish KTH University along with a University of Maryland research group led by Professor Liangbing Hu have developed a method to remove the color and some chemicals from small blocks of wood, followed by adding polymers, such as poly(methyl methacrylate) (PMMA) and epoxy, at the cellular level, thereby rendering them transparent. As soon as released in between 2015 and 2016, see-through wood had a large press reaction, with articles in ''ScienceDaily'', ''Wired'', ''The Wall Street Journal'', and ''The New York Times.'' Actually those research groups rediscovered a work from Siegfried Fink, a German Researcher, fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transparency And Translucency
In the field of optics, transparency (also called pellucidity or diaphaneity) is the physical property of allowing light to pass through the material without appreciable scattering of light. On a macroscopic scale (one in which the dimensions are much larger than the wavelengths of the photons in question), the photons can be said to follow Snell's law. Translucency (also called translucence or translucidity) allows light to pass through, but does not necessarily (again, on the macroscopic scale) follow Snell's law; the photons can be scattered at either of the two interfaces, or internally, where there is a change in index of refraction. In other words, a translucent material is made up of components with different indices of refraction. A transparent material is made up of components with a uniform index of refraction. Transparent materials appear clear, with the overall appearance of one color, or any combination leading up to a brilliant spectrum of every color. The opposit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemicellulose
A hemicellulose (also known as polyose) is one of a number of heteropolymer, heteropolymers (matrix polysaccharides), such as arabinoxylans, present along with cellulose in almost all embryophyte, terrestrial plant cell walls.Scheller HV, Ulvskov Hemicelluloses.// Annu Rev Plant Biol. 2010;61:263-89. doi: 10.1146/annurev-arplant-042809-112315. Cellulose is crystalline, strong, and resistant to hydrolysis. Hemicelluloses are branched, shorter in length than cellulose, and also show a propensity to crystallize. They can be hydrolyzed by dilute acid or Base (chemistry), base as well as a myriad of Cellulase, hemicellulase enzymes. Composition Diverse kinds of hemicelluloses are known. Important examples include xylan, glucuronoxylan, arabinoxylan, glucomannan, and xyloglucan. Hemicelluloses are polysaccharides often associated with cellulose, but with distinct compositions and structures. Whereas cellulose is derived exclusively from glucose, hemicelluloses are composed of diverse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Succinic Anhydride
Succinic anhydride, is an organic compound with the molecular formula (CH2CO)2O. This colorless solid is the acid anhydride of succinic acid. Preparation In the laboratory, this material can be prepared by dehydration of succinic acid. Such dehydration can occur with the help of acetyl chloride or phosphoryl chloride, or thermally. Industrially, succinic anhydride is prepared by catalytic hydrogenation of maleic anhydride. Reactions Succinic anhydride hydrolyzes readily to give succinic acid: :(CH2CO)2O + H2O → (CH2CO2H)2 With alcohols (ROH), a similar reaction occurs, delivering the monoester: :(CH2CO)2O + ROH → RO2CCH2CH2CO2H Succinic anhydride is used in acylations under Friedel-Crafts conditions, as illustrated by the industrial route to the drug Fenbufen. Related compounds Maleic anhydride undergoes the Alder-ene reaction with alkenes to give alkenylsuccinic anhydrides. Such compounds are sizing agents in the paper industry. In this role, the anhydride is proposed t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isomerization
In chemistry, isomerization or isomerisation is the process in which a molecule, polyatomic ion or molecular fragment is transformed into an isomer with a different chemical structure. Enolization is an example of isomerization, as is tautomerization. When the isomerization occurs intramolecularly it may be called a rearrangement reaction. When the activation energy for the isomerization reaction is sufficiently small, both isomers will exist in a temperature-dependent equilibrium with each other. Many values of the standard free energy difference, \Delta G^\circ, have been calculated, with good agreement between observed and calculated data. Examples and applications Alkanes Skeletal isomerization occurs in the cracking process, used in the petrochemical industry. As well as reducing the average chain length, straight-chain hydrocarbons are converted to branched isomers in the process, as illustrated the following reaction of ''n''-butane to ''i''-butane. :\overset -> \o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclic Terpene
Cycle, cycles, or cyclic may refer to: Anthropology and social sciences * Cyclic history, a theory of history * Cyclical theory, a theory of American political history associated with Arthur Schlesinger, Sr. * Social cycle, various cycles in social sciences ** Business cycle, the downward and upward movement of gross domestic product (GDP) around its ostensible, long-term growth trend Arts, entertainment, and media Films * ''Cycle'' (2008 film), a Malayalam film * ''Cycle'' (2017 film), a Marathi film Literature * ''Cycle'' (magazine), an American motorcycling enthusiast magazine * Literary cycle, a group of stories focused on common figures Music Musical terminology * Cycle (music), a set of musical pieces that belong together **Cyclic form, a technique of construction involving multiple sections or movements **Interval cycle, a collection of pitch classes generated from a sequence of the same interval class **Song cycle, individually complete songs designed to be performe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acrylate
Acrylates (IUPAC: prop-2-enoates) are the salts, esters, and conjugate bases of acrylic acid. The acrylate ion is the anion C H2=CHC OO−. Often, acrylate refers to esters of acrylic acid, the most common member being methyl acrylate. These acrylates contain vinyl groups. These compounds are of interest because they are bifunctional: the vinyl group is susceptible to polymerization and the carboxylate group carries myriad functionalities. Modified acrylates are also numerous, some examples being methacrylates (CH2=C(CH3)CO2R) and cyanoacrylates (CH2=C(CN)CO2R). Acrylate can also refer to polyacrylates prepared through the polymerization of the vinyl groups of acrylate monomers. File:Acrylate-anion.svg, The acrylate anion File:Trimethylolpropane triacrylate.svg, Trimethylolpropane triacrylate (TMPTA), a trifunctional acrylate ester File:Methylacrylat.svg, Methyl acrylate, an acrylic ester File:Hexandioldiacrylat.svg, Hexandiol diacrylate, a bifunctional acrylate File:Methyl-meth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limonene
Limonene is a colorless liquid aliphatic hydrocarbon classified as a cyclic monoterpene, and is the major component in the oil of citrus fruit peels. The -isomer, occurring more commonly in nature as the fragrance of oranges, is a flavoring agent in food manufacturing. It is also used in chemical synthesis as a precursor to carvone and as a renewables-based solvent in cleaning products. The less common -isomer has a piny, turpentine-like odor, and is found in the edible parts of such plants as caraway, dill, and bergamot orange plants. Limonene takes its name from Italian ''limone'' ("lemon"). Limonene is a chiral molecule, and biological sources produce one enantiomer: the principal industrial source, citrus fruit, contains -limonene ((+)-limonene), which is the (''R'')-enantiomer. Racemic limonene is known as dipentene. -Limonene is obtained commercially from citrus fruits through two primary methods: centrifugal separation or steam distillation. Chemical reactions Limon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monomer
In chemistry, a monomer ( ; ''mono-'', "one" + '' -mer'', "part") is a molecule that can react together with other monomer molecules to form a larger polymer chain or three-dimensional network in a process called polymerization. Classification Monomers can be classified in many ways. They can be subdivided into two broad classes, depending on the kind of the polymer that they form. Monomers that participate in condensation polymerization have a different stoichiometry than monomers that participate in addition polymerization: : Other classifications include: *natural vs synthetic monomers, e.g. glycine vs caprolactam, respectively *polar vs nonpolar monomers, e.g. vinyl acetate vs ethylene, respectively *cyclic vs linear, e.g. ethylene oxide vs ethylene glycol, respectively The polymerization of one kind of monomer gives a homopolymer. Many polymers are copolymers, meaning that they are derived from two different monomers. In the case of condensation polymerizations, the r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methyl Methacrylate
Methyl methacrylate (MMA) is an organic compound with the formula CH2=C(CH3)COOCH3. This colorless liquid, the methyl ester of methacrylic acid (MAA), is a monomer produced on a large scale for the production of poly(methyl methacrylate) (PMMA). Production and properties Given the scale of production, many methods have been developed starting from diverse two- to four-carbon precursors.. Two principal routes appear to be commonly practiced. Cyanohydrin route The compound is manufactured by several methods, the principal one being the acetone cyanohydrin (ACH) route. ACH is produced by condensation of acetone and hydrogen cyanide. The cyanohydrin is hydrolyzed in the presence of sulfuric acid to a sulfate ester of the methacrylamide. Methanolysis of this ester gives ammonium bisulfate and MMA. Although widely used, the ACH route coproduces substantial amounts of ammonium sulfate. :(CH3)2CO + HCN → (CH3)2C(OH)CN :(CH3)2C(OH)CN + H2SO4 → (CH3)2C(OSO3H)C(O)NH2. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Peroxide
Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscous than water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution (3%–6% by weight) in water for consumer use, and in higher concentrations for industrial use. Concentrated hydrogen peroxide, or " high-test peroxide", decomposes explosively when heated and has been used as a propellant in rocketry. Hydrogen peroxide is a reactive oxygen species and the simplest peroxide, a compound having an oxygen–oxygen single bond. It decomposes slowly when exposed to light, and rapidly in the presence of organic or reactive compounds. It is typically stored with a stabilizer in a weakly acidic solution in a dark bottle to block light. Hydrogen peroxide is found in biological systems including the human body. Enzymes that use or decompose hydrogen peroxide are classified as peroxidases. Properties The boiling poi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Sulfite
Sodium sulfite (sodium sulphite) is the inorganic compound with the chemical formula Na2 SO3. A white, water-soluble solid, it is used commercially as an antioxidant and preservative. A heptahydrate is also known but it is less useful because of its greater susceptibility toward oxidation by air. Preparation Sodium sulfite can be prepared by treating a solution of sodium hydroxide with sulfur dioxide. When conducted in warm water, Na2SO3 initially precipitates as a white solid. With more SO2, the solid dissolves to give the disulfite, which crystallizes upon cooling. :SO2 + 2 NaOH -> Na2SO3 + H2O Sodium sulfite is made industrially by treating sulfur dioxide with a solution of sodium carbonate. The overall reaction is: :SO2 + Na2CO3 -> Na2SO3 + CO2 Applications Sodium sulfite is primarily used in the pulp and paper industry. It has been also applied in the thermomechanical conversion of wood to fibres (''defibration'') for producing medium density fibreboards (M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Hydroxide
Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula NaOH. It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly caustic base and alkali that decomposes proteins at ordinary ambient temperatures and may cause severe chemical burns. It is highly soluble in water, and readily absorbs moisture and carbon dioxide from the air. It forms a series of hydrates . The monohydrate crystallizes from water solutions between 12.3 and 61.8 °C. The commercially available "sodium hydroxide" is often this monohydrate, and published data may refer to it instead of the anhydrous compound. As one of the simplest hydroxides, sodium hydroxide is frequently used alongside neutral water and acidic hydrochloric acid to demonstrate the pH scale to chemistry students. Sodium hydroxide is used in many industries: in the manufacture of pulp and paper, textiles, drinking water, soaps and deterge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
