Graft Copolymerization of Lignocellulosic Fibers

372 Pages·1982·5.87 MB·English

by  David N.-S. Hon (Eds.)

Graft Copolymerization of
Lignocellulosic Fibers
In Graft Copolymerization of Lignocellulosic Fibers; Hon, D.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1982.
In Graft Copolymerization of Lignocellulosic Fibers; Hon, D.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1982.
Graft Copolymerization of
Lignocellulosic Fibers
Hon,
David N.-S. EDITOR
Virginia Polytechnic Institute
and State University
Based on a symposium
sponsored by the
ACS Division of Cellulose,
Paper, and Textile Chemistry
at the 182nd Meeting of the
American Chemical Society,
New York, New York,
August 23-28, 1981.
ACS SYMPOSIUM SERIES 187
AMERICAN CHEMICAL SOCIETY
WASHINGTON, D. C. 1982
In Graft Copolymerization of Lignocellulosic Fibers; Hon, D.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1982.
Library of Congress Cataloging in Publication Data
Graft copolymerization of lignocellulosic fibers.
(ACS symposium series, ISSN 0097-6156; 187)
"Based on a symposium sponsored by the ACS
Division of Cellulose, Paper, and Textile Chemistry
at the 182nd Meeting of the American Chemical Soci
ety, New York, New York, August 23-28, 1981."
Includes bibliographies and index.
1. Graft copolymers—Congresses
Congresses.
I. Hon, David N.-S. II. American Chemical Society.
Cellulose, Paper, and Textile Division. III. Series.
QD382.G7G73 547.7'82 82-6717
ISBN 0-8412-0721-6 AACR2 ACSMC8 189 1-382
1982
Copyright © 1982
American Chemical Society
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In Graft Copolymerization of Lignocellulosic Fibers; Hon, D.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1982.
ACS Symposium Series
M. Joa
Advisory Board
David L. Allara Marvin Margoshes
Robert Baker Robert Ory
Donald D. Dollberg Leon Petrakis
Robert E. Feeney Theodore Provder
Brian M. Harney Charles N. Satterfield
W. Jeffrey Howe Dennis Schuetzle
James D. Idol, Jr. Davis L. Temple, Jr.
Herbert D. Kaesz Gunter Zweig
In Graft Copolymerization of Lignocellulosic Fibers; Hon, D.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1982.
FOREWORD
The ACS SYMPOSIUM SERIES was founded in 1974 to provide
a medium for publishing symposia quickly in book form. The
format of the Series parallels that of the continuing ADVANCES
IN CHEMISTRY SERIES except that in order to save time the
papers are not typeset but are reproduced as they are sub­
mitted by the authors in camera-ready form. Papers are re­
viewed under the supervision of the Editors with the assistance
of the Series Advisory Board and are selected to maintain the
integrity of the symposia; however, verbatim reproductions of
previously published papers are not accepted. Both reviews
and reports of research are acceptable since symposia may
embrace both types of presentation.
In Graft Copolymerization of Lignocellulosic Fibers; Hon, D.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1982.
PREFACE
T
he shortage of oil and natural gas has been reflected in shortages and
spiraling prices for polymers based on petrochemical resources. Provi­
dentially, such polymers may be in part replaced by lignocellulosic mate­
rials that are the most abundant and most economical organic renewable
resources available. In their natural state as wood and plant fibers, and
as the principal constituent used in the manufacture of paper, textile fibers,
and many other industrial products, lignocellulosic materials will continue
to be fundamental to human welfare
Lignocellulosic material
can be used in their polymeric form without degradation. However, their
properties and performance must be improved before they can compete
with petroehemically derived synthetic polymers. Many new techniques
for improving the competitive position of lignocellulosic materials are
available. The grafting of vinyl monomers onto lignocellulosic fibers is
one of these techniques. However, this technique has need of amendment
to obtain economically feasible grafted lignocellulosic copolymers of
superior quality.
This volume is a collection of topics discussed at a symposium
organized to provide an international forum for discussion of problems and
challenges related to grafting reactions of lignocellulosic materials. Par­
ticipating scientists were invited from Australia, Bangladesh, Canada,
Egypt, France, India, Japan, Romania, Sweden, Taiwan, and the United
States.
This volume contains the latest information on grafting reactions
important to the polymer, fiber, and wood products industries. Chapters
of this volume are divided into four general categories dealing with graft­
ing reactions of (1) cellulose and cellulose derivatives, (2) starch and
bamboo, (3) lignocellulosic fibers, and (4) chemically modified ligno­
cellulosic fibers. These chapters provide only a small sampling of the
activity in the field and the high level of interest in grafting research is
continuing. One can thus look forward to a vigorous activity in this area.
It is hoped that this volume will be timely and helpful and will serve as a
source of information and a base from which further development of the
science and technology of grafted lignocellulosics can emerge.
Finally, I would like to thank all of the patient and enthusiastic con­
tributors who prepared the manuscripts, participated as speakers at the
ix
In Graft Copolymerization of Lignocellulosic Fibers; Hon, D.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1982.
symposium, and reviewed the papers of this volume. Special thanks also
go to V. Stannett (North Carolina State University) and Roger Rowell
(USDA Forest Products Laboratory) for chairing sessions at the sym­
posium.
DAVID N.-S. HON
Virginia Polytechnic Institute
and State University
Department of Forest Products
Blacksburg, Virginia 24061
December 1, 1981
x
In Graft Copolymerization of Lignocellulosic Fibers; Hon, D.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1982.
1
Some Challenges in Grafting to Cellulose and
Cellulose Derivatives
V. STANNETT
North Carolina State University, Department of Chemical Engineering,
Raleigh, NC 27650
Grafting reactions to cellulose and its derivatives
began in the early 1950's There has been intense
research and developmen
those early day
patents have been published. In spite of all this
effort there has been comparatively little commer­
cialization of the grafting process. The turning
around of this situation represents the greatest
challenge to those of us who are active in the field.
The reasons for the lack of industrialization on a
large scale have been partly economic and partly
the ability of researchers to find alternative means
to achieve comparable properties. The author feels,
however, that the situation will change once certain
technical challenges are met. A number of these are
discussed together with some still promising fields
of application. Among the technical problems which
still remain to a considerable extent are the con­
current formation of homopolymer in most cases, and
the lack of reproducibility in these largely heter­
ogeneous reactions. In addition, the grafted side
chains are often too few and too long, leading to a
limited involvement also of the cellulose molecules
themselves. Although there is often some concurrent
degradation of the cellulose itself, this is not
believed to be normally an important consideration.
Conscious grafting to cellulose was first reported in 1953
(1) , although relevant and somewhat earlier work in the U.S.S.R.
(2) and in England (3) certainly preceded it. This work was
variously described as copolymerization, actually accompanied by
extensive crosslinking (2), and as polymer deposition (3). The
author was privileged to follow on the 1953 work that same year
and has continued to work in the field since that time.
0097-6156/82/0187-0003$6.00/0
© 1982 American Chemical Society
In Graft Copolymerization of Lignocellulosic Fibers; Hon, D.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1982.
4 GRAFT COPOLYMERIZATION OF LIGNOCELLULOSIC FIBERS
The possibility of grafting synthetic polymers to cellulose
immediately attracted worldwide attention as a new and exciting
way to modify cellulose and extend its uses against the rapidly
growing competition from synthetic polymers themselves. The well
known phrase attributed to Theodore Roosevelt, "if you can't beat
them, join them", if somewhat trite, seems particularly appropri
ate at this point. Research in the field blossomed quickly and
is still an extremely active subject of study. For example, in a
very recent (and the first) book on the subject by Hebeish and
Guthrie (4) more than one thousand references are quoted.
In spite of these enormous efforts, there is still no large-
scale commercial application of cellulose graft copolymers. The
reasons for this situation and the challenge it represents to
cellulose and polymer scientists and engineers will be the sub
ject of this introductor
such a discussion into th
ization, properties and, finally, applications. The discussion
will be mainly devoted to cellulose itself, although grafting to
cellulose derivatives has also been actively pursued.
Synthesis of Cellulose Graft Copolymers
This area of research has almost totally dominated the field
and continues to do so, partly because of the patent opportuni
ties which arise. There are now a considerable number of methods
available, each with its own particular advantages and disadvan
tages. Many of the methods are discussed in this symposium ser
ies. Among the older methods, studies of redox systems, direct
oxidation and high energy radiation are presented. The compara
tively new method, but actually developed by the Scott Paper Co.
as early as 1964, is also discussed (5). There seems to be a
growing interest in the use of uv for surface grafting to cellu
lose and considerable work by Arthur (6), Garnett (7), Hon (8) and
others has been reported in recent years. Plasma bas also been
investigated, but to a lesser extent, by Yasuda, Simionescu and
their colleagues, among others, again for surface modifications.
Extensive reviews of work up to 1965 and 1970 have been presented
by Krassig and Stannett (9) and by Arthur (10), respectively.
The whole field, including quite recent development, has been
described by Hebeish and Guthrie (4). Until recently all the syn
thetic approaches have been heterogeneous reactions, i.e., to
cellulose fibers, film and powder. This is clearly more conven
ient, especially in the absence of practical solvent systems for
cellulose itself. Recently, however, Shiraishi et_ al. (11,12)
have carried out grafting to cellulose in some of the newer cellu
lose solvents. In principle, this type of grafting would become
practical if it could be followed by direct spinning or film
casting. Alternatively, powdered, fibrous or granular products
could be obtained by precipitation. It is interesting and impor
tant that Shiraishi et_ al. (12) did use the thin layer technique
In Graft Copolymerization of Lignocellulosic Fibers; Hon, D.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1982.