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International Journal of Polymer Science
Volume 2009 (2009), Article ID 893234, 10 pages
Review Article

Origins and Development of Initiation of Free Radical Polymerization Processes

Deutsches Kunststoff-Institut, Schlossgartenstr. 6, 64289 Darmstadt, Germany

Received 10 June 2009; Accepted 26 October 2009

Academic Editor: Jose Ramon Leiza

Copyright © 2009 Dietrich Braun. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


At present worldwide about 45% of the manufactured plastic materials and 40% of synthetic rubber are obtained by free radical polymerization processes. The first free radically synthesized polymers were produced between 1910 and 1930 by initiation with peroxy compounds. In the 1940s the polymerization by redox processes was found independently and simultaneously at IG Farben in Germany and ICI in Great Britain. In the 1950s the systematic investigation of azo compounds as free radical initiators followed. Compounds with labile C–C-bonds were investigated as initiators only in the period from the end of the 1960s until the early 1980s. At about the same time, iniferters with cleavable S–S-bonds were studied in detail. Both these initiator classes can be designated as predecessors for “living” or controlled free radical polymerizations with nitroxyl-mediated polymerizations, reversible addition fragmentation chain transfer processes (RAFT), and atom transfer radical polymerizations (ATRP).