How to use polymethylene in a sentence? Find typical usage patterns (collocations)/phrases/context for "polymethylene" and check conjugation/comparative form for "polymethylene". Mastering all the usages of "polymethylene" from sentence examples published by news publications.
The tropocoronand ligand (H2TC-m,n) is a macrocyclic ligand in which two aminotroponiminate rings are connected to one another via polymethylene linker chains of length m and n. Double deprotonation of the ligand yields a dianionic macrocylic species that is capable of binding divalent transition metal ions to form neutral complexes [M(TC-m,n)]. The 2-aminotroponeimine units are bridged by polymethylene linker chains with all four nitrogen atoms of the tropocoronand ligand bonded to a metal atom.Seichi Imajo and Koji Nakanishi.
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The folk remedy French lilac (Galega officinalis), was used to treat the symptoms of diabetes, and towards the end of the nineteenth century it was discovered to contain guanidine. This had a hypoglycaemic effect but was very toxic to the liver. Karl Slotta at the Chemistry Institute of the University of Vienna synthesized derived compounds that had a polymethylene chain with a guanidine group at each end. These diguanides were less toxic and more potent than guanidine.
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Idealized EPDM polymer, red = ethylene-derived, blue = propylene-derived, black = ethylidene norbornene-derived. EPDM rubber (ethylene propylene diene monomer rubber) is a type of synthetic rubber that is used in many applications. EPDM is an M-Class rubber under ASTM standard D-1418; the M class comprises elastomers having a saturated chain of the polyethylene type (the M deriving from the more correct term polymethylene). EPDM is made from ethylene, propylene, and a diene comonomer that enables crosslinking via Sulfur vulcanization.
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The average end-to-end distance for freely-rotating (not freely- jointed) polymethylene (polyethylene with each -C-C- considered as a subunit) is l times the square root of 2N, an increase by a factor of about 1.4. Unlike the zero volume assumed in a random walk calculation, all real polymers' segments occupy space because of the van der Waals radii of their atoms, including bulky substituent groups that interfere with bond rotations. This can also be taken into account in calculations. All such effects increase the mean end-to-end distance.
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In 1926, E. Frank, working in Oskar Minkowski's clinic in Wroclaw performed a clinical trial on one of these agents. It was subsequently marketed as Synthalin by Schering AG for treating mild cases of diabetes. Adverse reports on the toxicity of Synthalin prompted the development of Synthalin B (which had a slightly longer polymethylene chain and was claimed to be safer) and the former product was re-branded Synthalin A. However liver toxicity continued to be a problem, leading to discontinuation in the 1930s, though Synthalin B continued to be used in Germany until the mid-1940s.
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At room temperature, hexamethyltungsten decomposes, releasing methane and trace amounts of ethane. The black residue is purported to contain polymethylene and tungsten, but the decomposition of W(CH3)6 to form tungsten metal is highly unlikely. The following equation is the approximate stoichiometry proposed by Wilkinson and Shortland: : → 3 + + W Like many organometallic complexes, WMe6 is destroyed by oxygen. Similarly, acids give methane and unidentified tungsten derivatives, while halogens give the methyl halide and leave the tungsten halide. A patent application was submitted in 1991 suggesting the use of W(CH3)6 in the manufacture of semiconductor devices for chemical vapor deposition of tungsten thin films; however, to date it has not been used for this purpose.
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Polyethylene was first synthesized by the German chemist Hans von Pechmann, who prepared it by accident in 1898 while investigating diazomethane. When his colleagues Eugen Bamberger and Friedrich Tschirner characterized the white, waxy substance that he had created, they recognized that it contained long -CH2- chains and termed it polymethylene. pill box presented to a technician at ICI in 1936 made from the first pound of polyethylene The first industrially practical polyethylene synthesis (diazomethane is a notoriously unstable substance that is generally avoided in industrial application) was again accidentally discovered in 1933 by Eric Fawcett and Reginald Gibson at the Imperial Chemical Industries (ICI) works in Northwich, England. Upon applying extremely high pressure (several hundred atmospheres) to a mixture of ethylene and benzaldehyde they again produced a white, waxy material.
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