Anionic addition polymerization: Difference between revisions

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'''Anionic addition polymerization''' is a form of [[chain-growth polymerization]] or addition polymerization that involves the [[polymerization]] of monomers initiated with anions. The type of reaction has many manifestations, but traditionally vinyl monomers are used.<ref name=Hsieh>Hsieh, H.;Quirk, R. ''Anionic Polymerization: Principles and practical applications''; Marcel Dekker, Inc.: New York, 1996.</ref><ref name=Quirk>Quirk, R. Anionic Polymerization. In ''Encyclopedia of Polymer Science and Technology''; John Wiley and Sons: New York, 2003.</ref> Often anionic polymerization involves [[living polymerization]]s, which allows control of structure and composition.<ref name="Hsieh"/><ref name="Quirk"/>

== History ==

[[File:ET-coupledStyrene.png|thumb|Product of the reductive coupling of styrene with lithium, 1,4-dilithio-1,4-diphenylbutane. In the original work, Szwarc studied the analogous disodium compound.<ref>{{cite book|chapter=Ionic Polymerization|author=Sebastian Koltzenburg, |author2=Michael Maskos, |author3=Oskar Nuyken|title=Polymer Chemistry|isbn=978-3-662-49279-6|publisher=Springer|date=2017-12-11}}</ref>]]

As early as 1936, [[Karl Ziegler]] proposed that anionic polymerization of styrene and butadiene by consecutive addition of monomer to an alkyl lithium initiator occurred without chain transfer or termination. Twenty years later, living polymerization was demonstrated by Szwarc and coworkers.<ref>{{cite journal|title=Polymerization Initiated by Electron Transfer to Monomer. A New Method of Formation of Block Polymers|first1=M.|last1=Szwarc|first2=M.|last2= Levy|first3=R.|last3=Milkovich|journal=J. Am. Chem. Soc.|year=1956|volume=78|issue=11|page=2656–2657

|doi=10.1021/ja01592a101}}</ref><ref>{{cite journal|author=M. Szwarc |year=1956|title="Living" polymers|journal=Nature|volume=178|issue=4543|page=1168|doi=10.1038/1781168a0|bibcode=1956Natur.178.1168S}}</ref> In one of the breakthrough events in the field of [[polymer science]], Szwarc elucidated that [[electron transfer]] occurred from [[radical anion]] of [[naphthalene]] to [[styrene]]. The results in the formation of a [[dianion]] (or equivalently disodio-) species, which rapidly added styrene to form a "two – ended living polymer." An important aspect of his work, Szwarc employed the [[aprotic solvent]] [[tetrahydrofuran]]. Being a [[physical chemist]], Szwarc elucidated the [[chemical kinetics|kinetics]] and the [[thermodynamics]] of the process in considerable detail. At the same time, he explored the structure property relationship of the various [[ion pair]]s and radical ions involved. This work provided the foundations for the rational synthesis of polymers with control over [[molecular weight]], molecular weight distribution, and the architecture of the polymer.<ref>Smid, J. Historical Perspectives on Living Anionic Polymerization. ''J. Polym. Sci. Part A.''; '''2002''', ''40'',pp. 2101-2107. [https://archive.today/20121012113202/http://www3.interscience.wiley.com/journal/94515609/abstract DOI=10.1002/pola.10286]</ref>

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===Block copolymers===

Synthesis of block copolymers is one of the most important applications of living polymerization as it offers the best control over structure. The [[nucleophilicity]] of the resulting carbanion will govern the order of monomer addition, as the monomer forming the less nucleophilic propagating species may inhibit the addition of the more nucleophilic monomer onto the chain. An extension of the above concept is the formation of triblock copolymers where each step of such a sequence aims to prepare a block segment with predictable, known molecular weight and narrow molecular weight distribution without chain termination or transfer.<ref>Hsieh, H.;Quirk, R. Anionic Polymerization: Principles and practical applications; Marcel Dekker, Inc.: New York, 1996.</ref>

Sequential monomer addition is the dominant method, also this simple approach suffers some limitations.</ref>

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==Additional reading==

*Cowie, J.; Arrighi,V. ''Polymers: Chemistry and Physics of Modern Materials''; CRC Press: Boca Raton, FL, 2008.

*{{cite journal|author=Hadjichristidis, N.; |author2=Iatrou, H.; |author3=Pitsikalis, P.; |author4=Mays, J.|title=Macromolecular architectures by living and controlled/living polymerizations|journal=Prog. Polym. Sci.|year=2006|volume=31|issue=12|page=1068–1132|doi=10.1016/j.progpolymsci.2006.07.002}}

*{{cite journal|author=Efstratiadis, V.; |author2=Tselikas, Y.; |author3=Hadjichristidis, N.; |author4=Li, J.; |author5=Yunan, W.; |author6=Mays, J.|title=Synthesis and characterization of poly(methyl methacrylate) star polymers|journal=Polym Int.|year=1994|volume=4|issue=2|page=171–179|doi=10.1002/pi.1994.210330208}}

*{{cite book|author=Rempp, P.; |author2=Franta, E.; |author3=Herz, J.|s2cid=92176703|title=Polysiloxane Copolymers/Anionic Polymerization|chapter=Macromolecular Engineering by Anionic Methods|year=1998|volume=4|page= 145–173|doi=10.1007/BFb0025276|series=Advances in Polymer Science|isbn=978-3-540-18506-2}}

*{{cite journal|title=Universal Methodology for Block Copolymer Synthesis|first1=Vasilios|last1=Bellas|first2=Matthias|last2=Rehahn|s2cid=96556942|date=2 July 2007|journal=Macromolecular Rapid Communications|volume=28|issue=13|page=1415–1421|doi=10.1002/marc.200700127}}

*{{cite book|title=Anionic Polymerization Principles, Practice, Strength, Consequences and Applications|editor=Nikos Hadjichristidis, |editor2=Akira Hirao|year=2015|isbn=978-4-431-54186-8|publisher=Springer}}

==References==

{{reflistReflist}}

{{DEFAULTSORT:Anionic Addition Polymerization}}