Transition Metal Catalysis in Macromolecular Design

298 Pages·2000·3.2 MB·English

by  Lisa Saunders Boffa and Bruce M. Novak (Eds.)

Transition Metal Catalysis
1 in Macromolecular Design
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In Transition Metal Catalysis in Macromolecular Design; Boffa, L., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 2000.
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In Transition Metal Catalysis in Macromolecular Design; Boffa, L., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 2000.
ACS SYMPOSIUM SERIES 760
1
00 Transition Metal Catalysis
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07 in Macromolecular Design
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p://pgust Lisa Saunders Boffa, EDITOR
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August 27, Publication BrNuorcthe CMaro. liNnao Svtaatke ,U nEiDveIrTsiOty R

American Chemical Society, Washington, DC
In Transition Metal Catalysis in Macromolecular Design; Boffa, L., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 2000.
Library of Congress Cataloging-in-Publication Data
Transition metal catalysis in macromolecular design / Lisa Saunders Boffa, editor, Bruce M. Novak,
editor,
p. cm.—(ACS symposium series, ISSN 0097-6156 ; 760)
Includes bibliographical references and index.
1 ISBN 0-8412-3673-9
0
0
w
0.f 1. Polymerization—Congresses. 2. Transition metal catalysts—Congresses.
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7
0-0 I. Boffa, Lisa Saunders, 1969- . II. Novak, Bruce M., 1955- .III. Series.
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0
k-2 QD281..P6 T727 2000
1/b 547'.28—dc21 00-22803
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0.
1 The paper used in this publication meets the minimum requirements of American National Standard
oi: for Information Sciences—Permanence of Paper for Printed Library Materials, ANSI Z39.48-1984.
s.org 00 | d Copyright © 2000 American Chemical Society
c0
ubs.a10, 2 Distributed by Oxford University Press
http://pAugust All Rights Reserved. Reprographic copying beyond that permitted by Sections 107 or 108 of the
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PRINTED IN THE UNITED STATES OF AMERICA
In Transition Metal Catalysis in Macromolecular Design; Boffa, L., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 2000.
Foreword
T HE ACS SYMPOSIUM SERIES was first published in 1974 to provide a
mechanism for publishing symposia quickly in book form. The purpose
of the series is to publish timely, comprehensive books developed from
ACS sponsored symposia based on current scientific research.
1
0 Occasionally, books are developed from symposia sponsored by other
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76 audience.
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00- Before agreeing to publish a book, the proposed table of contents is
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k-2 reviewed for appropriate and comprehensive coverage and for interest to
1/b the audience. Some papers may be excluded in order to better focus the
2
0 book; others may be added to provide comprehensiveness. When
1
10. appropriate, overview or introductory chapters are added. Drafts of
oi: chapters are peer-reviewed prior to final acceptance or rejection, and
s.org 00 | d manuscripts are prepared in camera-ready format.
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August 27, Publication

In Transition Metal Catalysis in Macromolecular Design; Boffa, L., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 2000.
Preface
The use of organometallic catalysis as a tool for producing well-defined
macromolecules has advanced rapidly since the development of metallocene and
"living" transition metal-mediated polymerizations. In addition to the continued
understanding and development of controlled addition and condensation poly­
merizations, recent years have seen the discovery of new catalytic chain-building
mechanisms and the achievement of greater levels of control of polymer archi­
tecture. Catalytic reactions involving polymers as substrates have produced many
new macromolecules, and advances in catalyst design have allowed controlled
01 polymerization techniques to be applied under a wider range of conditions.
0
pr This book examines several themes in the area of transition metal-
0.
76 mediated polymer synthesis, with the special intent to demonstrate how this field
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0- has moved beyond the use of single-site catalysts to new applications and
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20 advanced techniques for architectural control. It is based on a symposium that
bk- took place at the 217th National American Chemical Society (ACS) Meeting in
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2 Anaheim, California, April 1999, entitled "Advanced Catalysis: New Polymer
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0. Syntheses and Modifications". We hope this book will serve as a useful
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org 0 | d The book contains 16 chapters, beginning with an overview chapter
cs.00 designed to illustrate how organometallic techniques have advanced the design of
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spirit of this book.
Acknowledgments
We thank all of the chapter authors, primarily for their excellent contri­
butions, but also for their cooperation and timeliness regarding manuscript sub­
mission. We are also grateful for the excellent support of Teresa Henline (North
Carolina State University) and Pat Kocian (Exxon) with chapter reviews and
submissions. Anne Wilson and Kelly Dennis at ACS were critical in helping this
book take shape. Finally, we appreciate the patience of our colleagues, particularly
Joe Sissano and Don Schulz at Exxon, during the preparation of the Advanced
Catalysis symposium and this volume. Financial support for the Advanced
ix
In Transition Metal Catalysis in Macromolecular Design; Boffa, L., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 2000.
Catalysis symposium was provided by the ACS Division of Polymeric Materials:
Science and Engineering, Inc., Exxon Chemical Company, Exxon Research &
Engineering Company, The Goodyear Tire & Rubber Company, and Rohm &
Haas. Acknowledgment is also made to the Donors of The Petroleum Research
Fund, administered by the ACS, for partial support of the symposium through a
Type SE grant.
LISA SAUNDERS BOFFA
Corporate Research Laboratory
Exxon Research & Engineering Company
Route 22 East
Annandale, NJ 08801
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pr0 BRUCE M. NOVAK
60. Department of Chemistry
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00 Raleigh, NC 27695
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In Transition Metal Catalysis in Macromolecular Design; Boffa, L., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 2000.
Chapter 1
The Organometallic Polymerization
of (Meth)acrylates: An Overview
Lisa Saunders Boffa
Corporate Research Laboratory, Exxon Research and Engineering Company,
Route 22 East, Clinton Township, Annandale, NJ 08801
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7 example of the versatility and importance of transition metal
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0- catalysis in polymer design. This chapter surveys several of these
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0 processes with respect to "living" behavior, experimental condition
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k- and monomer restrictions, and types of polymer architectures
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1/ available. In addition to anionic methods, Group Transfer
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10 Polymerization (GTP) with silyl enolates or zirconocenes,
10. organolanthanide- and aluminum porphyrin-initiated polymer­
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temperatures, and as latex emulsions form the basis for durable automobile and house
paints and coatings. Random copolymers of (meth)acrylates with vinylidene chloride
(Sarari), acrylonitrile, and ethylene find applications as clothing fibers, tubing,
gaskets, disposable gloves, and heat- and oil-resistant automotive elastomers.
Despite the commercial utility of polymethacrylates and polyacrylates,
refinements in synthetic methodology these macromolecules have lagged behind that
of other polymers. The great majority of acrylic ester products in use today are still
produced by radical polymerization, which allows little if any control over the fine
points of the polymerization process. This is the result of the traditionally ill-
controlled nature of acrylate polymerization. While chain termination and transfer
side reactions may be largely eliminated for other monomers, such as styrene and
dienes, through the use of controlled anionic polymerization, the (meth)acrylate ester
© 2000 American Chemical Society 1
In Transition Metal Catalysis in Macromolecular Design; Boffa, L., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 2000.
2
group can participate in a number of side reactions during polymerization. For this
reason the control necessary to produce well-defined acrylic macromolecules has been
an elusive goal, and comparatively fewer special-architecture poly(meth)acrylate
materials have been prepared.
The instances in which special-architecture acrylics have been studied indicate
that these materials are both scientifically and technologically appealing. For
example, telechelic polymethacrylates and -acrylates are useful toughening agents (1)
and chain extenders (2) and are known to act as self-assembling rheothickeners (3).
Diene-methyl methacrylate (MMA) diblock copolymers are excellent emulsifiers for
filler blends, liquid dispersions, and high-impact polymeric matrices (4). Acrylics are
predicted to be ideal components for styrene-butadiene-styrene-type triblock
thermoplastic elastomers (5), and new copolymer combinations of (meth)acrylates and
nonpolar monomers should produce interesting amphiphilic materials. A great deal
of effort has thus been expended in the last two decades to develop polymerization
techniques with the control necessary to produce well-defined poly(meth)acrylates of
01 varying architectures. In addition to modified anionic methods, well-controlled or
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07 synthesis of useful and novel materials. These processes, along with a discussion of
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syndiotactic. This mechanism is most highly favored for lithium counterions, which
interact very strongly with the solvent and chain end due to orbital overlap. When
mixed solvents or larger, more weakly interacting cations are used, a mixture of both
mechanisms results, giving largely atactic polymer. A concerted mechanism is also
operable with cryptated cations, which cannot undergo monomer precoordination prior
to addition, and in cases where free ions rather than ion pairs are the active species.
In Transition Metal Catalysis in Macromolecular Design; Boffa, L., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 2000.
3
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Isotactic
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August 27, Publication

Syndiotactic
Scheme 2. Concerted mechanism for methacrylate polymerization (strongly
coordinating solvents).
In Transition Metal Catalysis in Macromolecular Design; Boffa, L., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 2000.