HANDBOOK OF
`THERMOPLASTICS
`
`
`
`EDITED BY
`OLAGOKE OLABISI
`
`PAGE 1 OF 71
`
`PETITIONERS' EXHIBIT 1131
`
`PAGE 1 OF 71
`
`PETITIONERS' EXHIBIT 1131
`
`

`

`F1' MEADE
`GenColl
`
`---(cid:173)
`
`TP 1180
`.15 H36
`',1997
`Copy 2
`
`PAGE 2 OF 71
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`PAGE 3 OF 71
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`

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`HANDBOOK OF
`HANDBODK 0F
`THERMOPLASTICS
`
`THERMOPLASTIGS
`
`PAGE 4 OF 71
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`

`

`PLASTICS ENGINEERING
`
`Founding Editor
`
`Donald E. Hudgin
`
`Professor
`Clemson University
`Clemson, South Carolina
`
`1 . Plastics Waste: Recovery of Economic Value, Jacob Leidner
`2. Polyester Molding Compounds, Robert Burns
`3. Carbon Black-Polymer Composites: The Physics of Electrically Conducting
`Composites, edited by Enid Keil Sichel
`4. The Strength and Stiffness of Polymers, edited by Anagnostis E. Zach
`ariades and Roger S. Porter
`5. Selecting Thermoplastics for Engineering Applications, Charles P. Mac(cid:173)
`Dermott
`6. Engineering with Rigid PVC: Processability and Applications, edited by I.
`Luis Gomez
`7. Computer-Aided Design of Polymers and Composites, D. H. Kaelble
`8. Engineering Thermoplastics: Properties and Applications, edited by James M.
`Margolis
`9. Structural Foam: A Purchasing and Design Guide, Bruce C. Wendle
`1 0. Plastics in Architecture: A Guide to Acrylic and Polycarbonate, Ralph
`Montella
`11. Metal-Filled Polymers: Properties and Applications, edited by Swapan K.
`Bhattacharya
`12. Plastics Technology Handbook, Manas Chanda and Sa/if K. Roy
`13. Reaction Injection Molding Machinery and Processes, F. Melvin Sweeney
`14. Practical Thermoforming: Principles and Applications, John Florian
`15. Injection and Compression Molding Fundamentals, edited by Avraam I.
`/sayev
`16. Polymer Mixing and Extrusion Technology, Nicholas P. Cheremisinoff
`17. High Modulus Polymers: Approaches to Design and Development, edited by
`Anagnostis E. Zachariades and Roger S. Porter
`18. Corrosion-Resistant Plastic Composites in Chemical Plant Design, John H.
`,
`Mallinson
`19. Handbook of Elastomers: New Developments and Technology, edited by
`Ani/ K. Bhowmick and Howard L. Stephens
`20. Rubber Compounding: Principles, Materials, and Techniques, Fred \1\1.
`Barlow
`21 . Thermoplastic Polymer Additives: Theory and Practice, edited by John T.
`Lutz, Jr.
`22. · Emulsion Polymer Technology, Robert D. Athey, Jr.
`23. · Mixing in Polymer Processing, edited by Chris Rauwendaa/
`
`PAGE 5 OF 71
`
`

`

`24. Handbook of Polymer Synthesis, Parts A and B, edited by Hans R.
`Kricheldort
`25. Computational Modeling of Polymers, edited by Jozef Bicerano
`26. Plastics Technology Handbook: Second Edition, Revised and Expanded,
`Manas Chanda and Sa/if K. Roy
`27. Prediction of Polymer Properties, Jozef Bicerano
`28. Ferroelectric Polymers: Chemistry, Physics, and Applications, edited by
`Hari Singh Nalwa
`29. Degradable Polymers, Recycling, and Plastics Waste Management, edited
`by Ann-Christine Albertsson and Samuel J. Huang
`30. Polymer Toughening, edited by Charles B. Arends
`31. Handbook of Applied Polymer Processing Technology, edited by Nicholas P.
`Cheremisinoff and Paul N. Cheremisinoff
`32. Diffusion in Polymers, edited by P. Neogi
`33. Polymer Devolatilization, edited by Ramon J. Albalak
`34. Anionic Polymerization: Principles and Practical Applications, Henry L. Hsieh and
`Roderic P. Quirk
`35. Cationic Polymerizations: Mechanisms, Synthesis/ and Applications, edited by
`Krzysztof Matyjaszewski
`36. Polyimides: Fundamentals and Applications, edited by Malay K. Ghosh and K. L.
`Mittal
`3 7. Thermoplastic Melt Rheology and Processing, A. V. Shenoy and D. R. Saini
`38. Prediction of Polymer Properties: Second Edition, Revised and Expanded, Jozef
`Bicerano
`39. Practical Thermoforming: Principles and Applications, Second Edition, Revised
`and Expanded, John Florian
`40. Macromolecular Design of Polymeric Materials, edited by Koichi Hatada, Tatsuki
`Kitayama, and Otto Vogl
`41. Handbook of Thermoplastics, edited by Olagoke Olabisi
`42. Selecting Thermoplastics for Engineering Applications: Second Edition, Revised
`and Expanded, Charles P. MacDermott and Aroon V. Shenoy
`
`Additional Volumes in Preparation
`
`\
`
`PAGE 6 OF 71
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`

`

`HANDBOOK OF
`H_ THERMOPLASTICS
`
`EDITED BY
`OlAGOKE OlABISI
`King Fahd University of Petroleum and Minerals
`Dhahran, Saudi Arabia
`
`MARCEL DEKKER, INc.
`
`NEw YoRK • BASEL • HoNG KoNG
`
`PAGE 7 OF 71
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`

`Library of Congress Cataloging-in-Publication Data
`
`Handbook of thermoplastics I edited by Olagoke Olabisi.
`p. em.- (Plastics engineering; 41)
`Includes index.
`ISBN 0-8247-9797-3 (he : alk. paper)
`I. Olabisi, Olagoke.
`1. Thermoplastics-Handbooks, manuals, etc.
`II. Series: Plastics engineering (Marcel Dekker, Inc.) ; 41.
`TP1180.T5H36 1997
`668.4'23-dc21
`
`97-58 .
`
`--------CIP
`
`The publisher offers discounts on this book when ordered in bulk quantities. For more
`information, write to Special Sales/Professional Marketing at the address below.
`
`This book is printed on acid-free paper.
`
`Copyright© 1997 by MARCEL DEKKER, INC. All Rights Reserved.
`
`Neither this book nor any part may be reproduced or transmitted in any form or by any
`means, electronic or mechanical, including photocopying, microfilming, and recording,
`or by any information storage and retrieval system, without permission in writing from
`the publisher.
`
`MARCEL DEKKER, INC.
`270 Madison Avenue, New York, New York 10016
`
`Current printing (last digit):
`10 9 8 7 6 5 4 3 2 1
`
`PRINTED IN THE UNITED STATES OF AMERICA
`
`PAGE 8 OF 71
`
`

`

`To the memory of my mother
`Maria Qlapade Qlabisi
`and my father
`Joseph Qna<;>lap<;> Qlabisi
`Ji sun reo
`
`iii
`
`PAGE 9 OF 71
`
`

`

`-
`
`Preface
`
`The global thermoplastics market, representing approximately 10% of the worldwide chem(cid:173)
`ical industry, is the fastest growing segment of the world economy. This growth is being
`driven by several forces, among which are the following: (a) the widening sphere as well
`as the demanding requirements of the emerging thermoplastics applications; (b) the need to
`conserve the dwindling natural resources and the environment; (c) competitive basic,
`mission-oriented, and applied R&D (corporate, national, or international); and (d) the rev(cid:173)
`olutionary and evolutionary scientific and technological innovations that indicate that sci(cid:173)
`entists and engineers, in a paradigm shift, are making a fundamental break from the past.
`«Tailor-made" materials with controlled microstructures are beginning to emerge not only in
`polyolefins and other commodity thermoplastics, but also in polar thermoplastics, thermo(cid:173)
`plastics elastomers, synthetic water soluble thermoplastics, high performance thermoplastics,
`high temperature thermoplastics, specialty thermoplastics for super-function membranes, con(cid:173)
`ducting thermoplastics, polymeric nonlinear optical (NLO) materials systems, liquid crys-
`·
`talline polymers, and advanced thermoplastics composites for structural applications.
`This Handbook of Thermoplastics underscores these emerging developments and
`serves as an authoritative source for a worldwide audience in industry, academia, govern(cid:173)
`ment and nongovernment organizations. It provides comprehensive, up-to-date coverage
`for each thermoplastic in terms of the following:
`
`• History, development, and commercialization milestones
`• Polymer formation mechanisms and process technologies
`• Structural and phase characteristics as they affect use properties
`• Blends, alloys, copolymers, composites and their commercial relevance
`• Processing, performance properties, and applications
`• Any other issue that relates to current and prospective developments in science,
`t~chnology, environmental impact, and commercial viability
`
`v
`
`PAGE 10 OF 71
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`

`vi
`
`Preface
`
`These points were regarded as guidelines and every contributor was urged to choose
`a polymer-specific format that would make the handbook a timeless reference. A thorny
`element for each author, and indeed a most important issue that will continue to challenge
`the thermoplastics industry into the next century, relates to environmental waste. The
`industry has worked long and hard to develop products capable of withstanding extreme
`and/or aggressive conditions and having a long life. The rapid proliferation of thermoplastics
`in an impressive array of applications is evidence of the success of the thermoplastics
`industry, but this very success implies that many thermoplastics, discarded after they have
`fulfilled their purposes, will pose a formidable disposal challenge.
`The Handbook of Thermoplastics is composed of 42 chapters prepared by 70 con(cid:173)
`tributors from 18 countries. It contains more than 4000 bibliographic citations plus over
`. 500 tables and figures. Each chapter includes full references at the end of each chapter.
`Each chapter has been edited, reviewed and revised where necessary, but the authors are
`responsible for the content. Although no attempt was made to rigorously group the chapters
`into subsections, there are some subtle groupings as well as grouping overlaps. This is
`inspired by the reality of the changing thermoplastics industry with its overlapping product
`families, flexible output, and thermoplastics applications. A pragmatic approach was taken,
`based on the conventional wisdom embodied in the broad classification of thermoplastics
`in terms of their applications loosely superimposed on their general spectrum of perfor(cid:173)
`mance properties, namely, commodity, transitional, engineering, high performance, and
`high temperature. The final outcome, representing a cohesive treatment premised on this
`particular perspective, illustrates the phenomenal progress and the still evolving panoply
`of thermoplastics.
`The first 12 chapters focus on polymeric materials that are essentially ethenoid in
`origin. Chapters 1 and 2 are devoted to polyolefins; Chapters 2, 3, and 4 treat stereoregular
`nonpolar and polar thermoplastics; and Chapters 4, 6, and 7 relate to styrenic thermo(cid:173)
`plastics. Water-soluble polymers (Chapters 12 and 13) are discussed prior to the thermo(cid:173)
`plastics based on cellulose (Chapter 14), the most abundant organic substances found in
`nature. Elastomeric materials are discussed in Chapters 15, 16, and 17. The polyester(cid:173)
`based polymers are covered in Chapters 17-20, while polyarylates (Chapter 25), which
`are wholly aromatic polyesters, and the Hquid crystalline polymers (Chapter 41), which
`include a significant percentage of polyester-based materials, appear independently because
`of their uniqueness.
`The compatibilized thermoplastic blends (Chapter 21) are intimately related to, and
`indeed form the basis for, some of the key methods used in the toughening of thermo(cid:173)
`plastics (Chapter 22). The current and emerging engineering, high performance, and high
`temperature thermoplastics are contiguous to each other (Chapters 18-20, 23-33, and
`36-41), interspersed with a few general but related chapters. To achieve some dovetailing,
`the chapters on conducting thermoplastics (Chapter 34) and conducting thermoplastics
`composites (Chapter 35) are placed after polyphenylene sulfide [PPS] (Chapter 32) and
`polyphenylene vinylene [PPV] (Chapter 33). This is because PPV, even without a doping
`agent, possesses a good measure of intrinsic conductivity, and PPS, upon doping with
`selected agents, is capable of significant electron conductivity. The advanced thermoplas(cid:173)
`tics composites (Chapter 42) are discussed last to permit the prerequisite discussion of the
`relevant matrix materials on which the various composites are based.
`It is hoped that this single-volume collective work will serve its intended purposes,
`contributing to the dialogue on questions that will continue to arise: What should be the
`priorities and targets for future development and future investments in the thermoplastics
`industry? What are the prospective developmental patterns? What will be the available
`
`PAGE 11 OF 71
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`

`

`Preface
`
`vii
`
`opportunities and the prevailing threats? What are the possible strategic approaches? What,
`in short, are the new sets of thermoplastics products that are likely to be produced and
`what process technologies are likely to be used to manufacture them in the 21st century
`and beyond?
`The efforts of the contributors in preparing and revising their manuscripts for the
`handbook are deeply appreciated. During the course of preparing her manuscript, the
`author of Chapter 4, Vittoria Vittoria, lost her husband, Francesco de Candia, who made
`outstanding contributions to the study of syndiotactic polystyrene. I commend her forti(cid:173)
`tude; her contribution is an essential memorial essay. Life, they say, is intimately entwined
`with death. I congratulate Emilia Di Pace on the birth of a child during the course of
`preparing her co-authored manuscript. I am delighted to thank M. Jamal El-Hibri for his
`support and for relaying information to some specific contributors. I acknowledge the
`support of the Research Institute, King Fahd University of Petroleum and Minerals, Dhah(cid:173)
`ran, Saudi Arabia. As always, I am indebted to my wife and friend, Juliet Enakeme Olabisi,
`for a considerable amount of assistance, and to the youngest members of the family(cid:173)
`Toyosi, Wande, and Simisola-who, though apparently unimpressed by the handbook
`project, diligently handled the attendant volume of fax messages.
`
`Olagoke Olabisi
`
`PAGE 12 OF 71
`
`

`

`Contents
`
`Preface
`
`Contributors
`
`1. Conventional Polyolefins
`Olagoke Olabisi
`
`2. New Polyolefins
`Michael Arndt
`
`3. Stereoregular Polar Thermoplastics
`Olagoke Olabisi and Michael Arndt
`
`4. Syndiotactic Polystyrene
`Vittoria Vittoria
`5. Unplasticized Polyvinyl Chloride (uPVC): Fracture and
`Fatigue Properties
`Ho-Sung Kim and Yiu-Wing Mai
`6. Acrylonitrile-Butadiene-Styrene (ABS) Polymers
`Moh Ching Oliver Chang, Benny David, Trishna Ray-Chaudhuri,
`Liqing L. Sun, and Russell P. Wong
`
`7. Styrene Copolymers
`Martin J. Guest
`
`8. Polyacrylonitrile
`J ohannis C. Simitzis
`
`v
`
`xiii
`
`1
`
`39
`
`57
`
`81
`
`107
`
`135
`
`161
`
`177
`
`ix
`
`PAGE 13 OF 71
`
`

`

`X
`
`9. Polyacrylates
`Thomas P. Davis
`
`10. Polyacrylamides
`David Hunkeler and Jose Hernandez Barajas
`11. Vinyl Acetate Polymers
`C. Fonseca
`
`12. Vinyl Alcohol Polymers
`Shuji Matsuzawa
`13. Synthetic Water-Soluble Polymers
`Edgar Bortel
`
`14. Cellulose Plastics
`David N. -S. Hon
`15. Thermoplastic Elastomers
`Naba K. Dutta, Anil K. Bhowmick, and Namita Roy Choudhury
`16. Thermoplastic Polyurethanes
`Kuo-Huang Hsieh, Der-Chau Liao, and Yuan-Chen Chern
`17. Polyester-Based Thermoplastic Elastomers
`R. W. M. van Berkel, Rein J. M. Borggreve, C. L. van der Sluijs,
`and G. H. Werumeus Buning
`
`18. Thermoplastic Polyesters
`Miguel Arroyo
`
`19. Polyethylene Terephthalate
`Stoyko Fakirov
`
`20. Polybutylene Terephthalate
`R. W. M. van Berkel, Edwin A. A. van Hartingsveldt,
`and C. L. van der Sluijs
`
`21. Compatibilized Thermoplastic Blends
`Feng-Chih Chang
`
`22. Toughening of Thermoplastics
`Ka11cheng Mai and Jiarui Xu
`
`23. Polyacetal
`Wen-Yen Chiang and Chi-Yuan Huang
`24. Polyethers
`Christo B. Tsvetanov
`
`25. Polyarylates
`Miguel Arroyo
`
`26. Polycarbonates
`Hoang T. Pham, Sarat Munjal, and Clive P. Bosnyak
`27 . . · Polyamides
`Michail Evstatiev
`
`Contents
`
`203
`
`227
`
`253
`
`269
`
`291
`
`331
`
`349
`
`381
`
`397
`
`417
`
`449
`
`465
`
`491
`
`523
`
`557
`
`575
`
`599
`
`609
`
`641
`
`PAGE 14 OF 71
`
`

`

`Contents
`
`28. Polyimides
`M oriyuki Sato
`
`29. Polybenzimidazoles
`Tai-Shung Chung
`
`30. Aromatic Polyhydrazides and Their Corresponding Polyoxadiazoles
`Emilia DiPace, Paola Laurienzo, Mario Malinconico,
`Ezio Martuscelli, and Maria Grazia Volpe
`
`31. Polyphenylquinoxalines
`Maria Bruma
`
`32. Polyphenylene Sulfide
`Gabriel 0. Shonaike
`
`33. Polyphenylene Vinylene
`Louis M. Leung
`34. Conducting Thermoplastics
`Sukumar Maiti
`
`35. Conducting Thermoplastics Composites
`Ming Qui Zhang and Han Min Zeng
`
`36. Poly(aryl ether sulfone)s
`M. Jamal El-Hibri, Jon Nazabal, Jose I. Eguiazabal,
`and Andone Arzak
`
`37. Poly(aryl ether ketone)s
`Mukerrem Cakmak
`
`38. Poly(aryl ether ketones-co-sulfones)
`Jacques Devaux, Veronique Carlier, and Yann Bourgeois
`
`39. Poly(aryl ether ketone amide)s
`Mitsuru Ueda
`
`40. Polytetrafluoroethylene
`Thierry A. Blanchet
`
`41. Liquid Crystalline Polymers
`Francesco P. La Mantia and Pierluigi L. Magagnini
`42. Advanced Thermoplastics Composites
`Gianfranco Carotenuto, M, Giordano, and Luigi Nicolais
`
`Index
`
`xi
`
`665
`
`701
`
`733
`
`771
`
`799
`
`817
`
`837
`
`873
`
`893
`
`931
`
`951
`
`975
`
`981
`
`1001.
`
`1017
`
`1035
`
`PAGE 15 OF 71
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`

`

`1
`Conventional Polyolefins
`
`Olagoke Olabisi*
`King Fahd University of Petroleum and Minerals, Dhahran,
`Saudi Arabia
`
`I.
`
`INTRODUCTION
`
`The global thermoplastics market, representing approximately 10% of the global chemical
`industry [1], was about 90 million tons in 1995, 60% of which is accounted for by
`polyolefins. This percentage is made up of 16% low-density polyethylene (LDPE), 16%
`high-density polyethylene (HDPE), 9% linear low-density polyethylene (LLDPE), and
`19% polypropylene (PP) homo- and copolymers [2]. It was in 1933 that polyethylene was
`discovered by the ICI research scientists Fawcett and Gibson [3] who polymerized ethylene
`using less than 0.2% oxygen as an initiator, at 200°C and pressures of 0.1-0.3 GN/m2
`•
`The first commercial plant was in operation in September 1939 and by the early 1940s
`LDPE production was already based on two high-pressure technologies, namely, autoclave
`reactor and tubular reactor, yielding two significantly different product streams primarily
`for extrusion coatings and film production, respectively. These two parallel developments
`have persisted until today with overlapping product range and, since the late 1970s, both
`technologies have been adapted for the production of HDPE, LLDPE, and medium-density
`polyethylene (MDPE).
`The first solution phase process for the production of linear HDPE, at 100-250°C
`and pressures of 3-5 MN/m2
`, was carried out independently, in 1951-1952, by the Stan(cid:173)
`dard Oil of Indiana (now AMOCO) and Phillips Petroleum Company with the use of
`transition metal oxide catalysts [4,5], i.e., molybdenum oxide and chromium oxide, re(cid:173)
`spectively. Polymer recovery was effected by vaporizing the solvent. By the 1960s, catalyst
`development efforts enabled the low-temperature production of linear HDPE solid using
`a slurry phase reactor with an inert solvent. High-activity catalyst developed by the middle
`of 1960 finally enabled the introduction of gas phase ethylene polymerization and today
`several variants of these processes are in operation in different parts of the world. High-
`
`*Current affiliation: Saudi Aramco, Dhahran, Saudi Arabia.
`
`1
`
`PAGE 16 OF 71
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`

`

`2
`
`Olabisi
`
`activity chromium oxide catalysts are used today in the production of LLDPE in the new(cid:173)
`generation solution and gas phase processes, and the medium-density version is made in
`slurry phase processes. The production of polypropylene followed a similar trend except
`that it normally lags behind.
`The other type of ionic polymerization process for the production of linear HDPE
`became a reality in 1953 when Karl Ziegler discovered [6] the revolutionary first-gener(cid:173)
`ation transition metal halide catalyst with its aluminum alkyl cocatalyst. Guilio Natta's
`major contribution [7] was the use of the Ziegler catalyst, namely TiC14-AlEt3 , for the
`isospecific polymerization of propylene in 1954 and the resulting family of catalysts are
`now collectively called the Ziegler-Natta catalysts. Stereoregularity is an important prac(cid:173)
`tical property in the polymerization of vinyl monomers, CH2=CHR, which is capable of
`yielding polymers that are atactic, characterized by a random arrangement of R; isotactic,
`characterized by an arrangement of R uniformly on one side of the polymer backbone;
`and syndiotactic, characterized by an arrangement of R on alternate side of the polymer
`backbone plane.
`The second-generation MgC12 and/or donor-supported Ziegler-Natta catalyst system,
`which was at least 100 times more active, led to the development of the low-pressure
`polymerization processes for polyolefins and synthetic elastomers. This revolutionary de(cid:173)
`velopment resulted in the simplified gas phase low-pressure polymerization plant operation
`without the need for the removal of residual trace catalyst from the polymer, making
`nonpelletized PE and PP the industry standard. Simonazzi et al. [8] provided an impressive
`array of the accomplishments in the science, engineering, and technology of the Ziegler(cid:173)
`Natta catalysis since its discovery. Although the review sought to highlight the significant
`role of the Montecatini Research Center (now Mantell), it does provide an insight into the
`worldwide effort as it relates to the simplification of the polyolefin process technologies
`in terms of economics, versatility, safety, and environmental efficiency.
`Basically, both the heterogeneous transition metal halide and oxides catalyst systems
`are characterized by the following common features: (1) a solid surface for monomer
`adsorption; (2) a transition metal that is easily converted from one to the other of its
`several valence states; and (3) a propensity for the formation of organometallic compound
`with another organometallic or a monomer. Stereospecific polymerization of butene-1 or
`propylene (small, nonpolar, volatile monomers) requires the presence of a strong com(cid:173)
`plexing active center adsorbed on a solid surface [9-12].
`This chapter is devoted principally to the conventional polyolefins prepared with the
`following conventional catalyst systems: (1) free radical polymerization catalysts such as
`peroxides and peroxyesters; (2) anionic coordinated chromium-based Phillips catalysts;
`and (3) anionic coordinated transition metal compounds/aluminum alkyl-based Ziegler(cid:173)
`Natta catalyst systems. The global annual market size is 6000 tons for free radical initi(cid:173)
`ators, 5000 tons for Phillips catalysts, and 1500 tons for Ziegler-Natta catalysts. However,
`more than 60% of the global polyolefin production is due to the Ziegler-Natta catalyst
`systems [2].
`
`II. POLYMER FORMATION
`
`The 1933 ICI method [3] was a free radical polymerization process that includes the
`following reaction steps: initiation, propagation, termination, and chain transfer. Chain
`transfer incorporates disproportionation, hydrogen abstraction, scission reactions, and in(cid:173)
`termolecular as well as intramolecular hydrogen transfer. The ionic polymerization pro(cid:173)
`cesses of the transition metal halides and the transition metal oxide catalysts also involve
`
`PAGE 17 OF 71
`
`

`

`Conventional Polyolefins
`
`3
`
`initiation, propagation, and termination steps. In the production of linear polyethylenes,
`the reactivity of the commercially significant ionic polymerization catalysts decrease in
`the order Ti > Cr > V, whereas in propylene copolymerization the reactivity of the catalysts
`decreases in the order V > Cr > Ti. Overall, the most crucial differences could be found
`in the microstructure of the polymers resulting from each of the catalysts. For example,
`titanium-based catalyst normally yields narrow molecular weight and/or comonomer dis(cid:173)
`tributions, compared to the vanadium- and chromium-based catalysts, which yield inter(cid:173)
`mediate or broad distributions.
`The ionic polymerization catalysts could be homogeneous or heterogeneous. A typ(cid:173)
`ical heterogeneous olefin polymerization catalyst system may consist of (1) a support, (2)
`a surface-modifying reductant such as trialkylaluminum, (3) a catalyst precursor, and (4)
`a cocatalyst that activates the catalyst. The order of addition of components has an effect
`on the overall nature of the catalyst system. The support normally has to be pretreated
`either by physical dehydroxylation (calcination), chemical dehydroxylation, thermal de(cid:173)
`gassing, or surface modification using a reductant [13]. The factors affecting the overall
`performance of a supported catalyst include (1) dispersion of the catalyst precursor, (2)
`transformation characteristics during support pretreatment, (3) interaction of the catalyst
`precursor with the support, (4) possible agglomeration of the catalyst precursor, and (5)
`catalyst impurities and poisoning. An important element of catalyst design is the prevention
`of dangerous runaway reactions, particularly in gas phase polymerization where explosion
`could be especially devastating.
`
`A. Ziegler-Nata Catalyst Systems
`The Ziegler-Natta [6,7] catalyst system consists of two components that are schematically
`represented below. The transition metal compound is customarily called the catalyst and
`the alkylaluminum compound the cocatalyst. Some typical examples of these compounds
`are presented in Table 1.
`
`Catalyst:
`X
`X
`"-./
`Tm
`/"'-
`X
`X
`• Cocatalyst:
`R-Al-R
`I
`R
`
`where Tm is a transition metal from group IV to VIII; Ti, V, Zr, and Hf are normally used
`but metal carbonyls of low valency states transition metals, such as Mn and Fe, have been
`used in cocrystallization with titanium compounds [14]. X is chlorine or other halogen;
`Al is aluminum; and R is an alkyl group.
`The reactions of the various catalysts and cocatalysts have been studied extensively
`and the product derived from the reaction between, for example, TiCl4 and AlEt3 is known
`to consist of a partial colloidal mixture of the titanium halides at various oxidation states
`[8]. No complex compound was found that includes the two metal atoms such as titanium
`and aluminum [9-12,15]. The preferred Ziegler-Natta titanium catalyst compounds are
`the high-surface-area violet crystalline forms of TiCl3 and the commercially utilized tita(cid:173)
`nium trichlorides are normally activated by hydrogen or by organometallic compounds
`such as organoaluminum, organozinc, or organomagnesium compounds. Complete reduc-
`
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`

`4
`
`Olabisi
`
`Table 1 Examples of Two-Component Ziegler-Natta Catalyst Systems
`
`Transition metal salt
`
`Organometallic compounds
`
`TiC!,
`Zr(OC,H7),
`Zr[OCHEt2 ] 4
`VCI,
`V(acac),"
`Cr(acac)3"
`CoCl2 • 2 pyridine
`Zr(OC3H7)4
`Zr[OCHEt2 ],
`TiC!,
`TiC!,
`Cp2bTiClz
`TiC!,, VC!,, or TiC!,
`TiC!,, VCI,, or TiC!,
`TiC!,, VCI,, or TiCl3
`TiC!,, VC13 , or TiC!,
`TiC!,, VCI3 , or TiC!,
`TiC!,, VC13 , or TiC!,
`
`Et3Al
`Et,Al
`Et,Al
`Et2A1Cl
`Et2A1Cl
`Et2A1Cl
`Et2A1Cl
`Et2A1Cl
`Et2A1Cl
`BuLi
`BuzMg
`EtAlClz
`Et2A1Cl
`(i-C,.H,)xAly ( CsH wV
`Et,Al2Cl,
`Et,Al
`(i-C,.H9) 3Al
`(i-C4H 9)zAlH
`
`DEAC
`Isoprenyl
`EASCd
`TEAL
`TIBAL
`DIBAL-
`
`"acac,. acetylacetonate anion.
`bCp2, cyclopentadienyl.
`cWhere z = 2x, made by reacting TIBAL or DIBAL-H with isoprene.
`'Ethyl aluminum sesquichloride; Zr(OC,H7) 4 and Zr[OCH(CH,CH3),] 4 react with
`Et,AI and Et2AICI.
`Source: Refs. 8, 74-76.
`
`tion of TiCI4 to TiCl3 could be accomplished with EtAlCl2 or Et2A1Cl at 1:1 or 2:1 ratios,
`respectively [16-19].
`The activity and yield of the catalyst largely depends on the nature of the cocatalyst
`(activator) and on the catalyst/cocatalyst ratio. The effects of additional organic adjuncts
`attached to the aluminum cocatalyst underscore the fact that the activity of a catalyst
`system depends strongly on the cocatalyst type [20-23]. Dual functional titanium catalysts
`and benzyl derivatives of titanium, which are active in the absence of aluminum trialkyl,
`also exist [24-26].
`A variety of Ziegler-Natta catalysts, based on zirconium and vanadium, are as fol(cid:173)
`lows: (1) Zr(OC,H7)4 and Zr[OCH(CH2CH3) 2 ] 4; (2) Zr(OC4H 9) 2Clz, Zr(OC6H13) 2Clz,
`Zr(OC8H 17)2Cl2 ; (3) VCl3 [26], VCI4 [28,29], VCl3(THF)3 [29,30]; (4) VOCl3 [31-34],
`V0(0Bu)3 [35], and VO(OC,H5) 3; (5) vanadyl acetate [36]; and (6) mixtures. Unlike ti(cid:173)
`tanium or the other transition metal catalysts, vanadium catalysts need promoters such as
`chloroform [27,30], Freon-11 [29], dichloromethane or methylene dichloride [29-31],
`trichlorofluoromethane [27,29,30], 1,1,1-trichloroethane [27,29,39], hexachloropropane,
`heptachloropropane, or octachloropropane [37]. Because of the structural and chemical
`homogeneity of its active center, the homogeneous vanadium-based catalysts are tradi(cid:173)
`tionally used for the production of ethylene-propylene rubber (EPR) copolymer and eth(cid:173)
`ylene-propylene-diene monomer (EPDM) terpolymers. The preferred cocatalyst is halo(cid:173)
`genated aluminum alkyls and the preferred promoters include ethyl trichloroacetate,
`n-butyl perchlorocrotonate, and benzotrichloride. In the production of LLDPE, silica-sup(cid:173)
`ported vanadium catalysts are particularly active in the presence of halocarbon promoters
`
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`

`Conventional Polyolefins
`
`5
`
`resulting in a higher ~-olefin comonomer incorporation rate and better comonomer distri(cid:173)
`bution along the polymer chain. However, the vanadium-based catalysts are less capable
`of effecting a strong control over the molecular weight distribution yielding intermediate
`or broad molecular weight distribution compared with those based on titanium, zirconium,
`or hafnium. Calcium carbonate-mixed silica support could also be used for the vanadium
`based catalysts.
`Several methods exist for the preparation of the varieties of supported Ziegler-Natta
`catalysts. Some of these are impregnation, milling, comilling [38], or solution methods.
`Cocrystallization using low-valency transition metal carbonyls [14] such as Mn2(C0)10,
`Mn(C0)5Cl, V(C0)6 , and Fe(C0)8 result in solid solutions, such as FeC12 • 2TiCl3 and
`'MnC12 ·2TiCl3, which are known to be quite active. Dialkyl magnesium compounds have
`also been used as reducing agents and include the following: dimethyl magnesium, diethyl
`magnesium, di-n-butyl magnesium, n-butyl-s-butyl magnesium, ethyl-n-butyl magnesium,
`ethyl-n-hexyl magnesium, dihexyl magnesium, and butyloctyl magnesium [14,17,18,22].
`Metal chloride reducing agents, such as SiC14 [39] and BC13 [23,40], have also been used.
`Generally, the most active catalyst is based on titanium, and the high-activity, high(cid:173)
`yield MgC12-supported titanium chloride catalyst is produced either by dry comilling of
`MgC12 and titanium halides or by cocondensing MgCI, vapor with the vaporized toluene/
`TiCl4 or heptane/TiC14 or diisopropylbenzene/TiCl4 substrates [20] or by solution. The
`solubility of MgCl2 in the electron donor solvent, such as tetrahydrofuran (THF), increases
`in the presence of the reducing Lewis acid such as aluminum chloride, ethyl aluminum,
`and boron trichloride. This enables a good technique for activating the magnesium
`halide-based titanium or vanadium catalysts [40]. However, the catalyst reactivity and
`stereospecificity of the MgC12-supported titanium chloride is related to the structure of~­
`TiC13, -y-TiCl3 and o-TiCl3 vis-a-vis that of the MgC12 support [8]. The crystalline layer
`structure of the violet TiCl3 is similar to that of MgC12 and dry comilling of the two results
`in favorable epitaxial placement of the active dimeric titanium chloride on the (100) lateral
`planes of MgC12 exposing a larger number of stereospecific sites, and hence the propa(cid:173)
`gation rate. While the lateral (100) surfaces are known to be stereospecific, the (110)
`planes are known to be aspecific.
`In addition, the chemical nature and porosity of the MgC12 are said to play more
`effective roles than the specific surface area [19,42]. Indeed, complexes containing titanium
`and magnesium bonded by double-chloride bridges have been observed, exposing the tita(cid:173)
`nium atoms on the catalyst surface where they are more accessible [8]. Silica, silica-alumina,
`modified or unmodified, as well as MgO supports have been used with mixed results
`[16,18,19,22,38,40,43-45]. Catalyst modifiers such as NdCl3 , BaC12 , ZnCI,, ZnEt2 , and Gri(cid:173)
`gnard reagents (C6H 5MgCl) have been used. Magnesium alkoxides modifiers that have been
`used include magnesium methoxide and magnesium ethoxide [16,38,43,46-49]. For the
`MgCl:z/TiXJAl(iBu)3 system, the nonchloride ligands impart decreased activities although
`the resulting polyolefins might have improved properties [50]. With nonchloride ligands, the
`activity of the titanium-based catalysts increases with the decreasing electron-releasing ca(cid:173)
`pability of the ligand [51] in the following order: Ti(OC6H 5) 4 > Ti(O(CH2) 3CH3) 4 >
`Ti(N(CzH5) 2) 4 • This is further illustrated by another study where the catalyst activity is in
`accordance with the following order [52]: TiC14 > TiP2(0Bu)2 > TiCl(OBu)3 •
`The high-yield, high-stereospecificity MgC12 donor-supported tit