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Atom transfer radical polymerization (ATRP) is an example of a reversible-deactivation radical polymerization. Like its counterpart, ATRA or atom transfer radical addition, it is a means of forming a carbon-carbon bond through a transition metal catalyst. As the name implies, the atom transfer step is the key step in the reaction responsible for uniform polymer chain growth. ATRP (or transition metal-mediated living radical polymerization) was independently discovered by Mitsuo Sawamoto and by Krzysztof Matyjaszewski in 1995.〔(【引用サイトリンク】title=The 2011 Wolf Prize in Chemistry )〕 ::The following scheme presents a typical ATRP reaction: ==Overview of ATRP== ATRP usually employs a transition metal complex as the catalyst with an alkyl halide as the initiator (R-X). Various transition metal complexes, namely those of Cu, Fe, Ru, Ni, Os, etc., have been employed as catalysts for ATRP. In an ATRP process, the dormant species is activated by the transition metal complex to generate radicals via one electron transfer process. Simultaneously the transition metal is oxidized to higher oxidation state. This reversible process rapidly establishes an equilibrium that is predominately shifted to the side with very low radical concentrations. The number of polymer chains is determined by the number of initiators. Each growing chain has the same probability to propagate with monomers to form living/dormant polymer chains (R-Pn-X). As a result, polymers with similar molecular weights and narrow molecular weight distribution can be prepared. ATRP reactions are very robust in that they are tolerant of many functional groups like allyl, amino, epoxy, hydroxy and vinyl groups present in either the monomer or the initiator.〔Cowie, J. M. G.; Arrighi, V. In Polymers: Chemistry and Physics of Modern Materials; CRC Press Taylor and Francis Group: Boca Raton, Fl, 2008; 3rd Ed., pp. 82–84 ISBN 0849398134 〕 ATRP methods are also advantageous due to the ease of preparation, commercially available and inexpensive catalysts (copper complexes), pyridine based ligands and initiators (alkyl halides).〔Matyjaszewski, K. (Fundamentals of ATRP Research ) (accessed 01/07, 2009).〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Atom-transfer radical-polymerization」の詳細全文を読む スポンサード リンク
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