Developments in Rubber Technology—4

316 Pages·1987·9.69 MB·English

by  I. G. Hargis

DEVELOPMENTS IN RUBBER TECHNOLOGY-4
CONTENTS OF VOLUMES 2 and 3
Volume 2: Synthetic Ruhbers
1. Trends in the Usage of Rubbery Materials. J. A. BRYDSON
2. Styrene-Butadiene Rubber. J. A. BRYDSON
3. Developments in Acrylonitrile-Butadiene Rubber (NBR) and Future Prospects. H.
H. BERTRAM
4. Ethylene-Propylene Rubbers. L. CORBELLI
5. Developments with Polychloroprene. J. C. BAMENT and J. G. PILLOW
6. Butyl and Halogenated Butyl Rubbers. W. D. GUNTER
7. Silicone Rubbers. R. J. CUSH and H. W. WINNAN
8. Synthetic Polyisoprene Rubbers. M. J. SHlJTILEWORTII and A. A. WATSON
Index
Volume 3: Thermoplastic Rubbers
1. Thermoplastic Rubbers-An Introductory Review. J. A. BRYDSON
2. Ethylene-Propylene Rubber-Polypropylene Blends. R. RANALLI
3. Styrenic Block Copolymers. F. MiSTRALI and A. PRONI
4. Ethylene-Vinyl Acetate Copolymers. G. W. GILBY
5. Thermoplastic Polyurethanes. D. J. HARRop
6. Polyester Elastomers. I. R. LLOYD
7. Natural Rubber Systems. D. J. ELLIOTT
Index
DEVELOPMENTS
IN RUBBER
TECHNOLOGY 4
Edited by
A. WHELAN and K. S. LEE
London School of Polymer Technology
(formerly National College of Rubber Technology),
Holloway, London, UK
ELSEVIER APPLIED SCIENCE
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WITH 91 TABLES AND 113 ILLUSTRATIONS
© ELSEVIER APPLIED SCIENCE PUBLISHERS LTD 1987
Softcover reprint of the hardcover 1st edition 1987
British Library Cataloguing in Publication Data
Developments in rubber technology. - 4
1. Elastomers 2. Rubber
678 TS1925
The Library of Congress has cataloged this work as follows:
Developments in rubber technology. -1-- London: Applied
Science Publishers, 1979-
v.: ill.; 23 cm. - (Developments series)
ISSN 0262-1584 = Developments in rubber technology.
1. Rubber-Collected works. 2. Rubber, Artificial-Collected works. I.
Series.
[DNAL: 1. Rubber industryap.d trade:-:",Periodicals]
TS1870.D49 678' .2'05--dCl9 84-644558
ISBN-13: 978-94-010-8037-8 e-ISBN-13: 978-94-009-3435-1
DOl: 10.1007/978-94-009-3435-1
The selection and presentation of material and the opinions expressed are the sole
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PREFACE
This volume, the fourth in a series which began in 1979, covers a
greater variety of subjects than any previous single volume. The basis
of selection has been topical interest; hence the tailor-making of
polymers to develop specific properties, methods of improving com
pound processability and the use of rubbers in the oil industry are
featured alongside a discussion of safety aspects.
We have again sought the cooperation of the foremost authorities
on the chosen subjects and have been delighted at the response which
has yielded a list of authors of international repute.
A.w.
K.S.L.
CONTENTS
Preface v
List of Contributors ix
1. Recent Developments in Synthetic Rubbers by Anionic
Polymerization 1
I. G. HARGIS, R. A. LIVIGNI and S. L. AGGARWAL
2. Advances in Nitrile Rubber (NBR) 57
P. W. MILNER
3. Epoxidized Natural Rubber. 87
C. S. L. BAKER and I. R. GELLING
4. Process Aids and Plasticizers . 119
B. G. CROWTHER
5. A Review of Elastomers Used for Oilfield Sealing
Environments . 159
W. N. K. REVOLTA and G. C. SWEET
6. Using Modern Mill Room Equipment . 193
H. ELLWOOD
7. Quality Requirements and Rubber Mixing . 221
P. S. JOHNSON
8. Health and Safety . . 253
B. G. WILLOUGHBY
Index . 307
vii
LIST OF CONTRIBUTORS
s.
L. AGGARWAL
Gen Corp , Research Division, 2990 Gilchrist Road, Akron, Ohio
44305, USA
C. S. L. BAKER
Malaysian Rubber Producers' Research Association, Tun Abdul
Razak Laboratory, Brickendonbury, Hertford SG13 8NL, UK
B. G. CROWTHER
Malaysian Rubber Producers' Research Association, Tun Abdul
Razak Laboratory, Brickendonbury, Hertford SG13 8NL, UK
H. ELLWOOD
Farrel Bridge Ltd, Queensway, Castleton, PO Box 27, Rochdale,
Lancashire OLll 2PF, UK
I. R. GELLING
Malaysian Rubber Producers' Research Association, Tun Abdul
Razak Laboratory, Brickendonbury, Hertford SG13 8NL, UK
I. G. HARGIS
GenCorp, Research Division, 2990 Gilchrist Road, Akron, Ohio
44305, USA
ix
x LIST OF CONTRIBUTORS
P. S. JOHNSON
Polysar Ltd, Sarnia, Ontario N7V 7Ul, Canada
R. A. LIVIGNI
GenCorp, Research Division, 2990 Gilchrist Road, Akron, Ohio
44305, USA
P. W. MILNER
Compagnie Franfaise Goodyear, Avenue des Tropiques, ZA
Courtaboeuf, BP 31, 91941 Les Ulis Cedex, France
W. N. K. REVOLTA
Du Pont (UK) Ltd, Maylands Avenue, Hemel Hempstead, Herts
HP27DP, UK
G. C. SWEET
Du Pont (UK) Ltd, Maylands Avenue, Hemel Hempstead, Herts
HP27DP, UK
B. G. WILLOUGHBY
Rapra Technology Ltd, Shawbury, Shrewsbury, Shropshire SY4
4NR, UK
Chapter 1
RECENT DEVELOPMENTS IN SYNTHETIC
RUBBERS BY ANIONIC POLYMERIZATION
I. G. HARGIS, R. A. LIVIGNI and S. L. AGGARWAL
GenCorp, Research Division, Akron, Ohio, USA
1. INTRODUCTION
Although styrene-butadiene rubbers made in organic solvents (com
monly called solution SBR) were introduced commercially in early
1960, their use has been limited to only a few structural varieties.
Emulsion SBRs in blends with cis-BR (high cis-polybutadiene rub
bers) were capable of meeting several performance requirements until
the demand for low rolling resistance of tyre treads came to promin
ence in the 1970s. Then the potential of solution rubbers, with their
much greater control of molecular structure, surfaced to meet the new
requirements for improvements in rolling resistance and wet traction.
The objective of this chapter is to provide a survey of the
technological developments in solution rubbers prepared by homoge
neous anionic polymerization. Emphasis will be on butadiene and
styrene monomers, and catalyst systems based on organolithiums and
their complexes with Lewis bases plus some unpublished work on
alkaline earths from the authors' laboratory. The rubbers thus
obtained offer means for control of molecular structural features of
polybutadiene and poly(butadiene-co-styrene) that directly relate to
the functional properties of tyre rubbers.
1
2 I. G. HARGIS, R. A. LIVIGNI AND S. L. AGGARWAL
2. POLYMER SYNTHESIS AND CHARACTERIZATION
2.1. Early Work on Diene Polymerizations
Early work bearing on organolithium-initiated diene polymerization
was reported by Ziegler and co-workers in 1934.1-3 It was demon
strated that the organolithium adds to the diene double bond to give
an intermediate capable of reacting further with the diene.
The characteristics of the organolithium-initiated polymerization of
the dienes was clearly established by Morton and co-workers. It was
demonstrated that the polymerizations are of the 'living' type, which
take place without a chain termination reaction in the absence of
impurities.4,5 The implications of this behaviour in preparing polymers
of controlled structure are well recognized today.
Homopolymers and copolymers with tailored-molecular structure,
prepared using organolithium, have recently generated much interest
because of their potential for improving rolling efficiency, wet traction
and durability of tyre treads.
2.2. Organolithinm Initiation of Dienes
Anionic polymerization requires unsaturated monomers having sub
stituents that stabilize the negative charge on the active centre
(electrophilic substituents) and initiators based on the most electro
positive elements. Among initiators for diene polymerizations, or
ganolithiums are nearly ideal compounds. This stems from some of
their main characteristics listed in Table 1. Solubility in non-polar
solvents results from their covalent character and their ability to form
electron-deficient bonding giving rise to associated forms, usually
tetramers or hexamers.
TABLE 1
CHARACfERISTICS OF ORGANOLITHIUM POLYMERIZATION
CATALYSTS
(1) Solubility in non-polar solvents.
(2) Associated structures.
(3) Reactivity varies with Lewis bases.
(4) High 1,4-polydienes.
(5) Living Polymerization.
(6) Control of molecular weight and molecular weight
distribution.
(7) Versatility in solution polymerization.