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Polyphosphazene
Polyphosphazenes include a wide range of hybrid inorganic chemistry, inorganic-organic chemistry, organic polymers with a number of different polymer architecture, skeletal architectures with the backbone phosphorus, P-nitrogen, N-P-N-P-N-. In nearly all of these materials two organic side groups are attached to each phosphorus center. Linear polymers have the formula (N=PR1R2)n, where R1 and R2 are organic (see graphic). Other architectures are cyclolinear and cyclomatrix polymers in which small phosphazene, phosphazene rings are connected together by organic chain units. Other architectures are available, such as block copolymer, polymer architecture, star, dendritic polymer, dendritic, or polymer architecture, comb-type structures. More than 700 different polyphosphazenes are known, with different side groups (R) and different molecular architectures. Many of these polymers were first synthesized and studied in the research group of Harry R. Allcock. __TOC__ Synthesis The method ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Hexachlorocyclotriphosphazene
Hexachlorophosphazene is an inorganic compound with the chemical formula . The molecule has a cyclic, unsaturated backbone consisting of alternating phosphorus and nitrogen atoms, and can be viewed as a trimer of the hypothetical compound (phosphazyl dichloride). Its classification as a phosphazene highlights its relationship to benzene. There is large academic interest in the compound relating to the phosphorus-nitrogen bonding and phosphorus reactivity. Occasionally, commercial or suggested practical applications have been reported, too, utilising hexachlorophosphazene as a precursor chemical.Mark, J. E.; Allcock, H. R.; West, R. “Inorganic Polymers” Prentice Hall, Englewood, NJ: 1992. . Derivatives of noted interest include the hexalkoxyphosphazene lubricants obtained from nucleophilic substitution of hexachlorophosphazene with alkoxides, or chemically resistant inorganic polymers with desirable thermal and mechanical properties known as polyphosphazenes produced from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Poly(dichlorophosphazene)
Poly(dichlorophosphazene), also called dichlorophosphazine polymer or phosphonitrilechloride polymer, is a chemical compound with formula (PNCl2)''n''. It is an inorganic (hence carbon-free) chloropolymer, whose backbone is a chain of alternating phosphorus and nitrogen atoms, connected by alternating single and double covalent bonds. The compound can be prepared by polymerization of hexachlorophosphazene ((PNCl2)3) by heating to ca. 250 °C.Hans Rytger Kricheldorf (1991), ''Handbook of Polymer Synthesis''Mario Gleria, Roger De Jaeger (2004) ''Phosphazenes: A Worldwide Insight''Nova Publishers, 2004. 1047 pages. , 9781590334232 It is an "inorganic rubber" and the starting material for many other polymers with the -P=N- backbone (polyphosphazenes), which have important commercial uses. History Poly(dichlorophosphazene) was discovered by H. N. Stokes in the 19th century, and at that time its superior properties over natural rubber were already noted.H. N. Stokes (1895)''On ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Phosphorus
Phosphorus is a chemical element; it has Chemical symbol, symbol P and atomic number 15. All elemental forms of phosphorus are highly Reactivity (chemistry), reactive and are therefore never found in nature. They can nevertheless be prepared artificially, the two most common allotropes being white phosphorus and red phosphorus. With as its only stable isotope, phosphorus has an occurrence in Earth's crust of about 0.1%, generally as phosphate rock. A member of the pnictogen family, phosphorus readily forms a wide variety of organic compound, organic and inorganic compound, inorganic compounds, with as its main oxidation states +5, +3 and −3. The isolation of white phosphorus in 1669 by Hennig Brand marked the scientific community's first discovery since Antiquity of an element. The name phosphorus is a reference to the Phosphorus (morning star), god of the Morning star in Greek mythology, inspired by the faint glow of white phosphorus when exposed to oxygen. This property is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Organometallic
Organometallic chemistry is the study of organometallic compounds, chemical compounds containing at least one chemical bond between a carbon atom of an organic molecule and a metal, including alkali, alkaline earth, and transition metals, and sometimes broadened to include metalloids like boron, silicon, and selenium, as well. Aside from bonds to organyl fragments or molecules, bonds to 'inorganic' carbon, like carbon monoxide (Metal carbonyl, metal carbonyls), cyanide, or carbide, are generally considered to be organometallic as well. Some related compounds such as transition metal hydrides and metal phosphine complexes are often included in discussions of organometallic compounds, though strictly speaking, they are not necessarily organometallic. The related but distinct term "metalorganics, metalorganic compound" refers to metal-containing compounds lacking direct metal-carbon bonds but which contain organic ligands. Metal β-diketonates, alkoxides, dialkylamides, and metal p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Radical Polymerization
In polymer chemistry, radical polymerization (RP) is a method of polymerization by which a polymer forms by the successive addition of a radical to building blocks ( repeat units). Radicals can be formed by a number of different mechanisms, usually involving separate initiator molecules. Following its generation, the initiating radical adds (nonradical) monomer units, thereby growing the polymer chain. Radical polymerization is a key synthesis route for obtaining a wide variety of different polymers and materials composites. The relatively non-specific nature of radical chemical interactions makes this one of the most versatile forms of polymerization available and allows facile reactions of polymeric radical chain ends and other chemicals or substrates. In 2001, 40 billion of the 110 billion pounds of polymers produced in the United States were produced by radical polymerization. Radical polymerization is a type of chain polymerization, along with anionic, cationic and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Polymerization
In polymer chemistry, polymerization (American English), or polymerisation (British English), is a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks. There are many forms of polymerization and different systems exist to categorize them. In chemical compounds, polymerization can occur via a variety of reaction mechanisms that vary in complexity due to the functional groups present in the reactants and their inherent steric effects. In more straightforward polymerizations, alkenes form polymers through relatively simple radical reactions; in contrast, reactions involving substitution at a carbonyl group require more complex synthesis due to the way in which reactants polymerize. As alkenes can polymerize in somewhat straightforward radical reactions, they form useful compounds such as polyethylene and polyvinyl chloride (PVC), which are produced in high tonnages each year due to their usefulnes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Substituent
In organic chemistry, a substituent is one or a group of atoms that replaces (one or more) atoms, thereby becoming a moiety in the resultant (new) molecule. The suffix ''-yl'' is used when naming organic compounds that contain a single bond replacing one hydrogen; ''-ylidene'' and ''-ylidyne'' are used with double bonds and triple bonds, respectively. In addition, when naming hydrocarbons that contain a substituent, positional numbers are used to indicate which carbon atom the substituent attaches to when such information is needed to distinguish between isomers. Substituents can be a combination of the inductive effect and the mesomeric effect. Such effects are also described as electron-rich and electron withdrawing. Additional steric effects result from the volume occupied by a substituent. The phrases ''most-substituted'' and ''least-substituted'' are frequently used to describe or compare molecules that are products of a chemical reaction. In this terminology, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Vinyl Group
In organic chemistry, a vinyl group (abbr. Vi; IUPAC name: ethenyl group) is a functional group with the formula . It is the ethylene (IUPAC name: ethene) molecule () with one fewer hydrogen atom. The name is also used for any compound containing that group, namely where R is any other group of atoms. An industrially important example is vinyl chloride, precursor to PVC, a plastic commonly known as ''vinyl''. Vinyl is one of the alkenyl functional groups. On a carbon skeleton, sp2-hybridized carbons or positions are often called vinylic. Allyls, acrylates and styrenics contain vinyl groups. (A styrenic crosslinker with two vinyl groups is called '' divinyl benzene''.) Vinyl polymers Vinyl groups can polymerize with the aid of a radical initiator or a catalyst, forming vinyl polymers. Vinyl polymers contain no vinyl groups. Instead they are saturated. The following table gives some examples of vinyl polymers. Synthesis and reactivity Vinyl derivatives are alke ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Allyl
In organic chemistry, an allyl group is a substituent with the structural formula . It consists of a methylene bridge () attached to a vinyl group (). The name is derived from the scientific name for garlic, . In 1844, Theodor Wertheim isolated an allyl derivative from garlic oil and named it "". The term allyl applies to many compounds related to , some of which are of practical or of everyday importance, for example, allyl chloride. Allylation is any chemical reaction that adds an allyl group to a Substrate (chemistry), substrate. Nomenclature A site adjacent to the unsaturated carbon atom is called the allylic position or allylic site. A group attached at this site is sometimes described as allylic. Thus, "has an allylic hydroxyl group". Allylic Carbon–hydrogen bond, C−H bonds are about 15% weaker than the C−H bonds in ordinary Orbital hybridisation, sp3 carbon centers and are thus more reactive. Benzylic and allylic are related in terms of structure, bond strength ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Living Cationic Polymerization
Living or The Living may refer to: Common meanings *Life, a condition that distinguishes organisms from inorganic objects and dead organisms ** Living species, one that is not extinct *Personal life, the course of an individual human's life * Living (Christianity) or benefice, in canon law, a position in a church that has attached to it a source of income Music * ''Living'' (Paddy Casey album) or the title song, "Livin, 2003 * ''Living'' (Judy Collins album), 1971 *''Living 2001–2002'', an album by the John Butler Trio, 2003 * ''Living'' (EP) or the title song, by Josephine Collective, 2007 * "Living" (song), by Dierks Bentley, 2019 * The Living, early 1980's Seattle punk rock band featuring Duff McKagan Television and film * ''Living'' (1954 TV program), a 1954–1955 Canadian informational program * ''Living'' (2007 TV program), a 2007–2009 group of regional Canadian lifestyle programs * Living (New Zealand TV channel), a New Zealand television station * Living ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
