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Chain Initiation
Chain-growth polymerization ( AE) or chain-growth polymerisation ( BE) is a polymerization technique where unsaturated monomer molecules add onto the active site on a growing polymer chain one at a time. There are a limited number of these active sites at any moment during the polymerization which gives this method its key characteristics. Introduction In 1953, Paul Flory first classified polymerization as " step-growth polymerization" and "chain-growth polymerization". IUPAC recommends to further simplify "chain-growth polymerization" to "chain polymerization". It is a kind of polymerization where an active center (free radical or ion) is formed, and a plurality of monomers can be polymerized together in a short period of time to form a macromolecule having a large molecular weight. In addition to the regenerated active sites of each monomer unit, polymer growth will only occur at one (or possibly more) endpoint. Many common polymers can be obtained by chain polymerization ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American English
American English, sometimes called United States English or U.S. English, is the set of variety (linguistics), varieties of the English language native to the United States. English is the Languages of the United States, most widely spoken language in the United States and in most circumstances is the de facto common language used in government, education and commerce. Since the 20th century, American English has become the most influential form of English worldwide. American English varieties include many patterns of pronunciation, vocabulary, grammar and particularly spelling that are unified nationwide but distinct from other English dialects around the world. Any North American English, American or Canadian accent (sociolinguistics), accent perceived as lacking noticeably local, ethnic or cultural markedness, markers is popularly called General American, "General" or "Standard" American, a fairly uniform dialect continuum, accent continuum native to certain regions of the U ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
