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Encyclopedia > Polyoxymethylene

Polyoxymethylene (POM), also known as acetal resin, polytrioxane, polyformaldehyde, and paraformaldehyde, is an engineering plastic used to make gears, bushings and other mechanical parts (cf. nylon, teflon, UHMWPE). The most important polyacetal resin, it is a thermoplastic with good physical and processing properties. It is also sold under the trade names Delrin, Kepital, Celcon, "Hostaform" and Ultraform, the last three being copolymers. Its chemical formula is -(-O-CH2-)n-. Image File history File links Please see the file description page for further information. ... It has been suggested that this article or section be merged into polyoxymethylene. ... Image File history File links Download high-resolution version (2064x1318, 18 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Polyoxymethylene ... Image File history File links Download high-resolution version (2064x1318, 18 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Polyoxymethylene ... Engineering plastics are plastics which regain their original shape after deformation. ... Spur gears found on a piece of farm equipment. ... It has been suggested that Bushing be merged into this article or section. ... Nylon represents a family of synthetic polymers, a thermoplastic material, first produced on February 28, 1935 by Gerard J. Berchet of Wallace Carothers research group at DuPont. ... Teflon is polytetrafluoroethylene (PTFE), a polymer of fluorinated ethylene. ... Ultra high molecular weight polyethylene (UHMWPE), also known as high modulus polyethylene (HMPE) or high performance polyethylene (HPPE), is a thermoplastic made from oil. ... An acetal is a functional group or molecule containing the functional group of a carbon bonded to two -OR groups. ... A thermoplastic is a material that is plastic or deformable, melts to a liquid when heated and freezes to a brittle, glassy state when cooled sufficiently. ... A trade name, also known as a trading name or a business name, is the legal name of a business, or the name which a business trades under for commercial purposes. ... It has been suggested that this article or section be merged into polyoxymethylene. ... A heteropolymer, also called a copolymer, is a polymer formed when two different types of monomer are linked in the same polymer chain. ...


Long molecules of this compound are also found in formalin preserving solutions. Since formaldehyde polymerizes in water, formalin contains very little formaldehyde in the form of H2CO monomer; most of it forms short chains of polyformaldehyde. A few percent methanol is often added to limit the extent of polymerization. The chemical compound formaldehyde (also known as methanal), is a gas with a strong pungent smell. ... methanol is also used to fuel speedway bikes. ... This is the article about the process. ...


Synthesis

To make polyoxymethylene homopolymer, anhydrous formaldehyde must be generated. The principal method is by reaction of the aqueous formaldehyde with an alcohol to create a hemiformal, dehydration of the hemiformal/water mixture (either by extraction or vacuum distillation) and release of the formaldehyde by heating the hemiformal. The formaldehyde is then polymerized by anionic catalysis and the resulting polymer stabilized by reaction with acetic anhydride. A homopolymer is a polymer which is formed from only one type of monomer. ... As a general term, a substance is said to be anhydrous if it contains no water. ... A hemiacetal is a functional group or compound containing the function group in the form of: where R and R are any carbon backbones. ... In chemistry, liquid-liquid extraction (or more briefly, solvent extraction) is a useful method to separate components (compounds) of a mixture. ... This article or section does not cite its references or sources. ... An anion is an ion with negative charge. ... In chemistry and biology, catalysis is the acceleration (increase in rate) of a chemical reaction by means of a substance, called a catalyst, that is itself not consumed by the overall reaction. ... Acetic anhydride, also known as ethanoic anhydride, is one of the simplest of acid anhydrides. ...


To make polyoxymethylene copolymer, formaldehyde is generally converted to trioxane. This is done by acid catalysis (either sulfuric acid or acidic ion exchange resins) and concurrent removal of the trioxane by distillation or extraction. The trioxane is then dried to remove all water and other active hydrogen containing impurities. (Redirected from 1,3,5-trioxane) Trioxane or occasionally trioxymethylene (C3H6O3) is a cyclic trimer (a ring of three molecules) of formaldehyde. ... In acid catalysis and base catalysis a chemical reaction is catalized by an acid or a base. ... Sulfuric acid (British English: sulphuric acid), H2SO4, is a strong mineral acid. ... Ion exchange resin beads An ion exchange resin is an insoluble matrix (or support structure) normally in the form of small (1-2mm diameter) beads, usually white or yellowish, fabricated from an organic polymer substrate on the surface of which are sites with easily trapped and released ions in a...


The co-monomer is typically dioxolane but ethylene oxide can also be used. Dioxolane is formed by reaction of ethylene glycol with a formaldehyde source (trioxane or concentrated aqueous formaldehyde) over an acid catalyst. Other diols can also be used. A heteropolymer, also called a copolymer, is a polymer formed when two (or more) different types of monomer are linked in the same polymer chain, as opposed to a homopolymer where only one monomer is used. ... Dioxolane or 1,3-dioxolane is an heterocyclic acetal with the chemical formula C3H6O2. ... The chemical compound ethylene oxide is an important industrial chemical used as an intermediate in the production of ethylene glycol and other chemicals, and as a sterilant for foodstuffs and medical supplies. ... Ethylene glycol (monoethylene glycol (MEG), IUPAC name: ethane-1,2-diol) is an alcohol with two -OH groups (a diol), a chemical compound widely used as an automotive antifreeze. ...


Trioxane and Dioxolane are polymerized using an acid catalyst, often boron trifluoride etherate. The polymerization can take place in a non-polar solvent (in which case the polymer forms as a slurry) or in the melt (e.g. an extruder). After polymerization, the acidic catalyst must be deactivated and the polymer stabilized by heat. Boron trifluoride (BF3, trifluoroborane) is a pungent colourless toxic gas. ... Hydrophobe (from the Greek (hydros) water and (phobos) fear) in chemistry refers to the physical property of a molecule that is repelled by water. ... A solvent is a fluid phase (liquid, gas, or plasma) that dissolves a solid, liquid, or gaseous solute, resulting in a solution. ...


Stable polymer is melt compounded, adding thermal and oxidative stabilizers and optionally lubricants and miscellaneous fillers.


External links


  Results from FactBites:
 
POM, Acetal, Polyacetal, Polyoxymethylene - Kocetal by APIKOLON (658 words)
POM, Acetal, Polyacetal, Polyoxymethylene - Kocetal by APIKOLON
In the 1920s, a German chemist, Staudinger studied the polymerization and structure of Polyoxymethylene (POM) to research the theory of giant molecule.
However, due to lack of thermal stability, POM was not commercialized.
Nylon, Polyamide, Extruded Rods, Extruded Sheets, Polyacetal, Polyoxymethylene, Mumbai, India (455 words)
Nylon, Polyamide, Extruded Rods, Extruded Sheets, Polyacetal, Polyoxymethylene, Mumbai, India
Nylon 6 also known as Polyamide, is characterized by a combination of high strength, toughness and abrasion resistance and is ranked as an Engineering Plastic.
Polyacetal (Polyoxymethylene - POM) is a widely used crystalline engineering thermoplastic popularly known as Delrin® which is a homopolymer Polyacetal which exhibits slightly different characteristics in copolymer grades.
  More results at FactBites »

 
 

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