Emulsion Polymerization and Its Applications in Industry

230 Pages·1981·4.972 MB·English

by  V. I. Eliseeva, S. S. Ivanchev, S. I. Kuchanov, A. V. Lebedev (auth.)

EMULSION POLYMERIZATION AND
ITS APPLICATIONS IN INDUSTRY
EMULSION POLYMERIZATION AND
ITS APPLICATIONS IN INDUSTRY
V. I. Eliseeva
S. S. Ivanchev
S. I. Kuchanov
A. V. Lebedev
Translated from Russian by
Sylvia J. Teague
®
CONSULTANTS BUREAU • NEW YORK AND LONDON
Library of Congress Cataloging in Publication Data
Emul'sionnaia polimerizatsiia i ee primenenie v promyshlennosti. English.
Emulsion polymerization and its applications in industry.
Translation of: Emul'sionnaia polimerizatsiia i ee primenenie v promyshlennosti.
Includes index.
1. Emulsion polymerization. I. Eliseeva, V. I. (Valentina I vanovna) II. Title.
QD382.E48E4913 668.9 81-17477
ISBN-13: 978-1-4684-1643-5 e-ISBN-13: 978-1-4684-1641-1 AACR2
DOl: 10.1007/978-1-4684-1641-1
The original Russian text was published by Khimiya in Moscow in 1976. This transla
tion is published under an agreement with the Copyright Agency of the USSR (V AAP).
EMUL'SIONNA YA POLIMERIZAT SIY A I EE PRIMENENIE
V PROMYSHLENNOSTI
3MYnbCHOHHA~ nO~HMEPH3AUH~
H EE nPHMEHEHHE B npOMbllliJIEHHOCTH
© 1981 Consultants Bureau, New York
Softcover reprint of the hardcover 1st edition 1981
A Division of Plenum Publishing Corporation
233 Spring Street, New York, N. Y. 10013
All rights reserved
No part of this book may be reproduced, stored in a retrieval system, or transmitted, in
any form or by any means, electronic, mechanical, photocopying, microfilming,
recording, or otherwise, without written permission from the publisher
Foreword
There is a large body of Soviet work on emulsion polymerization, spanning a
period of over three decades, that has been published primarily in the Russian
language. Most of this has remained untranslated into English and hence un
available to most other scientists. The value of this book lies primarily in the
fact that it brings together the most important of these Soviet contributions,
along with comment and analysis by the authors, who may be considered among
the foremost authorities in this field in the Soviet Union. But the hundreds of
literature citations go far beyond the borders of the Soviet Union and serve as an
excellent bibliography of the world literature on emulsion polymerization up to
the time this book was written.
The book covers both fundamental and applied aspects. In the former are
included discussions of particle formation mechanisms, a comprehensive theory
of emulsion polymerization, copolymerization of polar monomers, and particle
morphology and its implications with regard to derived film properties. Among
the applied aspects are discussions of continuous emulsion polymerization, both
tubular reactors and continuous stirred tank cascades, and various aspects con
cerning the manufacture of some of the most important monomers, such as
styrene, butadiene, vinyl acetate, methyl methacrylate, acrylonitrile, and
chloroprene.
This book will be an indispensable reference source for scientists who are
entering the field as well as those who are experienced and who have wanted a
ready access to this large body of literature.
Robert M. Fitch
Storrs, Connecticut
v
Preface to the English Edition
In view of the growing interest in recent years on the part of production engineers
and scientists in the problem of preparing polymers and latexes by emulsion poly
merization, it seemed desirable to the authors to prepare this monograph to pre
sent experimental data in this area that they and other specialists have collected.
The authors are specialists in various areas of emulsion polymerization, and
they have written different sections of the book, according to their field of
specialization. The authors, systematizing the material available to them, have
developed their own concepts of the process of emulsion polymerization. In so
doing, it seemed to them that the use of modern methods of investigation, the
accumulation of new facts in this area, and the increase in the variety of mono
mers and other components of the polymerization systems have impeded under
standing of the complex process of emulsion polymerization. This process,
apparently, cannot be fitted into a single general scheme, so that each class of
polymerization system requires the creation of a corresponding model taking
into consideration the main physicochemical properties of the class.
A first attempt is made in this book to systematically present data on the
influence of the nature of the interface (which is related to the polarity of the
monomer), the kinetics of the process, the mechanism of particle formation, and
the physical structure of the polymer and copolymer. Research in this area was
first conducted in the Soviet Union.
In describing the emulsion polymerization of hydrophobic monomers, Soviet
work little known abroad is included in the book. This includes research on poly
merization in the presence of nonionic emulsifiers and weakly soluble initiators,
which lead to microdroplets of monomer emulsion; research on the features of
peroxide-initiated polymerization in the presence of cationic emulsifiers; and
research on the activating influence of the interface on the decomposition of
peroxide and the rate of initiation. The book also contains a critical review, in
condensed form, ofthe classical theory of emulsion polymerization and its refine
ment and extension, in particular in works by Soviet investigators.
vii
viii PREFACE TO THE ENGLISH EDITION
In describing industrial methods of emulsion polymerization, the authors
used data from Soviet industrial practice.
It is the hope of the authors that the present monograph will interest foreign
specialists working in the area of emulsion polymerization.
V. I. Eliseeva
Preface
Emulsion polymerization continues to attract the attention of scientists and
industrial workers since the possibilities for this interesting, convenient, and
economical method of preparation of polymers and latexes with various prop
erties are far from exhausted. Ever since the publication in 1955 of a monograph
on emulsion polymerization by American scientists, the scale of research in this
area has increased significantly.
New directions have emerged in the study of emulsion polymerization (ionic
and radiation-initiated polymerization as well as polymerization in nonaqueous
media). Copolymerization with functionally substituted monomers has undergone
broad practical development and the assortment of such monomers grows from
year to year. Interest has also arisen in the study and preparation of monodisperse
latexes with regulated particle size. The range of monomers, emulsifying agents,
and initiating systems being studied has expanded and new methods have appeared
for using latex polymers in technology (particularly for increasing the impact
strength of polymeric glasses) and in agriculture, biology, and medicine.
The increased use of latex polymers has provoked interest in industry in
creating technological schemes for the continuous polymerization of various
monomers. This, in turn, led to the necessity for mathematically describing the
processes.
The development of new phYSicochemical methods of investigation permitted
a new interpretation of the processes of emulsion polymerization taking into
consideration the nature of the interface and intermolecular interactions at the
boundary phase using thermodynamics and conformational statistics. This pro
vided a key to understanding "anomalies" in the polymerization and copolymer
ization of polar monomers. This same approach was used to explain specifics of
the morphology of latex polymers formed at an interface.
The expansion of the variety of necessary components of reactive emulsion
systems (monomers, emulsifiers, initiators, dispersion media) and of production
methods (semicontinuous, continuous) along with increased demands of industry
regarding the properties of the products obtained, have led to new technical and
practical problems in emulsion polymerization. These problems include the ki-
ix
x PREFACE
netics of polymerization of monomers differing in solubility in water, polarity, and
reactivity; copolymerization with multifunctional monomers; the principles of
selecting an emulsifying agent for different polymerization systems; the formation
of polymeric colloids in nonaqueous media; the morphology and structure of
latex polymers; the mechanism of film formation and cross-linking oflatex poly
mers; the automation of production processes of emulsion polymerization; pro
cess optimization; the creation of continuous reactors.
The present monograph covers as completely as possible the aqueous-phase
radical latex polymerization of "classical" monomers such as styrene and the
polymerization and copolymerization of polar monomers, which is assuming ever
greater practical and scientific interest. Whereas the former presently serves as
the basis for large-scale production of rubbers and has been studied more exten
sively, the emulsion polymerization of polar monomers has begun to be system
atically studied only in recent years. Polymers and, especially, copolymers from
polar monomers are widely used in construction and in the film, paint, leather,
textile, paper, etc., industries. Prospects for using such latexes for medical pur
poses have also appeared. In this monograph a systematic review of the latest
research in this area is given first. Also presented is the mathematical theory of
the emulsion polymerization of styrene, an acquaintance with which is necessary
in constructing mathematical models and for optimization of industrial processes.
In addition, this theory suggests an approach to the quantitative description of
the polymerization of other monomers in complex colloidal systems.
The questions of radiation-induced and stereospecific polymerizations, since
they are still in the laboratory and pilot-plant stage, are not included in this book,
and because of space limitations the problems of latex polymerization in non
aqueous media also are not discussed.
It seemed expedient to the authors to deal separately with the emulsion poly
merization of nonpolar monomers such as styrene and of polar monomers such
as vinyl acetate, acrylates, and vinyl chloride as well as the copolymerization of
vinyl monomers with functionally substituted monomers. The expediency of
such a separation arises from the theory advanced that a polymer in the form of
a latex (colloidal dispersion) has new properties that are not characteristic of a
polymer in bulk or in solution and that are caused by the presence of a strongly
developed interface of the polymer and the aqueous phase. The properties of this
interface change in a specific manner with the nature of the polymer and depend
on such processes (important in the synthesis and properties of the products
formed) as adsorption of the surfactant, flocculation of particles, particle inter
action, and conformational behavior of the macromolecules formed. In addition,
this interface can be used as a carrier of chemically, biologically, and catalytically
active groups. This phenomenon should not be overlook.;J during copolymeriza
tion with functionally substituted monomers and it opens up new possible uses
of polymeric materials. Although these factors have been disregarded in the in-
PREFACE xi
vestigation and theoretical examination of the emulsion polymerization of hy
drophobic monomers, in the polymerization and copolymerization of polar
monomers (where molecular interactions at the interface are intensified) the
properties of the interface of polymer colloids are of primary importance both
with respect to the colloidal behavior of the system and the kinetics of the
process.
The chapter devoted to the polymerization of monomers such as styrene
covers problems which began to be studied at the turn of the century and which
are the subject of a large number of works. In this chapter the authors generalize
recent (and mainly) Soviet research in which special attention is given to the
specific action of the emulsifier on the mechanism of initiation and on the kinetics
of the process.
In the chapter devoted to the polymerization and copolymerization of polar
monomers, a systematic report is given of research begun relatively recently.
Considerable attention is given to the nature of the interfacial region and its in
fluence on the kinetics of the process, the behavior of a polymerization system,
and the conformational behavior of the macromolecules formed. For the first
time, an experimental and a quantitative approach is given for evaluating the be
havior of a statistically heterogeneous copolymer macromolecule at its interface;
this approach offers a new means of studying emulsion copolymerization.
In the second part, which is devoted to practical problems, the physico
mechanical principles of the polymerization technology of important monomers
are described. The properties and variety of latexes and polymers derived from
them are also discussed. In writing this book, the authors have striven to present
the latest data and to avoid repetition of previously published material.
Chapter 1 of the book was written by S. S. Ivanchev, Chapter 2 by S. I.
Kuchanov, Chapter 3 by V. I. Eliseeva, Chapters 4 and 8 by A. V. Lebedev,
Chapter 5 by S. S. Ivanchev and E. V. Gromov, Chapter 6 by S. S. Ivanchev and
S. S. Mnatsakanov, and Chapter 7 by V. I. Eliseeva and A. S. Gerasimova.
The authors express deep gratitude to P. M. Khomikovskii for reading the
manuscript and for valuable advice and comments. This book is not without short
comings. All critical comments will be appreciated by the authors.
V. I. Eliseeva
Contents
PART 1
1. EMULSION POLYMERIZATION OF NONPOLAR MONOMERS. . . . 3
Classification of Emulsion Polymerization Systems. . . . . . . . . . . . . . 4
Classification of Systems according to Monomer . . . . . . . . . . . . . 5
Classification of Systems according to the Emulsifier . . . . . . . . . . 6
Classification of Systems according to Initiator. . . . . . . . . . . . . . 7
Role of Emulsifier in Emulsion Polymerization ................ 9
Properties of Emulsifier Solutions ...................... 9
Formation and Structure of Micelles. . . . . . . . . . . . . . . . . . . . . 10
Solubilization of Surfactant Solutions. . . . . . . . . . . . . . . . . . . . 11
Influence of Emulsifier Type on Properties of Monomer Emulsions 12
Role of Ionic Emulsifier . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 13
Role of Nonionic Emulsifier . . . . . . . . . . . . . . . . . . . . . . . . .. 23
Emulsifiers Containing Reactive Functional Groups. . . . . . . . . .. 28
Influence of Initiator on the Kinetics of Polymerization .......... 33
Water-Soluble Initiators . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 38
Initiators Soluble in Monomer. . . . . . . . . . . . . . . . . . . . . . . .. 40
References .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 41
2. QUANTITATIVE DESCRIPTION OF EMULSION
POLYMERIZATION ........ -. . . . . . . . . . . . . . . . . . . . . . .. 47
Smith-Ewart Theory. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 47
Refinement and Extension of the Smith-Ewart Theory. . . . . . . . . .. 56
Average Molecular Weight and Molecular Weight Distribution of
Polymerization Products. . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 67
Size Distribution of Latex Particles . . . . . . . . . . . . . . . . . . . . . . .. 69
References ........................ . . . . . . . . . . . . . . .. 77
3. CHARACTERISTICS OF EMULSION POLYMERIZATION AND
COPOLYMERIZATION OF POLAR MONOMERS. . . . . . . . . . . . .. 79
Deviations from Kinetic Dependences Established for Styrene ...... 80
Mechanism of Particle Nucleation . . . . . . . . . . . . . . . . . . . . . . . .. 86
xiii