Principles of Polymer Processing E-Book

Zehev Tadmor

• Herausgeber: John Wiley & Sons
• Kategorie: Fachliteratur
• Sprache: Englisch

Seitenzahl: 1555

Veröffentlichungsjahr: 2008

Beschreibung

Thoroughly revised edition of the classic text on polymer processing The Second Edition brings the classic text on polymer processing thoroughly up to date with the latest fundamental developments in polymer processing, while retaining the critically acclaimed approach of the First Edition. Readers are provided with the complete panorama of polymer processing, starting with fundamental concepts through the latest current industry practices and future directions. All the chapters have been revised and updated, and four new chapters have been added to introduce the latest developments. Readers familiar with the First Edition will discover a host of new material, including: * Blend and alloy microstructuring * Twin screw-based melting and chaotic mixing mechanisms * Reactive processing * Devolatilization--theory, mechanisms, and industrial practice * Compounding--theory and industrial practice * The increasingly important role of computational fluid mechanics * A systematic approach to machine configuration design The Second Edition expands on the unique approach that distinguishes it from comparative texts. Rather than focus on specific processing methods, the authors assert that polymers have a similar experience in any processing machine and that these experiences can be described by a set of elementary processing steps that prepare the polymer for any of the shaping methods. On the other hand, the authors do emphasize the unique features of particular polymer processing methods and machines, including the particular elementary step and shaping mechanisms and geometrical solutions. Replete with problem sets and a solutions manual for instructors, this textbook is recommended for undergraduate and graduate students in chemical engineering and polymer and materials engineering and science. It will also prove invaluable for industry professionals as a fundamental polymer processing analysis and synthesis reference.

Leseprobe

Contents

Cover

Half Title page

Title page

Copyright page

Series Preface

Preface to the Second Edition

Preface to the First Edition

Chapter 1: History, Structural Formulation of the Field Through Elementary Steps, and Future Perspectives

1.1 Historical Notes

1.2 Current Polymer Processing Practice

1.3 Analysis of Polymer Processing in Terms of Elementary Steps and Shaping Methods

1.4 Future Perspectives: From Polymer Processing to Macromolecular Engineering

References

Chapter 2: The Balance Equations and Newtonian Fluid Dynamics

2.1 Introduction

2.2 The Balance Equations

2.3 Reynolds Transport Theorem

2.4 The Macroscopic Mass Balance and the Equation of Continuity

2.5 The Macroscopic Linear Momentum Balance and the Equation of Motion

2.6 The Stress Tensor

2.7 The Rate of Strain Tensor

2.8 Newtonian Fluids

2.9 The Macroscopic Energy Balance and the Bernoulli and Thermal Energy Equations

2.10 Mass Transport in Binary Mixtures and the Diffusion Equation

2.11 Mathematical Modeling, Common Boundary Conditions, Common Simplifying Assumptions, and the Lubrication Approximation

References

Problems

Chapter 3: Polymer Rheology and Non-Newtonian Fluid Mechanics

3.1 Rheological Behavior, Rheometry, and Rheological Material Functions of Polymer Melts

3.2 Experimental Determination of the Viscosity and Normal Stress Difference Coefficients

3.3 Polymer Melt Constitutive Equations Based on Continuum Mechanics

3.4 Polymer Melt Constitutive Equations Based on Molecular Theories

References

Problems

Chapter 4: The Handling and Transporting of Polymer Particulate Solids

4.1 Some Unique Properties of Particulate Solids

4.2 Agglomeration

4.3 Pressure Distribution in Bins and Hoppers

4.4 Flow and Flow Instabilities in Hoppers

4.5 Compaction

4.6 Flow in Closed Conduits

4.7 Mechanical Displacement Flow

4.8 Steady Mechanical Displacement Flow Aided by Drag

4.9 Steady Drag-induced Flow in Straight Channels

4.10 The Discrete Element Method

References

Problems

Chapter 5: Melting

5.1 Classification and Discussion of Melting Mechanisms

5.2 Geometry, Boundary Conditions, and Physical Properties in Melting

5.3 Conduction Melting without Melt Removal

5.4 Moving Heat Sources

5.5 Sintering

5.6 Conduction Melting with Forced Melt Removal

5.7 Drag-induced Melt Removal

5.8 Pressure-induced Melt Removal

5.9 Deformation Melting

References

Problems

Chapter 6: Pressurization and Pumping

6.1 Classification of Pressurization Methods

6.2 Synthesis of Pumping Machines from Basic Principles

6.3 The Single Screw Extruder Pump

6.4 Knife and Roll Coating, Calenders, and Roll Mills

6.5 The Normal Stress Pump

6.6 The Co-rotating Disk Pump

6.7 Positive Displacement Pumps

6.8 Twin Screw Extruder Pumps

References

Problems

Chapter 7: Mixing

7.1 Basic Concepts and Mixing Mechanisms

7.2 Mixing Equipment and Operations of Multicomponent and Multiphase Systems

7.3 Distribution Functions

7.4 Characterization of Mixtures

7.5 Computational Analysis

References

Problems

Chapter 8: Devolatilization

8.1 Introduction

8.2 Devolatilization Equipment

8.3 Devolatilization Mechanisms

8.4 Thermodynamic Considerations of Devolatilization

8.5 Diffusivity of Low Molecular Weight Components in Molten Polymers

8.6 Boiling Phenomena: Nucleation

8.7 Boiling-Foaming Mechanisms of Polymeric Melts

8.8 Ultrasound-enhanced Devolatilization

8.9 Bubble Growth

8.10 Bubble Dynamics and Mass Transfer in Shear Flow

8.11 Scanning Electron Microscopy Studies of Polymer Melt Devolatilization

References

Problems

Chapter 9: Single Rotor Machines

9.1 Modeling of Processing Machines Using Elementary Steps

9.2 The Single Screw Melt Extrusion Process

9.3 The Single Screw Plasticating Extrusion Process

9.4 The Co-rotating Disk Plasticating Processor

References

Problems

Chapter 10: Twin Screw and Twin Rotor Processing Equipment

10.1 Types of Twin Screw and Twin Rotor-based Machines

10.2 Counterrotating Twin Screw and Twin Rotor Machines

10.3 Co-rotating, Fully Intermeshing Twin Screw Extruders

References

Problems

Chapter 11: Reactive Polymer Processing and Compounding

11.1 Classes of Polymer Chain Modification Reactions, Carried out in Reactive Polymer Processing Equipment

11.2 Reactor Classification

11.3 Mixing Considerations in Multicomponent Miscible Reactive Polymer Processing Systems

11.4 Reactive Processing of Multicomponent Immiscible and Compatibilized Immiscible Polymer Systems

11.5 Polymer Compounding

References

Problems

Chapter 12: Die Forming

12.1 Capillary How

12.2 Elastic Effects in Capillary Flows

12.3 Sheet Forming and Film Casting

12.4 Tube, Blown Film, and Parison Forming

12.5 Wire Coating

12.6 Profile Extrusion

References

Problems

Chapter 13: Molding

13.1 Injection Molding

13.2 Reactive Injection Molding

13.3 Compression Molding

References

Problems

Chapter 14: Stretch Shaping

14.1 Fiber Spinning

14.2 Film Blowing

14.3 Blow Molding

References

Problems

Chapter 15: Calendering

15.1 The Calendering Process

15.2 Mathematical Modeling of Calendering

15.3 Analysis of Calendering Using FEM

References

Problems

Appendix A: Rheological and Thermophysical Properties of Polymers

Acknowledgments

Experimental Results and Power Law, Carreau, and Cross Models Curve Fits

Appendix B: Conversion Tables to the International System of Units (SI)

Appendix C: Notation

Author Index

Subject Index

PRINCIPLES OF POLYMER PROCESSING

Regarding the cover: The five bubbles contain images that represent the five elementary steps of polymer processing. The bottom image is a picture of the Thomas Hancock masticator, the first documented processing machine, developed in 1820. This image was originally published in the book Thomas Hancock: Personal Narrative of the Origin and Progress of the Caoutchouc or India-Rubber Manufacture in England (London: Longman, Brown, Green, Longmans, & Roberts, 1857).

Copyright © 2006 by John Wiley & Sons, Inc. All rights reserved

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Library of Congress Cataloging-in-Publication Data:

Tadmor, Zehev, 1937-  Principles of polymer processing/Zehev Tadmor, Costas G. Gogos. − 2nd ed.     p. cm.  Includes index.  ISBN 0-471-38770-3 (cloth)  1. Polymers. 2. Polymerization. I. Gogos, Costas G. II. Title.  TP1087.T32 2006  668.9–dc22  2006009306

Series Preface

The Society of Plastics Engineers is pleased to sponsor and endorse the second edition of Principles of Polymer Processing by Zehev Tadmor and Costas Gogos. This volume is an excellent source and reference guide for practicing engineers and scientists as well as students involved in plastics processing and engineering. The authors’ writing style and knowledge of the subject matter have resulted in an enjoyable and thoughtful presentation, allowing the reader to gain meaningful insights into the subject.

SPE, through its Technical Volumes Committee, has long sponsored books on various aspects of plastics. Its involvement has ranged from identification of needed volumes and recruitment of authors to peer review and approval of new books. Technical competence pervades all SPE activities, from sponsoring new technical volumes to producing technical conferences and educational seminars. In addition, the Society publishes periodicals, including Plastics Engineering, Polymer Engineering and Science, and The Journal of Vinyl and Additive Technology.

The resourcefulness of some 20,000 practicing engineers, scientists, and technologists has made SPE the largest organization of its type worldwide. Further information is available from the Society of Plastics Engineers, 14 Fairfield Drive, Brookfield, Connecticut 06804 or at www.4spe.org.

Susan E. OderwaldExecutive DirectorSociety of Plastics Engineers

Preface to the Second Edition

Tremendous science and engineering progress has been made in polymer processing since the publication of the First Edition in 1979. Evolution in the field reflects the formidable contributions of both industrial and academic investigators, and the groundbreaking developments in rheology, polymer chemistry, polymer physics, life sciences and nano-materials, in instrumentation and improved machinery. The emerging disciplines of computational fluid mechanics and molecular modeling, aided by exponentially expanding computing power are also part of this evolution.

As discussed in Chapter 1 of this Second Edition, polymer processing is rapidly evolving into a multidisciplinary field. The aim is not only to analyze the complex thermo-mechanical phenomena taking place in polymer processing equipment, per se, but to quantitatively account for the consequences, on the fabricated polymer products. Thus, the focus of future polymer processing science will shift away from the machine, and more on the product, although the intimate material-machine interactions in the former are needed for the latter.

Consequently, this edition contains not only updated material but also a significant restructuring of the original treatment of polymer processing. First, we deleted Part I which discussed polymer structure and properties, since the subject is thoroughly covered in many classic and other texts. Second, in light of the important technological developments in polymer blends and reactive processing, new chapters on Devolatilization, Compounding and Reactive Processing, and Twin Screw and Twin Rotor-based Processing Equipment are introduced. These processes are widely used because of their unique abilities to affect rapid and efficient solid deformation melting and chaotic mixing.

However, the basic philosophy we advocated in the First Edition, which was to analyze polymer processing operations in terms of elementary and shaping steps, which are common to all such processing operations, and thereby unifying the field is retained. We have continued our attempt to answer not only “how” the machines and processes work, but also “why” they are best carried out using a specific machine or a particular process. In fact, we believe that this approach has contributed to the fundamental understanding and development of polymer processing in the last quarter-century, and to the change of focus from the machine to the quantitative prediction of product properties.

As with the First Edition, this volume is written both as a textbook for graduate and undergraduate students, as well as resource for practicing engineers and scientists. Normally, a two-semester course in needed to cover the material in the text. However for students who are familiar with fluid mechanics, heat transfer and rheology, it is possible to cover the material in one semester.

To enhance the usefulness of the Second Edition for both students and practitioners of the field, an extensive Appendix of rheological and thermo-mechanical properties of commercial polymers, prepared and assembled by Dr. Victor Tan, and for teachers, a complete problem Solution Manual, prepared by Dr. Dongyun Ren are included. For all it is hoped that this Second Edition, like the First, proves to be a useful professional “companion”.

We would like to acknowledge, with gratitude, the role and help of many: foremost, the invaluable assistance of Dr. Dongyun Ren, who spent almost three years with us at the Technion and NJIT/PPI, assisting with many aspects of the text preparation, as well as the Solution Manual; and Dr. Victor Tan, whose expert and meticulous work in measuring and gathering rheological and thermo-mechanical polymer properties provides the data needed to work out real problems. In addition, we wish to thank our colleagures, and students, who have influenced this book with their advice, criticism, comments, and conversations. Among them are David Todd, Marino Xanthos, Ica Manas-Zloczower, Donald Sebastian, Kun Hyun, Han Meijer, Jean-Francois Agassant, Dan Edie, John Vlachopoulos, Musa Kamal, Phil Coates, Mort Denn, Gerhard Fritz, Chris Macosko, Mike Jaffe, Bob Westover, Tom McLeish, Greg Rutledge, Brian Qian, Myung-Ho Kim, Subir Dey, Jason Guo, Linjie Zhu and Ming Wan Young. Special thanks are due to R. Byron Bird for his advice and whose classic approach to Transport Phenomena, inspired our approach to polymer processing as manifested in this book.

There are others we wish to mention and recall. While they are no longer with us, their work, ideas, and scientific legacy resurface on the pages of this book. Among them: Joe Biesenberger, Luigi Pollara, Peter Hold, Ally Kaufmann, Arthur Lodge, Don Marshall, Imrich Klein, Bruce Maddock, and Lew Erwin.

We wish to thank our editor, Amy Byers, our production editor, Kristen Parrish, the copy editor Trumbull Rogers, and the cover designer Mike Rutkowski. We give special thanks to Abbie Rosner for her excellent editing of our book and to Mariann Pappagallo and Rebecca Best for their administrative support.

Finally, we thank our families, who in many respects paid the price of our lengthy preoccupation with this book at the expense of time that justly belonged to them.

ZEHEV TADMORCOSTAS G. GOGOS

Haifa, IsraelNewark, New JerseyMay 2006

Preface to the First Edition

This book deals with polymer processing, which is the manufacturing activity of converting raw polymeric materials into finished products of desirable shape and properties.

Our goal is to define and formulate a coherent, comprehensive, and functionally useful engineering analysis of polymer processing, one that examines the field in an integral, not a fragmented fashion. Traditionally, polymer processing has been analysed in terms of specific processing methods such as extrusion, injection molding calendering, and so on. Our approach is to claim that what is happening to the polymer in a certain type of machine is not unique: polymers go through similar experiences in other processing machines, and these experiences can be described by a set of elementary processing steps that prepare the polymer for any of the shaping methods available to these materials. On the other hand, we emphasize the unique features of particular polymer processing methods or machines, which consist of the particular elementary step and shaping mechanisms and geometrical solutions utilized.

Because with the approach just described we attempt to answer questions not only of “how” a particular machine works but also “why” a particular design solution is the “best” among those conceptually available, we hope that besides being useful for students and practicing polymer engineers and scientists, this book can also serve as a tool in the process of creative design.

The introductory chapter highlights the technological aspects of the important polymer processing methods as well as the essential features of our analysis of the subject. Parts I and II deal with the fundamentals of polymer science and engineering that are necessary for the engineering analysis of polymer processing. Special emphasis is given to the “structuring” effects of processing on polymer morphology and properties, which constitute the “meeting ground” between polymer engineering and polymer science. In all the chapters of these two parts, the presentation is utilitarian; that is, it is limited to what is necessary to understand the material that follows.

Part III deals with the elementary processing steps. These “steps” taken together make up the total thermomechanical experience that a polymer may have in any polymer processing machine prior to shaping. Examining these steps separately, free from any particular processing method, enables us to discuss and understand the range of the mechanisms and geometries (design solutions) that are available. Part III concludes with a chapter on the modeling of the single-screw extruder, demonstrating the analysis of a complete processor in terms of the elementary steps. We also deal with a new polymer processing device to demonstrate that synthesis (invention) is also facilitated by the elementary-step approach.

We conclude the text with the discussion of the classes of shaping methods available to polymers. Again, each of these shaping methods is essentially treated independently of any particular processing method. In addition to classifying the shaping methods in a logical fashion, we discuss the “structuring” effects of processing that arise because the macromolecular orientation occurring during shaping is fixed by rapid solidification.

The last chapter, a guide to the reader for the analysis of any of the major processing methods in terms of the elementary steps, is necessary because of the unconventional approach we adopt in this book.

For engineering and polymer science students, the book should be useful as a text in either one-semester or two-semester courses in polymer processing. The selection and sequence of material would of course be very much up to the instructor, but the following syllabi are suggested: For a one-semester course: Chapter 1; Sections 5.2, 4, and 5; Chapter 6; Sections 7.1, 2, 7, 9, and 10; Sections 9.1, 2, 3, 7, and 8; Chapter 10; Section 12.1; Sections 13.1, 2, 4, and 5; Section 14.1; Section 15.2; and Chapter 17—students should be asked to review Chapters 2, 3, and 4, and for polymer science students the course content would need to be modified by expanding the discussion on transport phenomena, solving the transport methodology problems, and deleting Sections 7.7, 9, and 10. For a two-semester course: in the first semester, Chapters 1, 5, and 6; Sections 7.1, 2, and 7 to 13; Sections 8.1 to 4, and 7 to 13; Chapters 9 and 10; and Sections 11.1 to 4, 6, 8, and 10—students should be asked to review Chapters 2, 3, and 4; and in the second semester, Chapters 12 and 13; Section 14.1, and Chapters 15, 16, and 17.

The problems included at the end of Chapters 5 to 16 provide exercises for the material discussed in the text and demonstrate the applicability of the concepts presented in solving problems not discussed in the book.

We acknowledge with pleasure the colleagues who helped us in our efforts. Foremost, we thank Professor J. L. White of the University of Tennessee, who reviewed the entire manuscript and provided invaluable help and advice on both the content and the structure of the book. We further acknowledge the constructive discussions and suggestions offered by Professors R. B. Bird and A. S. Lodge (University of Wisconsin), J. Vlachopoulos (McMaster University), A. Rudin (University of Waterloo), W. W. Graessley (Northwestern University), C. W. Macosko (University of Minnesota), R. Shinnar (CUNY), R. D. Andrews and J. A. Biesenberger (Stevens Institute), W. Resnick, A. Nir, A. Ram, and M. Narkis (Technion), Mr. S. J. Jakopin (Werner-Pfleiderer Co.), and Mr. W. L. Krueger (3M Co.). Special thanks go to Dr. P. Hold (Farrel Co.), for the numerous constructive discussions and the many valuable comments and suggestions. We also thank Mr. W. Rahim (Stevens), who measured the rheological and thermophysical properties that appear in Appendix A, and Dr. K. F. Wissbrun (Celanese Co.), who helped us with the rheological data and measured η0. Our graduate students of the Technion and Stevens Chemical Engineering Departments deserve special mention, because their response and comments affected the form of the book in many ways.

We express our thanks to Ms. D. Higgins and Ms. L. Sasso (Stevens) and Ms. N. Jacobs (Technion) for typing and retyping the lengthy manuscript, as well as to Ms. R. Prizgintas who prepared many of the figures. We also thanks Brenda B. Griffing for her thorough editing of the manuscript, which contributed greatly to the final quality of the book.

This book would not have been possible without the help and support of Professor J. A. Biesenberger and Provost L. Z. Pollara (Stevens) and Professors W. Resnick, S. Sideman, and A. Ram (Technion).

Finally, we thank our families, whose understanding, support, and patience helped us throughout this work.

ZEHEV TADMORCOSTAS G. GOGOS

Haifa, IsraelHoboken, New JerseyMarch 1978

*R. B. Bird, W. E. Stewart, and E. N. Lightfoot, Transport Phenomena, Wiley, New York, 1960; and R. B. Bird, R. C. Armstrong, and O. Hassager, Dynamics of Polymeric Liquids, Wiley, New York, 1977.

Chapter 1

History, Structural Formulation of the Field Through Elementary Steps, and Future Perspectives

1.1 Historical Notes

1.2 Current Polymer Processing Practice

1.3 Analysis of Polymer Processing in Terms of Elementary Steps and Shaping Methods

1.4 Future Perspectives: From Polymer Processing to Macromolecular Engineering

Polymer processing is defined as the “engineering activity concerned with operations carried out on polymeric materials or systems to increase their utility” (1). Primarily, it deals with the conversion of raw polymeric materials into finished products, involving not only shaping but also compounding and chemical reactions leading to macromolecular modifications and morphology stabilization, and thus, “value-added” structures. This chapter briefly reviews the origins of current polymer processing practices and introduces the reader to what we believe to be a rational and unifying framework for analyzing polymer processing methods and processes. The chapter closes with a commentary on the future of the field, which is currently being shaped by the demands of predicting, a priori, the final properties of processed polymers or polymer-based materials via simulation, based on first molecular principles and multiscale examination (2).

1.1 HISTORICAL NOTES

Plastics and Rubber Machinery

Modern polymer processing methods and machines are rooted in the 19th-century rubber industry and the processing of natural rubber. The earliest documented example of a rubber-processing machine is a rubber masticator consisting of a toothed rotor turned by a winch inside a toothed cylindrical cavity. Thomas Hancock developed it in 1820 in England, to reclaim scraps of processed natural rubber, and called it the “pickle” to confuse his competitors. A few years later, in 1836, Edwin Chaffee of Roxbury, Massachusetts, developed the two-roll mill for mixing additives into rubber and the four-roll calender for the continuous coating of cloth and leather by rubber; his inventions are still being used in the rubber and plastics industries. Henry Goodyear, brother of Charles Goodyear, is credited with developing the steam-heated two-roll mill (3). Henry Bewley and Richard Brooman apparently developed the first ram extruder in 1845 in England (4), which was used in wire coating. Such a ram extruder produced the first submarine cable, laid between Dover and Calais in 1851, as well as the first transatlantic cable, an Anglo-American venture, in 1860.

The need for continuous extrusion, particularly in the wire and cable field, brought about the single most important development in the processing field–the single screw extruder (SSE), which quickly replaced the noncontinuous ram extruders. Circumstantial evidence indicates that A. G. DeWolfe, in the United States, may have developed the first screw extruder in the early 1860s (5). The Phoenix Gummiwerke has published a drawing of a screw dated 1873 (6), and William Kiel and John Prior, in the United States, both claimed the development of such a machine in 1876 (7). But the birth of the extruder, which plays such a dominant role in polymer processing, is linked to the 1879 patent of Mathew Gray in England (8), which presents the first clear exposition of this type of machine. The Gray machine also included a pair of heated feeding rolls. Independent of Gray, Francis Shaw, in England, developed a screw extruder in 1879, as did John Royle in the United States in 1880.

John Wesley Hyatt invented the thermoplastics injection-molding machine in 1872 (9), which derives from metal die-casting invented and used earlier. Hyatt was a printer from Boston, who also invented Celluloid (cellulose nitrate), in response to a challenge award of $10,000 to find a replacement material for ivory used for making billiard balls. He was a pioneering figure, who contributed many additional innovations to processing, including blow molding. His inventions also helped in the quick adoption of phenol-formaldehyde (Bakelite) thermosetting resins developed by Leo Baekeland in 1906 (10). J. F. Chabot and R. A. Malloy (11) give a detailed history of the development of injection molding up to the development and the widespread adoption of the reciprocating injection molding machine in the late 1950s.

Multiple screw extruders surfaced about the same time. Paul Pfleiderer introduced the nonintermeshing, counterrotating twin screw extruder (TSE) in 1881, whereas the intermeshing variety of twin screw extruders came much later, with R. W Eastons co-rotating machine in 1916, and A. Olier’s positive displacement counterrotating machine in 1921 (12). The former led to the ZSK-type machines invented by Rudolph Erdmenger at Bayer and developed jointly with a Werner and Pfleiderer Co. team headed by Gustav Fahr and Herbert Ocker. This machine, like most other co-rotating, intermeshing TSEs, enjoys a growing popularity. They all have the advantage that the screws wipe one another, thus enabling the processing of a wide variety of polymeric materials. In addition, they incorporate “kneading blocks” for effective intensive and extensive mixing. They also generally have segmented barrels and screws, which enables the machine design to be matched to the processing needs. There is a broad variety of twin and multiple screw mixers and extruders; some of them are also used in the food industry. Hermann (12) and White (7) give thorough reviews of twin screw and multiple screw extruders and mixers.