Symposium on Ionic Polymerization (IP99)
1923 July 1999
symposium, held in the Kyoto International Conference Hall, was sponsored
by the Chemical Society of Japan, the Society of Polymer Science of
Japan, the Society of Synthetic Organic Chemistry of Japan, and the
Japan Chemical Innovation Institute, in addition to IUPAC.
Prof. Shohei Inoue (Science University, Tokyo)
was the Honorary Chairman of the symposium. Prof. Shiro Kobayashi
(Kyoto University) chaired the Organizing Committee, Prof. Mitsuo
Sawamoto (Kyoto University) headed the Program Committee, and Prof.
Yoshiki Chujo was Chairman of the Local Committee. The International
Symposia on Ionic Polymerization have a long history. They were started
in the late 1940s and early 1950s by Prof. David Pepper (Dublin, Ireland)
and Prof. Peter Plesch (Keele, United Kingdom), who at that time dominated
the field of cationic polymerization. Then, after the discovery of
the processes of "living polymerization" by Prof. Michael
Szwarc, founder and "father" of modern ionic polymerization,
a series of more or less formal meetings was organized in the field
of anionic polymerization.
Two decades later (in 1975), I organized the first
IUPAC Symposium on Ring-Opening Polymerization. Finally, the concerted
efforts of a group of scientists working on anionic, cationic, and
ring-opening polymerization converted these separate meetings into
a chain of symposia unifying all of the fields of ionic polymerization.
The Kyoto Symposium was the third one (after Istanbul and Paris) of
this new series. In attendance were more than 260 active participants,
including an impressive number of younger Japanese scientists who
presented high-quality lectures on the newest topics. In all, 34 invited
lectures, 60 other lectures, and 61 posters were presented. Practically
all of the important research centers in the field of ionic polymerization
from all over the world were represented at this impressive meeting.
Lectures comparing radical and ionic polymerizations (K. Matyjaszewski)
and/or enzymatic processes (S. Kobayashi) were presented, as well
as other lectures on radical processes that kinetically resemble living
ionic polymerization (e.g., papers by A. Matsumoto, K. Muellen, Y.
Okamoto, and others). Polymerization mechanisms, macromolecular syntheses,
and properties of polymers prepared by ionic and radical polymerization
were also presented.
Several presentations particularly sparked my
imagination, although such a selection is invariably subjective. The
work of a group of authors (Percec, Barboiu, Bera, Kim, Frechet, and
Grubbs) whose efforts, described by Percec, were related to the synthesis
of single macromolecules of highly sophisticated, complex architecture
was achieved by polymerization of well-defined dendrimers. The lecture
by Matyjaszewski (mentioned above) showed how to combine ionic and
radical processes in the synthesis of block copolymers of well-defined
structures. Rizzardo presented an important step forward in synthesis
of macromolecules with well-defined backbones by using a novel effective
chain transfer. The ingenious choice of the chain transfer agents
in radical polymerization allowed preparation of a number of vinyl
polymers with controlled molar masses, molar mass distribution, and
end-groups. Finally, Sawamoto presented his own approach to radical
polymerization mediated by transition metals. It is difficult and
probably impossible to predict which of the many novel radical processes
will finally emerge to be become practical and routine.
Of course, understanding of the kinetic features
of the processes presented would not be possible without the accumulated
knowledge from living anionic polymerization and other (e.g., ring-opening)
processes where the temporarily deactivated (dormant) species coexist
with instantaneously active ones in the same macromolecule over various
periods of time. In already well-established areas of anionic polymerization,
several speakers (Moreau, Vairon, and others) presented striking new
achievements, such as copolymerization of two aldehydes to give a
much lower equilibrium monomer concentration for both comonomers than
in their respective homopolymerizations. This result could be expected
but it was shown for the first time in the polymerization of aldehydes,
and it opened up new, interesting synthetic possibilities for this
vast class of monomers.
Several impressive lectures were given by seasoned
scientists (Fontanille, Sigwalt, Goethals, Mueller, Higashimura, Deffieux,
Zsuga, Charadame, Faust, Aida, Kubisa, Duda, and some others), all
of whom have already been contributing to their fields for several
decades. However, a group of excellent younger scientists (R. Gross,
Y. Chujo, and others) appeared, bringing their own views to this well-explored
field. Some participants took the opportunity to visit the Kansai
Research Institute, Inc., located in Kyoto Research Park, where a
large proportion of scientific activity is related to macromolecular
chemistry and physics. Prof. Takeo Shimidzu, Executive Vice President
of this Institute, was kind enough to describe personally the major
areas of research for the IP99 Symposium visitors. An interesting
social program was also planned and carried out by the charming Miyo
Kobayashi, wife of the symposium chairman.