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Macromolecular Division (IV)


Number: 2002-006-2-400

Title: Terminology for radical polymerizations with minimal termination - the so-called "living" and/or "controlled" radical polymerization

Task Group
Aubrey D. Jenkins

Members: Takeshi Fukuda, Robert G. Gilbert, Michael Hess, Richard G. Jones, Pavel Kratochvíl, Krystof Matyjaszewski, Graeme Moad, Kohji Ohno, Stanislaw Penczek, Gregory Russell, Robert Stepto, Jean-Pierre Vairon, and Jiri Vohlidal

To provide recommendations for nomenclature and terminology in relation to modern (1994-) techniques of radical polymerisation, variously described in the literature as, e.g., "living" and/or "controlled".

There has been an explosion of renewed interest in radical polymerisation during the last nine to ten years, stemming largely from the discovery of new polymerization techniques which provide products with novel molecular architecture, composition, and molar-mass distribution. This burst of activity has given rise to a diverse and uncoordinated terminology. The use of inappropriate terms, and the lack of uniformity of practice, constitute severe impediments to intelligible communication and effective literature-searching, with consequent potential to retard the development of this important field.

A few recent publications have addressed some aspects of the problem and provided suggestions for possible terminology. These include the following:

Matyjaszewski, K. and Mueller, A. H. E., "Macromolecular nomenclature note No. 12. Naming of controlled, living and "living" polymerizations", Polym. Prepr., 38(1), 6-9 (1997).

Darling, T. R., Davis, T. P., Fryd, M., Gridnev, A. A., Haddleton, D. M., Ittel, S. D., Matheson, R. R., Jr., Moad, G. and Rizzardo, E., "Living polymerization: rationale for uniform terminology", J. Polym. Sci., Part A: Polym. Chem., 38, 1706-1708 (2000), (and subsequent papers in this issue).

Ivan, B., "Macromolecular nomenclature note No. 19. Terminology and classification of quasiliving polymerizations and ideal living polymerizations on the basis of the logic of elementary polymerization reactions, and comments on using the term "controlled", Polym. Prepr. 41(2), 6a-12a (2000).

Howell, B. A., "Mediated radical polymerization", Polym. Mater. Sci. Eng., 83, 578 (2000).

Fischer, H., "The Persistent Radical Effect", Chem. Rev.,101, 3581 (2001).

These papers display a diversity of views: none of the terminologies advocated has achieved widespread acceptance, neither has any of them been adopted as IUPAC-recommended terminology. Moreover, there are additional issues to be addressed relating to the misapplication of classical terminology to new circumstances.

The frenzy of activity on the part of individuals outside IUPAC to attempt to define terms, or calling for regulated terminology, demonstrates the urgent need for an appropriate IUPAC body to take speedy action to provide an internationally-agreed set of terms in this field. It also shows that there is no need for a preliminary feasibility study, which would only waste time and allow the situation to deteriorate further.

An existing IUPAC project #2002-016-1-400 titled "Terminology for the kinetics, thermodynamics, and mechanism of polymerization" has touched on some of the issues proposed to be addressed by this new working party but with much broader terms of reference. Nonetheless, the report from this project (expected during the next few months) will have significant value in relation to the project outlined here.

The initial step will be to compile, and critically evaluate, the existing terminology. There will be a need to coordinate with, and perhaps suggest modification of, some aspects of the terminology of conventional radical polymerisation and other forms of polymerization (e.g., anionic, cationic, so-called group-transfer, coordination, ring-opening, metathesis). However, the initial focus will be directed to the area of radical polymerisation.

Most of the interaction among TaskGroup Members will take the form of correspondence by e-mail; face-to-face meetings/workshops will be coordinated with IUPAC General Assemblies or international meetings in the field of polymerisation.

Pending further discussion, the tentative title "New Radical Polymerization" (NRP) has been given to this project, with the intention of devising a more satisfactory name in the course of the work.
An initial scrutiny of the terminology in common use revealed that the term "living" is contentious, and this fact has impeded progress because it would be a most valuable term to employ, if only it could be defined in such a way that everyone could agree on its significance. In the immediate future, the prospect of achieving this desirable end seems to be bleak. Nevertheless, considerable progress has been made. An important feature of this project is its relationship to project 2002-016-1-400, led by Professor Stanislaw Penczek, on the Glossary of Terms Related to Kinetics, Thermodynamics and Mechanisms of Polymerization; several of the terms included in the document emerging from the latter project will be vital for NRP. Thus, to some extent, these two projects have been running in tandem, and valuable developments have been made, particularly the definition of terms relating to termination, deactivation, and reactivation in radical polymerization. It is to be hoped that this work will be endorsed at the General Assembly in 2005, in which case the development of terminology for NRP should be able to advance more rapidly.

The task group met at the General Assembly in Ottawa, 2003, and in Bordeaux in 2004; between meetings, much correspondence has taken place by e-mail. It will discuss substantial proposals for progress at the General Assmbly in 2005; if these are accepted, it may be possible to complete the project, and produce a draft document, in 2006.

April 2008 - A draft titled 'Terminology for radical polymerizations with minimal termination - the so-called 'living' and/or 'controlled' radical polymerization' is submitted to public review comments until 30 September 2008 > see provisional recommendations

Last update: 29 April 2008

<project announcement published in Chem. Int. July 2003 >

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