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Polyethylene Naphthalate
Polyethylene naphthalate (poly(ethylene 2,6-naphthalate) or PEN) is a polyester derived from naphthalene-2,6-dicarboxylic acid and ethylene glycol. As such it is related to poly(ethylene terephthalate), but with superior barrier properties. Production Two major manufacturing routes exist for polyethylene naphthalate (PEN), i.e. an ester or an acid process, named according to whether the starting monomer is a diester or a diacid derivative, respectively. In both cases for PEN, the glycol monomer is ethylene glycol. Solid-state polymerization (SSP) of the melt-produced resin pellets is the preferred process to increase the average molecular weight of PEN. Applications Because it provides a very good oxygen barrier, it is well-suited for bottling beverages that are susceptible to oxidation, such as beer. It is also used in making high performance sailcloth. Significant commercial markets have been developed for its application in textile and industrial fibers, films, and foamed a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyester
Polyester is a category of polymers that contain the ester functional group in every repeat unit of their main chain. As a specific material, it most commonly refers to a type called polyethylene terephthalate (PET). Polyesters include naturally occurring chemicals, such as in plants and insects, as well as synthetics such as polybutyrate. Natural polyesters and a few synthetic ones are biodegradable, but most synthetic polyesters are not. Synthetic polyesters are used extensively in clothing. Polyester fibers are sometimes spun together with natural fibers to produce a cloth with blended properties. Cotton-polyester blends can be strong, wrinkle- and tear-resistant, and reduce shrinking. Synthetic fibers using polyester have high water, wind and environmental resistance compared to plant-derived fibers. They are less fire-resistant and can melt when ignited. Liquid crystalline polyesters are among the first industrially used liquid crystal polymers. They are used f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2,6-Naphthalenedicarboxylic Acid
2,6-Naphthalenedicarboxylic acid is an organic compound with the formula C10H6(CO2H)2. This colorless solid is one of several isomers of naphthalenedicarboxylic acid. It is a precursor to the high performance polyester polyethylene naphthalate (PEN, poly(ethylene-2,6-naphthalene dicarboxylate)). It is also used in the synthesis of some metal-organic frameworks. Preparation The conjugate base of 2,6-naphthalenedicarboxylic acid, when heated, isomerizes to the 1,6-isomer, which is readily converted to 1,6-naphthalenedicarboxylic acid. It is also produced by oxidation of 2,6-diisopropylnaphthalene 2,6-Diisopropylnaphthalene (2,6-DIPN) is an organic compound with the formula C10H6(i-Pr)2 (where i-Pr = isopropyl). 2,6-DIPN is one of several isomers of diisopropylnaphthalene. It is a white or colorless solid.. 2,6-DIPN is plant growth regulat ..... References Dicarboxylic acids Naphthalenes {{aromatic-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethylene Glycol
Ethylene glycol ( IUPAC name: ethane-1,2-diol) is an organic compound (a vicinal diol) with the formula . It is mainly used for two purposes, as a raw material in the manufacture of polyester fibers and for antifreeze formulations. It is an odorless, colorless, flammable, viscous liquid. Ethylene glycol has a sweet taste, but it is toxic in high concentrations. Production Industrial routes Ethylene glycol is produced from ethylene (ethene), via the intermediate ethylene oxide. Ethylene oxide reacts with water to produce ethylene glycol according to the chemical equation: This reaction can be catalyzed by either acids or bases, or can occur at neutral pH under elevated temperatures. The highest yields of ethylene glycol occur at acidic or neutral pH with a large excess of water. Under these conditions, ethylene glycol yields of 90% can be achieved. The major byproducts are the oligomers diethylene glycol, triethylene glycol, and tetraethylene glycol. The separation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Derivative (chemistry)
In chemistry, a derivative is a compound that is derived from a similar compound by a chemical reaction. In the past, derivative also meant a compound that ''can be imagined to'' arise from another compound, if one atom or group of atoms is replaced with another atom or group of atoms, but modern chemical language now uses the term structural analog for this meaning, thus eliminating ambiguity. The term "structural analogue" is common in organic chemistry. In biochemistry, the word is used for compounds that at least theoretically can be formed from the precursor compound. Chemical derivatives may be used to facilitate analysis. For example, melting point (MP) analysis can assist in identification of many organic compounds. A crystalline derivative may be prepared, such as a semicarbazone or 2,4-dinitrophenylhydrazone (derived from aldehydes or ketones), as a simple way of verifying the identity of the original compound, assuming that a table of derivative MP values is avai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beer
Beer is one of the oldest and the most widely consumed type of alcoholic drink in the world, and the third most popular drink overall after water and tea. It is produced by the brewing and fermentation of starches, mainly derived from cereal grains—most commonly from malted barley, though wheat, maize (corn), rice, and oats are also used. During the brewing process, fermentation of the starch sugars in the wort produces ethanol and carbonation in the resulting beer.Barth, Roger. ''The Chemistry of Beer: The Science in the Suds'', Wiley 2013: . Most modern beer is brewed with hops, which add bitterness and other flavours and act as a natural preservative and stabilizing agent. Other flavouring agents such as gruit, herbs, or fruits may be included or used instead of hops. In commercial brewing, the natural carbonation effect is often removed during processing and replaced with forced carbonation. Some of humanity's earliest known writings refer to the productio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sailcloth
Sailcloth encompasses a wide variety of materials that span those from natural fibers, such as flax, hemp or cotton in various forms of sail canvas, to synthetic fibers, including nylon, polyester, aramids, and carbon fibers in a variety of woven, spun and molded textiles. History Western traditions Viking longships used wool for sailcloth. The cloth was woven in one of three ways, according to locality and tradition: plain weave with individual threads going over and under each other, three-shaft twill with two threads going over and under at each cross thread, and four-shaft twill with thread interwoven with two threads at a time in either direction. Such was the practice from the 11th through the 14th centuries. Doek is Dutch for cloth, which evolved into the English word "duck" in reference to sail canvas. Duck was typically made from cotton or linen (flax), with some use of hemp. These natural fibers have poor resistance to rot, UV light and water absorption. Linen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Advanced Photo System
Advanced Photo System (APS) is a discontinued film format for still photography first produced in 1996. It was marketed by Eastman Kodak under the brand name Advantix, by FujiFilm under the name Nexia, by Agfa under the name Futura and by Konica as Centuria. Design The film is 24 mm wide, and has three image formats: * H for "High Definition" (30.2 × 16.7 mm; aspect ratio 16:9; 4×7" print) (1.25 crop compared to 36x24mm full frame) * C for "Classic" (25.1 × 16.7 mm; aspect ratio 3:2; 4×6" print) (1.44 crop compared to 36x24mm full frame) * P for " Panoramic" (30.2 × 9.5 mm; aspect ratio 3:1; 4×11" print) (1.36 crop compared to 36x24mm full frame) The "C" and "P" formats are formed by cropping the 30.2 × 16.7 mm "High Definition" image. The full image is recorded on the film, and an image recorded in one aspect ratio can be reprinted in another. The "C" format has an equivalent aspect ratio to a 135 film image. Most APS cameras (wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linear Tape-Open
Linearity is the property of a mathematical relationship ('' function'') that can be graphically represented as a straight line. Linearity is closely related to '' proportionality''. Examples in physics include rectilinear motion, the linear relationship of voltage and current in an electrical conductor ( Ohm's law), and the relationship of mass and weight. By contrast, more complicated relationships are ''nonlinear''. Generalized for functions in more than one dimension, linearity means the property of a function of being compatible with addition and scaling, also known as the superposition principle. The word linear comes from Latin ''linearis'', "pertaining to or resembling a line". In mathematics In mathematics, a linear map or linear function ''f''(''x'') is a function that satisfies the two properties: * Additivity: . * Homogeneity of degree 1: for all α. These properties are known as the superposition principle. In this definition, ''x'' is not necessarily ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scintillator
A scintillator is a material that exhibits scintillation, the property of luminescence, when excited by ionizing radiation. Luminescent materials, when struck by an incoming particle, absorb its energy and scintillate (i.e. re-emit the absorbed energy in the form of light). Sometimes, the excited state is metastable, so the relaxation back down from the excited state to lower states is delayed (necessitating anywhere from a few nanoseconds to hours depending on the material). The process then corresponds to one of two phenomena: delayed fluorescence or phosphorescence. The correspondence depends on the type of transition and hence the wavelength of the emitted optical photon. Principle of operation A scintillation detector or scintillation counter is obtained when a scintillator is coupled to an electronic light sensor such as a photomultiplier tube (PMT), photodiode, or silicon photomultiplier. PMTs absorb the light emitted by the scintillator and re-emit it in the form o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Europhysics Letters
''EPL'' is a peer-reviewed scientific journal published by EDP Sciences, IOP Publishing and the Italian Physical Society on behalf of the European Physical Society and 17 other European physical societies. Prior to 1 January 2007 it was known as ''Europhysics Letters''. Scope ''EPL'' publishes original letters that communicates new results and findings that merit rapid publication in all areas of physics. ''EPL'' also publishes comments on letters previously published in the journal. History ''Europhysics Letters'' was founded in 1986 by the European Physical Society (EPS), Société Française de Physique (SFP) and its subsidiary EDP Sciences, the Società Italiana di Fisica (SIF) and the Institute of Physics (IOP). The new journal incorporated '' Lettere al Nuovo Cimento'' and '' Journal de Physique: Lettres'' and was published by EPS, EDP Sciences and SIF until 2006. ''EPL'' is now published under the scientific policy and control of the EPS by EDP Sciences, IOP Publishi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyethylene Terephthalate
Polyethylene terephthalate (or poly(ethylene terephthalate), PET, PETE, or the obsolete PETP or PET-P), is the most common thermoplastic polymer resin of the polyester family and is used in fibres for clothing, containers for liquids and foods, and thermoforming for manufacturing, and in combination with glass fibre for engineering resins. In 2016, annual production of PET was 56 million tons. The biggest application is in fibres (in excess of 60%), with bottle production accounting for about 30% of global demand. In the context of textile applications, PET is referred to by its common name, polyester, whereas the acronym ''PET'' is generally used in relation to packaging. Polyester makes up about 18% of world polymer production and is the fourth-most-produced polymer after polyethylene (PE), polypropylene (PP) and polyvinyl chloride (PVC). PET consists of repeating (C10H8O4) units. PET is commonly recycled, and has the digit 1 (♳) as its resin identification code (R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyesters
Polyester is a category of polymers that contain the ester functional group in every repeat unit of their main chain. As a specific material, it most commonly refers to a type called polyethylene terephthalate (PET). Polyesters include naturally occurring chemicals, such as in plants and insects, as well as synthetics such as polybutyrate. Natural polyesters and a few synthetic ones are biodegradable, but most synthetic polyesters are not. Synthetic polyesters are used extensively in clothing. Polyester fibers are sometimes spun together with natural fibers to produce a cloth with blended properties. Cotton-polyester blends can be strong, wrinkle- and tear-resistant, and reduce shrinking. Synthetic fibers using polyester have high water, wind and environmental resistance compared to plant-derived fibers. They are less fire-resistant and can melt when ignited. Liquid crystalline polyesters are among the first industrially used liquid crystal polymers. They are used for the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
