Anionic addition polymerization: Difference between revisions

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== History ==

[[File:ET-coupledStyrene.png|thumb|Product of the reductive coupling of styrene, 1,4-dilithio-1,4-diphenylbutane.<ref>{{cite book|chapter=Ionic Polymerization|author=Sebastian Koltzenburg, Michael Maskos, Oskar Nuyken|title=Polymer Chemistry|isbn=978-3-662-49279-6|publisher=Springer}}</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.<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|page=2656-2657
|doi=10.1021/ja01592a101}}</ref><ref>{{cite journal|author=M. Szwarc |year=1956|title="Living" polymers|journal=Nature|volume=178|page=1168|doi=10.1038/1781168a0}}</ref> The early work of [[Michael Szwarc]] and co – workers in 1956 was In one of the breakthrough events in the field of [[polymer science]], Szwarc learned that the [[electron transfer]] between [[radical anion]] of [[naphthalene]] and [[styrene]] in an [[aprotic solvent]] such as [[tetrahydrofuran]] results in the formation of a [[dianion]], which rapidly added styrene to form a "two – ended living polymer." 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>

The use of [[alkali metals]] to initiate polymerization of 1,3-[[diene]]s led to the discovery by Stavely and co-workers at Firestone Tire and Rubber company of cis-1,4-[[polyisoprene]].<ref name=Odian>Odian, G. Ionic Chain Polymerization; In '' Principles of Polymerization''; Wiley-Interscience: Staten Island, New York, 2004, pp. 372-463.</ref> This sparked the development of commercial anionic polymerization processes that utilize alkyllithium initiatiors.<ref name="Quirk"/>

Living polymerization was demonstrated by Szwarc and co workers in 1956. Their initial work was based on the polymerization of styrene and dienes.

== Monomer characteristics ==