Synthetic polymers chain-growth

There are two main classes of synthetic polymers chain-growth polymers and step-growth polymers. Polyethylene and other alkene and diene polymers like those we saw in Sections 8.10 and 14.6 are chain-growth polymers because... 

Synthetic polymers can be classified as either chain-growth polymen or step-growth polymers. Chain-growth polymers are prepared by chain-reaction polymerization of vinyl monomers in the presence of a radical, an anion, or a cation initiator. Radical polymerization is sometimes used, but alkenes such as 2-methylpropene that have electron-donating substituents on the double bond polymerize easily by a cationic route through carbocation intermediates. Similarly, monomers such as methyl -cyanoacrylate that have electron-withdrawing substituents on the double bond polymerize by an anionic, conjugate addition pathway. 

Synthetic polymers can be classified as either chain-growth polymers or step-growth polymers. Chain-growth polymers are prepared by chain-atactic, 1267 reaction polymerization of vinyl monomers in the presence of a radical, an... 

The large number of reported studies indicates that mass spectrometry is growing in importance as a valuable technique for the analysis and characterization of synthetic polymers. While publications relating to synthetic polymer/ copolymer characterization seem to favor MALDI over other mass spectrometry methods, ESI is also used consistently, in numerous studies, to follow polymer reaction kinetics and to study polymer chain growth on active catalyst substrates. 

Synthetic polymers are classified by their method of synthesis as either chain-growth or step-growth. The categories ate somewhat imprecise but nevertheless provide a useful distinction. Chain-growth polymers are produced by chain-reaction polymerization in which an initiator adds to a carbon-carbon double bond of an unsaturated substrate (a vinyl monomer) to yield a reactive inter-... 

There are two main chemical mechanisms by which a synthetic polymer may be produced namely by either a condensation (step growth) polymerisation or addition (chain) polymerisation. 

Nearly all synthetic polymers are synthesized by the polymerization or copolymerization of different "monomers." The chain growth process may involve the addition chain reactions of unsaturated small molecules, condensation reactions, or ringopening chain-coupling processes. In conventional polymer chemistry, the synthesis of a new polymer requires the use of a new monomer. This approach is often unsatisfactory for Inorganic systems, where relatively few monomers or cyclic oligomers can be Induced to polymerize, at least under conditions that have been studied to date. The main exception to this rule is the condensation-type growth that occurs with inorganic dl-hydroxy acids. 

The formation of synthetic polymers is a process which occurs via chemical connection of many hundreds up to many thousands of monomer molecules. As a result, macromolecular chains are formed. They are, in general, linear, but can be branched, hyperbranched, or crosslinked as well. However, depending on the number of different monomers and how they are connected, homo- or one of the various kinds of copolymers can result. The chemical process of chain formation may be subdivided roughly into two classes, depending on whether it proceeds as a chain-growth or as a step-growth reaction. 

There are, however, synthetic constraints on the use of anhydro sugars as a source of polysaccharides, because chain-growth processes generally lead to the formation of homopolymers only, or, if two or more monomers are used, to the formation of random copolymers. In these processes, the polymer composition and mer sequence-... 

Few chain growth polymers with metal-metal bonds have been reported. The general synthetic route to these materials is to substitute a ligand on a metal-metal bonded dimer with a polymerizable olefin. In the case of Cp2M2(CO)ra-type molecules (M = Mo, W, Fe), it is difficult to synthesize a dimer that has only one substituted Cp ring, and hence both Cp rings are substituted with polymerizable olefins. This leads to cross-linked polymers with metal-metal bonds in the chain. Examples of this reactivity are shown in Scheme 4.43... 

McMillan, E M. 1979. The chain straighteners. Fruitful innovation The discovery of linear and stereoregular synthetic polymers. London Macmillan Press. Morawetz, M. 1985. Polymers The origins and growth of a science. New York, NY "Wiley Intersdence. 

What Is a Polymer, Anyway Call in the Special Forces Hermann Staudinger and Herman Mark Who s the Fatherf Wallace Carothers and the First Synthetic Fiber From Globs to Fiber Chain-Growth Polymers... 

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