Synthetic polymers step-growth

Nylon (Section 21.9) A synthetic polyamide step-growth polymer. 

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... 

Once the potential associated with this aspect of molecular architecture is recognized, the principles of the last section coupled with the richness of organic (and inorganic) chemistry suggest numerous synthetic possibilities. We shall not attempt to be comprehensive in discussing this facet of polymer chemistry instead we cite only a few examples of step-growth polymers which incorporate... 

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-... 

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. 

Introduction to Synthetic Methods in Step-Growth Polymers... 

Synthetic Methods in Step-Growth Polymers. Edited by Martin E. Rogers and Timothy E. Long 2003 John Wiley Sons, Inc. ISBN 0-471-38769-X... 

INTRODUCTION TO SYNTHETIC METHODS IN STEP-GROWTH POLYMERS... 

Dendrimers produced by divergent or convergent methods are nearly perfectly branched with great structural precision. However, the multistep synthesis of dendrimers can be expensive and time consuming. The treelike structure of dendrimers can be approached through a one-step synthetic methodology.31 The step-growth polymerization of ABx-type monomers, particularly AB2, results in a randomly branched macromolecule referred to as hyperbranch polymers. 

J. L. Hedrick and J. W. Labadie, Step-Growth Polymers for High-Performance Materials New Synthetic Methods, ACS Symposium Series 624, American Chemical Society, Washington, DC, 1996. 

S. Cummings, E. Ginsburg, R. Miller, J. Portmess, D. W. Smith, Jr., andK. Wagener, in Step Growth Polymers for High Performance Materials New Synthetic Methods, J. L. Hedrick and J. W. Labadie (Eds.), ACS Symposium Series No. 624, American Chemical Society, Washington, DC, 1996, p. 113. 

Condensation polymers, which are also known as step growth polymers, are historically the oldest class of common synthetic polymers. Although superseded in terms of gross output by addition polymers, condensation polymers are still commonly used in a wide variety of applications examples include polyamides (nylons), polycarbonates, polyurethanes, and epoxy adhesives. Figure 1.9 outlines the basic reaction scheme for condensation polymerization. One or more different monomers can be incorporated into a condensation polymer. 

The step-growth polymerization of ABx-monomers is by far the most intensively studied synthetic pathway to hyperbranched polymers. A number of AB2-monomers, suitable for step-growth polymerizations, are commercially available. This has, of course, initiated substantial activity in hyperbranched condensation polymers and a wide variety of examples have been reported in the literature [4],... 

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. 

Hu, Q.-S., Nontraditional Step-Growth Polymerization—Transition Metal Coupling, in Synthetic Methods in Step-Growth Polymers, M. Rogers and T. Long, eds., Wiley, New York, 2003. 

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