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HANDBOOK OF POLYMERSYNTHESIS, CHARACTERIZATION,AND PROCESSING
HANDBOOK OF POLYMERSYNTHESIS, CHARACTERIZATION,AND PROCESSING
Edited by
ENRIQUE SALDıVAR-GUERRACentro de Investigacion en Quımica AplicadaSaltillo Coahuila, Mexico
EDUARDO VIVALDO-LIMAFacultad de Quımica, Universidad Nacional Autonoma de MexicoCiudad Universitaria, Mexico, D.F., Mexico
A JOHN WILEY & SONS, INC., PUBLICATION
Copyright © 2013 by John Wiley & Sons, Inc. All rights reserved
Published by John Wiley & Sons, Inc., Hoboken, New JerseyPublished simultaneously in Canada
No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical,photocopying, recording, scanning, or otherwise, except as permitted under Section 107 or 108 of the 1976 United States Copyright Act, without eitherthe prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, Inc.,222 Rosewood Drive, Danvers, MA 01923, (978) 750-8400, fax (978) 750-4470, or on the web at www.copyright.com. Requests to the Publisher forpermission should be addressed to the Permissions Department, John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, (201) 748-6011, fax(201) 748-6008, or online at http://www.wiley.com/go/permission.
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Library of Congress Cataloging-in-Publication Data:
Handbook of polymer synthesis, characterization, and processing / edited by Enrique Saldıvar-Guerra, Centro de Investigacion en Quımica Aplicada,Saltillo Coahuila, Mexico, Eduardo Vivaldo-Lima, Facultad de Quımica, Departamento de Ingenierıa Quımica, Universidad Nacional Autonoma deMexico, Mexico, D.F., Mexico.
pages cmIncludes bibliographical references and index.
ISBN 978-0-470-63032-7 (cloth)1. Polymerization. I. Saldıvar-Guerra, Enrique, editor of compilation. II. Vivaldo-Lima, Eduardo, editor of compilation.
TP156.P6H36 2013547′.28–dc23
2012025752
Printed in the United States of America
ISBN: 9780470630327
10 9 8 7 6 5 4 3 2 1
To Amparo, Adriana and Andres, with loveTo Adriana, Eduardo Abraham and Luis Angel, with appreciation and love
CONTENTS
PREFACE xv
ACKNOWLEDGMENTS xvii
CONTRIBUTORS xix
PART I BASIC CONCEPTS 1
1 Introduction to Polymers and Polymer Types 3Enrique Saldıvar-Guerra and Eduardo Vivaldo-Lima
1.1 Introduction to Polymers 31.2 Classification of Polymers 81.3 Nomenclature 12
References 13
2 Polymer States and Properties 15J. Betzabe Gonzalez-Campos, Gabriel Luna-Barcenas, Diana G. Zarate-Trivino,Arturo Mendoza-Galvan, Evgen Prokhorov, Francisco Villasenor-Ortega,and Isaac C. Sanchez
2.1 Introduction 152.2 Glass Transition Temperature (α-Relaxation) Controversy in Chitin,
Chitosan, and PVA 162.3 Glass Transition Related to the α-Relaxation 162.4 Moisture Content Effects on Polymer’s Molecular Relaxations 172.5 Dielectric Fundamentals 182.6 Chitin, Chitosan, and PVA Films Preparation for Dielectric
Measurements 212.7 Dielectric Relaxations in Chitin: Evidence for a Glass Transition 222.8 Dielectric Relaxations in Neutralized and Nonneutralized Chitosan:
The Stronger Water Content Effect on the α-Relaxation and the GlassTransition Phenomenon 30
2.9 PVA Dielectric Relaxations 35References 38
vii
viii CONTENTS
PART II POLYMER SYNTHESIS AND MODIFICATION 41
3 Step-Growth Polymerization 43Luis E. Elizalde, Gladys de los Santos-Villarreal, Jose L. Santiago-Garcıa,and Manuel Aguilar-Vega
3.1 Introduction 433.2 Polymerization Kinetics 463.3 Polyamides 483.4 Polyimides 503.5 Polyesters 503.6 Inorganic Condensation Polymers 533.7 Dendrimers 543.8 Thermoset Polycondensation Polymers 553.9 Controlled Molecular Weight Condensation Polymers 57
References 62
4 Free Radical Polymerization 65Ramiro Guerrero-Santos, Enrique Saldıvar-Guerra, and Jose Bonilla-Cruz
4.1 Introduction 654.2 Basic Mechanism 664.3 Other Free Radical Reactions 684.4 Kinetics and Polymerization Rate 714.5 Molecular Weight and Molecular Weight Distribution 744.6 Experimental Determination of Rate Constants 764.7 Thermodynamics of Polymerization 774.8 Controlled Radical Polymerization 78
References 81
5 Coordination Polymerization 85Joao B. P. Soares and Odilia Perez
5.1 Introduction 855.2 Polymer Types 875.3 Catalyst Types 875.4 Coordination Polymerization Mechanism 935.5 Polymerization Kinetics and Mathematical Modeling 93
References 101
6 Copolymerization 105Marc A. Dube, Enrique Saldıvar-Guerra, and Ivan Zapata-Gonzalez
6.1 Introduction 1056.2 Types of Copolymers 1066.3 Copolymer Composition and Microstructure 1076.4 Reaction Conditions: Considerations 118
References 121
7 Anionic Polymerization 127Roderic Quirk
7.1 Introduction 1277.2 Living Anionic Polymerization 1277.3 General Considerations 1297.4 Kinetics and Mechanism of Polymerization 134
CONTENTS ix
7.5 Stereochemistry 1447.6 Copolymerization of Styrenes and Dienes 1487.7 Synthetic Applications of Living Anionic Polymerization 150
References 157
8 Cationic Polymerizations 163Filip E. Du Prez, Eric J. Goethals, and Richard Hoogenboom
8.1 Introduction 1638.2 Carbocationic Polymerization 1638.3 Cationic Ring-Opening Polymerization 1728.4 Summary and Prospects 181
Acknowledgment 181References 181
9 Crosslinking 187Julio Cesar Hernandez-Ortiz and Eduardo Vivaldo-Lima
9.1 Introduction 1879.2 Background on Polymer Networks 1879.3 Main Chemical Routes for Synthesis of Polymer Networks 1919.4 Characterization of Polymer Networks and Gels 1939.5 Theory and Mathematical Modeling of Crosslinking 195Appendix A Calculation of Average Chain Length 200Appendix B Calculation of Sol and Gel Fractions 201
Acknowledgments 202References 202
10 Polymer Modification: Functionalization and Grafting 205Jose Bonilla-Cruz, Mariamne Dehonor, Enrique Saldıvar-Guerra, andAlfonso Gonzalez-Montiel
10.1 General Concepts 20510.2 Graft Copolymers 207
References 219
11 Polymer Additives 225Rudolf Pfaendner
11.1 Introduction 22511.2 Antioxidants 22711.3 PVC Heat Stabilizers 23111.4 Light Stabilizers 23311.5 Flame Retardants 23511.6 Plasticizers 23811.7 Scavenging Agents 23911.8 Additives to Enhance Processing 24011.9 Additives to Modify Plastic Surface Properties 24011.10 Additives to Modify Polymer Chain Structures 24111.11 Additives to Influence Morphology and Crystallinity
of Polymers 24211.12 Antimicrobials 24311.13 Additives to Enhance Thermal Conductivity 24311.14 Active Protection Additives (Smart Additives) 24311.15 Odor Masking 244
x CONTENTS
11.16 Animal Repellents 24411.17 Markers 24411.18 Blowing Agents 24411.19 Summary and Trends in Polymer Additives 245
References 245Further Reading 246
PART III POLYMERIZATION PROCESSES AND ENGINEERING 249
12 Polymer Reaction Engineering 251Alexander Penlidis, Eduardo Vivaldo-Lima, Julio Cesar Hernandez-Ortiz,and Enrique Saldıvar-Guerra
12.1 Introduction 25112.2 Mathematical Modeling of Polymerization Processes 25212.3 Useful Tips on Polymer Reaction Engineering (PRE) and Modeling 25712.4 Examples of Several Free Radical (Co)Polymerization Schemes
and the Resulting Kinetic and Molecular Weight DevelopmentEquations 264Acknowledgments 270References 270
13 Bulk and Solution Processes 273Marco A. Villalobos and Jon Debling
13.1 Definition 27313.2 History 27313.3 Processes for Bulk and Solution Polymerization 27413.4 Energy Considerations 28713.5 Mass Considerations 289
References 292
14 Dispersed-Phase Polymerization Processes 295Jorge Herrera-Ordonez, Enrique Saldıvar-Guerra, and Eduardo Vivaldo-Lima
14.1 Introduction 29514.2 Emulsion Polymerization 29514.3 Microemulsion Polymerization 30314.4 Miniemulsion Polymerization 30414.5 Applications of Polymer Latexes 30414.6 Dispersion and Precipitation Polymerizations 30514.7 Suspension Polymerization 30514.8 Controlled Radical Polymerization (CRP) in Aqueous
Dispersions 308References 310
15 New Polymerization Processes 317Eduardo Vivaldo-Lima, Carlos Guerrero-Sanchez, Christian H. Hornung,Iraıs A. Quintero-Ortega, and Gabriel Luna-Barcenas
15.1 Introduction 31715.2 Polymerizations in Benign or Green Solvents 31715.3 Alternative Energy Sources for Polymerization Processes 32715.4 Polymerization in Microreactors 329
CONTENTS xi
Acknowledgments 331References 331
PART IV POLYMER CHARACTERIZATION 335
16 Polymer Spectroscopy and Compositional Analysis 337Gladys de los Santos-Villarreal and Luis E. Elizalde
16.1 Introduction 33716.2 Elemental Analysis 33716.3 Infrared Spectroscopy 33916.4 Nuclear Magnetic Resonance of Polymers in Solution 34316.5 Mass Spectrometry 351
References 353
17 Polymer Molecular Weight Measurement 355Marıa Guadalupe Neira-Velazquez, Marıa Teresa Rodrıguez-Hernandez,Ernesto Hernandez-Hernandez, and Antelmo R. Y. Ruiz-Martınez
17.1 Introduction 35517.2 Historical Background 35517.3 Principles of GPC 35617.4 Measurement of Intrinsic Viscosity 362
References 365
18 Light Scattering and its Applications in Polymer Characterization 367Roberto Alexander-Katz
18.1 Introduction 36718.2 Principles of Static and Dynamic Light Scattering 36718.3 Static Light Scattering by Dilute Polymer Solutions 37018.4 Dynamic Light Scattering 377
References 387
19 Small-Angle X-Ray Scattering of Polymer Systems 391Carlos A. Avila-Orta and Francisco J. Medellın-Rodrıguez
19.1 Introduction 39119.2 Polymer Morphology 39119.3 Small-Angle X-Ray Scattering 39319.4 Analysis in Reciprocal Space 39519.5 Analysis in Real Space 399Appendix A Procedure to Obtain Morphological Data from 1D SAXS
Profiles 404References 406
20 Microscopy 409Mariamne Dehonor, Carlos Lopez-Barron, and Christopher W. Macosko
20.1 Introduction 40920.2 Transmission Electron Microscopy 40920.3 Three-Dimensional Microscopy 416
References 421
xii CONTENTS
21 Structure and Mechanical Properties of Polymers 425Manuel Aguilar-Vega
21.1 Structure of Polymer Chains 42521.2 Mechanical Properties of Polymers 42621.3 Mechanical Properties of Polymer Composites 431
References 434
PART V POLYMER PROCESSING 435
22 Polymer Rheology 437Estanislao Ortız-Rodrıguez
22.1 Introduction to Polymer Rheology Fundamentals 43722.2 Linear Viscoelasticity 44022.3 Viscometric Techniques for Polymer Melts 44122.4 Overview of Constitutive Equations 44322.5 Brief Overview on Other Relevant Polymer Rheology Aspects 445
References 448
23 Principles of Polymer Processing 451Luis F. Ramos-de Valle
23.1 General 45123.2 Compounding 45123.3 Extrusion 45223.4 Bottle Blowing 45523.5 Injection Molding 45523.6 Thermoforming 460
References 461Further Reading 461
24 Blown Films and Ribbons Extrusion 463Jorge R. Robledo-Ortız, Daniel E. Ramırez-Arreola, Denis Rodrigue,and Ruben Gonzalez-Nunez
24.1 Introduction 46324.2 Extrusion Processes for Blown Films and Ribbons 46324.3 Equations 46524.4 Ribbon and Film Dimensions 46724.5 Cooling Process and Stretching Force 46724.6 Morphology and Mechanical Properties 469
References 472
25 Polymer Solutions and Processing 473Damaso Navarro Rodrıguez
25.1 Introduction 47325.2 Polymer Solution Thermodynamics and Conformation of Polymer
Chains: Basic Concepts 47425.3 Semidilute Polymer Solutions 48125.4 Processing of Polymer Solutions 482
References 488
CONTENTS xiii
26 Wood and Natural Fiber-Based Composites (NFCs) 493Jorge R. Robledo-Ortız, Francisco J. Fuentes-Talavera, Ruben Gonzalez-Nunez,and Jose A. Silva-Guzman
26.1 Introduction 49326.2 Background 49326.3 Raw Materials 49426.4 Manufacturing Process 49726.5 Properties of Composite Materials 49726.6 Durability 49826.7 Factors that Affect Decay of Wood–Plastic Composites 50026.8 Uses of Wood–Plastic Composites 501
References 501
27 Polymer Blends 505Saul Sanchez-Valdes, Luis F. Ramos-de Valle, and Octavio Manero
27.1 Introduction 50527.2 Miscibility in Polymer Blends 50527.3 Compatibility in Polymer Blends 50827.4 Techniques for Studying Blend Microstructure 50927.5 Preparation of Polymer Blends 51027.6 Factors Influencing the Morphology of a Polymer Blend 51127.7 Properties of Polymer Blends 51327.8 Applications of Polymer Blends 516
References 517
28 Thermosetting Polymers 519Jean-Pierre Pascault and Roberto J.J. Williams
28.1 Introduction 51928.2 Chemistries of Network Formation 52028.3 Structural Transformations During Network Formation 52128.4 Processing 52428.5 Conclusions 532
References 532
PART VI POLYMERS FOR ADVANCED TECHNOLOGIES 535
29 Conducting Polymers 537Marıa Judith Percino and Vıctor Manuel Chapela
29.1 Introduction 53729.2 Historical Background 53829.3 The Structures of Conducting Polymers 53929.4 Charge Storage 53929.5 Doping 54129.6 Polyanilines 54329.7 Charge Transport 54429.8 Syntheses 54529.9 Conducting Polymers 54529.10 Characterization Techniques 55129.11 Present and Future Potential 552
References 555
xiv CONTENTS
30 Dendritic Polymers 559Jason Dockendorff and Mario Gauthier
30.1 Introduction 55930.2 Dendrimers 56130.3 Hyperbranched Polymers 56730.4 Dendrigraft Polymers 57430.5 Concluding Remarks 581
References 582
31 Polymer Nanocomposites 585Octavio Manero and Antonio Sanchez-Solis
31.1 Introduction 58531.2 Polyester/Clay Nanocomposites 58631.3 Polyolefin/Clay Nanocomposites 59031.4 Polystyrene/Clay Nanocomposites 59331.5 Polymer/Carbon Black Nanocomposites 59631.6 Nanoparticles of Barium Sulfate 59731.7 Polymer/Graphene Nanocomposites 59831.8 Conclusions 601
Acknowledgments 601References 601
INDEX 605
PREFACE
The industry of polymers is very complex, in part because itencompasses many aspects that are of multidisciplinary na-ture. The chain of production of polymers requires expertknowledge in different areas: (i) polymer synthesis, bothfrom the chemistry and the engineering aspects; (ii) poly-mer characterization, including chemical, physicochemical,rheological properties and others; and (iii) polymer process-ing and transformation into final products.
The aim of this handbook is to serve as the first sourceand comprehensive reference to all aspects of interest in thepolymer industry. Given the complexity of this industryand the specialized knowledge required in each area ofpolymer production and application, most of the booksdealing with polymer science and technology cover onlysome aspects of the polymer production chain; however, webelieve that a professional working in the polymer industryor, in general, in polymer science and technology wouldgreatly benefit from a book summarizing all the aspectsinvolved in the production chain of the polymer industry.The book has been written with the underlying idea ofmeeting this need. An effort has been made in every chapterto include the fundamentals of the chapter’s subject, therelevant literature, and the new trends in the field.
The book is addressed mainly to professionals in virtu-ally all positions in the polymer industry: manufacturing,quality control, R&D, sales, technical assistance, and so on.Another group of potential readers is the undergraduate andgraduate students in fields related to polymer science andtechnology. Finally, academic researchers of universitiesand institutes, working in different areas of polymerizationand polymers, will find the book useful for expanding theirknowledge beyond their area of expertise. The book canbe used to establish the first approach to a specific topic byanyone in the target audience, to broaden the knowledge
of industrial practitioners wanting to know more about thepolymer production chain, and to look for references inorder to deepen the understanding of specialized aspects ofa topic. It can also be used as a textbook in the first coursein polymer science or engineering, at the undergraduate orgraduate level, especially if a broad coverage of the fieldis desired.
After an introduction to the basic concepts of polymersand polymerization (Chapter 1) and thermodynamic poly-mer states (Chapter 2)1, the second part of the handbookis devoted to the main synthesis techniques of polymers(Chapters 3–5 and 7–8), including chapters covering con-cepts that may be applicable to all the synthesis techniques(crosslinking and grafting in Chapters 9 and 10, respec-tively). The important subject of copolymers (Chapter 6) isalso included in this section, as synthesis and structure areclosely related areas. The subject of additives is includedin the synthesis section because, from the point of view ofproperties and applications, they have become an importantpart of the polymeric material being synthesized. The thirdpart of the handbook is dedicated to the engineering prin-ciples and the different types of polymerization processesused in industry (Chapters 12–14); the new trends, froman engineering perspective, are also discussed (Chapter15). Part IV, which includes Chapters 16–21, provides thescope of the main techniques used for polymer characteri-zation and testing, at both the fundamental and the appliedlevels. Chapters 22–28 cover polymer processing princi-ples, techniques, and equipment. Chapter 28 (ThermosettingPolymers) is included here because of the emphasis on in-dustrial processes, although it implies simultaneous reactionand shaping. Finally, Chapters 29–31 deal with advanced
1Some important thermodynamic concepts related to polymers are dealtwith in Chapter 25.
xv
xvi PREFACE
and more specialized subjects in the polymer field, whichare of increasing importance (nanomaterials, dendrimers,and conjugated polymers).
The handbook represents the joint effort of a largenumber of scientists and researchers working in the many
diverse fields of polymer science and technology. Manyyears of study and experience have been put together inan organized manner in this work; hopefully, the handbookwill serve its purpose with a large audience.
ACKNOWLEDGMENTS
We are deeply grateful to the authors of all the chapters fortheir contribution and for sharing their expert knowledge.We also thank the Wiley-Blackwell editors and team fortheir support and guidance throughout the writing andediting of the handbook.
We also thank the several sponsors who have allowed usto carry out fundamental and applied research to an extentwhere we feel that we have added a few salt grains to thepolymer science and engineering fields. E.V.-L. is indebted
to UNAM (PAIP and PAPIIT Project 119510), CONA-CyT (Project 101682), and ICyTDF (Project PICSA11-56).E.S.-G. acknowledges CIQA and CONACyT for continu-ous support.
Last but not least, we thank our families for their supportand understanding during the editing of the handbook, andto some of our students and office staff at CIQA and FQ-UNAM for taking some extra work load that allowed us toinvest time in this project.
xvii
CONTRIBUTORS
Manuel Aguilar-Vega, Materials Unit, Membranes Labo-ratory, Centro de Investigacion Cientıfica de Yucatan,Merida, Yucatan, Mexico
Roberto Alexander-Katz, Departamento de Fısica, Uni-versidad Autonoma Metropolitana-Iztapalapa, Col. Vi-centina, Mexico
Carlos A. Avila-Orta, Centro de Investigacion en QuımicaAplicada, Saltillo, Coahuila, Mexico
Jose Bonilla-Cruz, Centro de Investigacion en MaterialesAvanzados, Apodaca, Nuevo Leon, Mexico
Vıctor Manuel Chapela, Laboratorio de Polımeros, Insti-tuto de Ciencias, Benemerita Universidad Autonoma dePuebla, Puebla, Pue., Mexico
Jon Debling, BASF Corp., Wyandotte, MI, USA
Mariamne Dehonor, Macro-M S.A. de C.V. Lerma, Edo.de Mexico, Mexico
Jason Dockendorff, Department of Chemistry, Institute forPolymer Research, University of Waterloo, Waterloo,Ontario, Canada
Filip E. Du Prez, Department of Organic Chemistry,Polymer Chemistry Research group, Ghent University,Ghent, Belgium
Marc A. Dube, Department of Chemical and Biolog-ical Engineering, Centre for Catalysis Research andInnovation, University of Ottawa, Ottawa, Ontario,Canada
Luis E. Elizalde, Centro de Investigacion en QuımicaAplicada, Saltillo, Coahuila, Mexico
Francisco J. Fuentes-Talavera, Departamento de Madera,Celulosa y Papel, Universidad de Guadalajara, LasAgujas, Zapopan, Jalisco, Mexico
Mario Gauthier, Department of Chemistry, Institute forPolymer Research, University of Waterloo, Waterloo,Ontario, Canada
Eric J. Goethals, Department of Organic Chemistry,Polymer Chemistry Research group, Ghent University,Ghent, Belgium
J. Betzabe Gonzalez-Campos, Universidad Michoacanade San Nicolas de Hidalgo, Instituto de InvestigacionesQuımico-Biologicas, Morelia, Michoacan, Mexico
Alfonso Gonzalez-Montiel, Macro M S.A. de C.V. Lerma,Edo. De Mexico, Mexico
Ruben Gonzalez-Nunez, Departamento de IngenierıaQuımica, Universidad de Guadalajara, Guadalajara,Jalisco, Mexico
Carlos Guerrero-Sanchez, CSIRO, Materials Science andEngineering Division, Victoria, Australia
Ramiro Guerrero-Santos, Centro de Investigacionen Quımica Aplicada, Saltillo, Coahuila, Mexico
Ernesto Hernandez-Hernandez, Centro de Investigacionen Quımica Aplicada, Saltillo, Coahuila, Mexico
Julio Cesar Hernandez-Ortiz, Departamento deIngenierıa Quımica, Facultad de Quımica, Univer-sidad Nacional Autonoma de Mexico, Mexico D.F.,Mexico
Jorge Herrera-Ordonez, Centro de Investigacionen Quımica Aplicada, Saltillo, Coahuila, Mexico
xix
xx CONTRIBUTORS
Richard Hoogenboom, Department of Organic Chemistry,Supramolecular Chemistry group, Ghent University,Ghent, Belgium
Christian H. Hornung, CSIRO, Materials Science andEngineering Division, Victoria, Australia
Carlos Lopez-Barron, Center for Neutron Science, De-partment of Chemical and Biomolecular Engineering,University of Delaware, Newark, DE, USA
Gabriel Luna-Barcenas, Centro de Investigacion y deEstudios Avanzados (CINVESTAV) del IPN, UnidadQueretaro, Queretaro, Queretaro, Mexico
Christopher W. Macosko, Dept. of Chemical Engineeringand Materials Science, University of Minnesota, Min-neapolis, MN, USA
Octavio Manero, Instituto de Investigaciones en Ma-teriales, Universidad Nacional Autonoma de Mexico,Mexico D.F., Mexico
Francisco J. Medellın-Rodrıguez, Facultad de CienciasQuımicas, Universidad Autonoma de San Luis Potosı,San Luis Potosı, San Luis Potosı, Mexico
Arturo Mendoza-Galvan, Centro de Investigacion y deEstudios Avanzados (CINVESTAV) del IPN, UnidadQueretaro, Queretaro, Queretaro, Mexico
Damaso Navarro Rodrıguez, Centro de Investigacion enQuımica Aplicada, Saltillo, Coahuila, Mexico
Marıa Guadalupe Neira-Velazquez, Centro de Inves-tigacion en Quımica Aplicada, Saltillo, Coahuila,Mexico
Estanislao Ortız-Rodrıguez, A. Schulman de Mexico, SanLuis Potosı, Mexico
Jean-Pierre Pascault, Universite de Lyon, UMR-CNRS 5223, INSA-Lyon, Ingenierie des MateriauxPolymeres/Laboratoire des Materiaux Macro-moleculaires, Villeurbanne, France
Alexander Penlidis, Department of Chemical Engineering,Institute for Polymer Research (IPR), University ofWaterloo, Waterloo, Ontario, Canada
Marıa Judith Percino, Laboratorio de Polımeros, Institutode Ciencias, Benemerita Universidad Autonoma dePuebla, Puebla, Pue., Mexico
Odilia Perez, Centro de Investigacion en Quımica Apli-cada, Saltillo, Coahuila, Mexico
Rudolf Pfaendner, Fraunhofer Institute for StructuralDurability and System Reliability LBF, Division Plas-tics, Darmstadt, Germany
Evgen Prokhorov, Centro de Investigacion y de EstudiosAvanzados (CINVESTAV) del IPN, Unidad Queretaro,Queretaro, Queretaro, Mexico
Iraıs A. Quintero-Ortega, Division de Ciencias eIngenierıas, Universidad de Guanajuato, Leon, Mexico
Roderic Quirk, Dept. of Polymer Science, The Universityof Akron, Akron, OH, USA
Daniel E. Ramırez-Arreola, Departamento de Ingenierıas,Universidad de Guadalajara, Autlan de Navarro, Jalisco,Mexico
Jorge R. Robledo-Ortız, Departamento de Madera, Celu-losa y Papel, Universidad de Guadalajara, Las Agujas,Zapopan, Jalisco, Mexico
Denis Rodrigue, Department of Chemical Engineeringand CERMA, Universite Laval, Quebec City, Quebec,Canada
Marıa Teresa Rodrıguez-Hernandez, Centro de Investi-gacion en Quımica Aplicada, Saltillo, Coahuila, Mexico
Antelmo R. Y. Ruiz-Martınez, Centro de Investigacion enQuımica Aplicada, Saltillo, Coahuila, Mexico
Enrique Saldıvar-Guerra, Centro de Investigacion enQuımica Aplicada, Saltillo, Coahuila, Mexico
Isaac C. Sanchez, Chemical Engineering Department, TheUniversity of Texas at Austin
Antonio Sanchez-Solis, Instituto de Investigacionesen Materiales, Universidad Nacional Autonoma deMexico, Mexico D.F., Mexico
Jose L. Santiago-Garcıa, Materials Unit, Membranes Lab-oratory, Centro de Investigacion Cientıfica de Yucatan,Merida, Yucatan, Mexico
Gladys de los Santos-Villarreal, Centro de Investigacionen Quımica Aplicada, Saltillo, Coahuila, Mexico
Jose A. Silva-Guzman, Departamento de Madera, Celulosay Papel, Universidad de Guadalajara, Las Agujas,Zapopan, Jalisco, Mexico
Joao B. P. Soares, Department of Chemical Engineering,University of Waterloo, Waterloo, Ontario, Canada
Saul Sanchez-Valdes, Centro de Investigacion en QuımicaAplicada, Saltillo, Mexico
Luis F. Ramos-de Valle, Centro de Investigacion enQuımica Aplicada, Saltillo, Mexico
Marco A. Villalobos, Cabot Corp., Billerica, MA, USA
Francisco Villasenor-Ortega, Department of BiochemicalEngineering, Instituto Tecnologico de Celaya, Celaya,Guanajuato, Mexico
Eduardo Vivaldo-Lima, Departamento de IngenierıaQuımica, Facultad de Quımica, Universidad NacionalAutonoma de Mexico, Mexico, D.F., Mexico
CONTRIBUTORS xxi
Roberto J. J. Williams, Institute of Materials Science andTechnology (INTEMA), University of Mar del Plata andNational Research Council (CONICET), Mar del Plata,Argentina
Ivan Zapata-Gonzalez, Facultad de Ciencias Quımicas,Universidad Autonoma de Coahuila, Saltillo, Coahuila,Mexico
Diana G. Zarate-Trivino, Centro de Investigacion y deEstudios Avanzados (CINVESTAV) del IPN, UnidadQueretaro, Queretaro, Queretaro, Mexico
PART I
BASIC CONCEPTS
1INTRODUCTION TO POLYMERS AND POLYMER TYPES
Enrique Saldıvar-Guerra and Eduardo Vivaldo-Lima
1.1 INTRODUCTION TO POLYMERS
1.1.1 Basic Concepts
Polymers are very large molecules, or macromolecules,formed by the union of many smaller molecules. Thesesmaller units are termed monomers before they areconverted into polymers. In fact, the word “polymer” has aGreek origin meaning “many members.” Natural polymershave been around since the early times in Planet Earth.Life itself is linked to polymers since deoxyribonucleic acid(DNA), ribonucleic acid (RNA), and proteins, which areessential to all known forms of life, are macromolecules.Cellulose, lignin, starch, and natural rubber are just afew other examples of natural polymers. Some of thesepolymers were used by early human civilizations to producesimple artifacts; for example, the play balls from naturalrubber for the ball game of several of the Mesoamericancivilizations (which contained ritual content and not onlyentertaining purposes). In the 1800s, natural polymersbegan to be chemically modified to produce many materials,such as vulcanized rubber, gun cotton, and celluloid.Although natural polymers are very important, this bookis mainly concerned with synthetic polymers, especiallyorganic synthetic polymers. The chemical reaction bywhich polymers are synthesized from monomers is termedpolymerization; however, this is a generic term, since thereare a number of chemical mechanisms involved in differentpolymerization reactions.
Synthetic polymers are relatively modern materials,since they entered into the technological and practical sceneonly in the first decades of the twentieth century. Thismakes them very different from some other materials thathave been known to humanity for centuries or millennia.
Handbook of Polymer Synthesis, Characterization, and Processing, First Edition. Edited by Enrique Saldıvar-Guerra and Eduardo Vivaldo-Lima.© 2013 John Wiley & Sons, Inc. Published 2013 by John Wiley & Sons, Inc.
Also, given the fact that synthetic polymers are created bychemical reactions, the possibilities of building differentpolymers are virtually endless, only restricted by chemicaland thermodynamic laws and by the creativity of thesynthetic polymer chemist. These endless possibilities havegiven rise to an enormous variety of synthetic polymersthat find application in almost every conceivable field ofhuman activity that deals with matter or physical objects. Inaddition, the enormous molecular structural versatility thatis derived from the rich synthetic possibilities, translatesinto materials with extremely diverse properties, andtherefore applications.
We can find polymers as components of many of theobjects that surround us, as well as in a broad diversityof applications in daily life: clothing, shoes, personal careproducts, furniture, electrical and electronic appliances,packaging, utensils, automobile parts, coatings, paints,adhesives, tires, and so on. The list is endless, and thesefew examples should provide an idea of the importance ofsynthetic polymers to modern society, in terms of both theirusefulness and the economic value that they represent.
1.1.2 History
Some synthetic polymers were inadvertently preparedsince the mid-nineteenth century by chemists working inorganic synthesis without necessarily knowing the chemicalstructure of these materials, although some of them mayhave had some intuition of the right character of thesemolecules as very large ones [1]. Only in 1920, Staudinger[2] proposed the concept of polymers as macromolecules,and this idea slowly gained acceptance among the scientificcommunity during the next decade. Some of the supporting
3
4 INTRODUCTION TO POLYMERS AND POLYMER TYPES
evidence for the macromolecular concept came frommeasurements of high molecular weight molecules inrubber using physicochemical methods. Later, around 1929,Carothers [3] started an experimental program aimed atthe synthesis of polymers of defined structures using well-known reactions of organic chemistry; this work, togetherwith the confirmation of high molecular weight moleculesby other experimental measurements (e.g., the viscosity ofpolymer solutions), helped to confirm the correctness of themacromolecular hypothesis of Staudinger. An interestingbook on the history of polymer science is that byMorawetz [4].
1.1.3 Mechanical and Rheological Properties
1.1.3.1 Mechanical Properties Long chains with highmolecular weights impart unique properties to polymers asmaterials. This can be illustrated by analyzing the changein the properties of the homologous series of the simplesthydrocarbon chains, the alkanes, which can be seen as con-stituted of ethylene repeating units (with methyl groups atthe chain ends),1 as the number of repeating units increase.At relatively low molecular weights (C6 –C10), compoundsin these series are relatively volatile liquids (gasolines). Asthe number of ethylene units increases, the compounds inthis series start to behave as waxes with low melting points.However, if the number of ethylene units exceeds some200–300, such that the molecular weight of the chains is inthe order of 5000–8000, the material starts to behave as asolid exhibiting the higher mechanical properties associatedwith a polymer (polyethylene in this case). In general,above some minimum molecular weight, polymers exhibitincreased mechanical properties and they are considered“high polymers”, alluding to their high molecular weight.
The mechanical behavior of a polymer is characterizedby stress–strain curves in which the stress (force perunit area) needed to stretch the material to a certainelongation is plotted. In order to experimentally generatethese curves, a tension stress is applied on a polymer sampleof known dimensions, which is elongated until it breaks.The elongation is expressed as a fractional or percentageincrease of the original length of the sample, which isdenominated strain, ε, and is defined as
ε = �L
L(1.1)
where L is the original length of the sample and �L isthe increase in length under the applied tension. The natureof the stress–strain curve for a given polymer defines its
1Strictly speaking, this is valid only for alkanes with a pair number ofcarbon atoms starting from butane, since ethylene has 2 C; however, thisprecision is irrelevant for this discussion (especially at high number ofcarbons).
possible use as elastomer, fiber, or thermoplastic. Figure 1.1shows the form of the stress–strain curves for these typesof polymers, and Table 1.1 shows typical values of some ofthe mechanical properties that can be defined as a functionof the stress–strain behavior.
The elastic or Young’s modulus is the initial slope of thestress–strain curve and gives a measure of the resistance todeformation of the material. The ultimate tensile strength isthe stress required to rupture the sample, and the ultimateelongation is the extent of elongation at which the ruptureof the sample occurs.
Mechanical properties are discussed here only in anintroductory manner in order to understand the mainapplications of polymers. An extended discussion of themechanical properties of polymers and their measurementcan be found in Chapter 21.
1.1.3.2 Rheological Properties Thermoplastics are pro-cessed and shaped in the molten state. This can be looselydefined as a state in which a polymer flows under the actionof heat and pressure. Molten polymers are non-Newtonianfluids, as opposed to the simpler Newtonian fluids. In thelatter, the stress σ (force per unit area) is proportional tothe shear rate γ (velocity per unit length) with a propor-tionality factor μ (viscosity) which is constant at a giventemperature. Newtonian fluids follow the law
σ = μγ (1.2)
On the other hand, in a non-Newtonian fluid, theviscosity depends on the shear rate. Besides showingvery high non-Newtonian viscosities, polymers exhibit acomplex viscoelastic flow behavior, that is, their flowexhibits “memory”, as it includes an elastic component inaddition to the purely viscous flow. Rheological propertiesare those that define the flow behavior, such as the viscosityand the melt elasticity, and they determine how easyor difficult is to process these materials, as well as theperformance of the polymer in some applications. Therheology of the polymers and its effect on the processingof these materials are studied in Chapters 22 and 23.
1.1.4 Polymer States
There are several scales at which polymers can be observed.The repeating unit in a polymeric chain lies in the scaleof a few angstroms, while a single polymer molecule orchain has characteristic lengths of a few to some tens ofnanometers (considering the contour length of a chain). Atthe next scale, or mesoscale, clusters of chains can be ob-served. This scale is rather important since it defines thepolymer morphology based on the order or disorder exhib-ited by the chains. Ordered regions are termed crystallineand disordered ones amorphous . In the crystalline regions,the polymer chains are packed in regular arrays termed
INTRODUCTION TO POLYMERS 5
102
103
104
105
10 2 3 4 5 6
13
4
2 1. Fiber2. Rigid plastic3. Flexible plastic4. Elastomer
e
s
Figure 1.1 Schematic stress–strain curves for different types of polymers.
TABLE 1.1 Typical Values of Mechanical Properties for Different Polymer Types
Type of Polymer (use) Modulus (N/m2) Typical Elongations (Strain %) Examples
Elastomers <2 × 106 400–1000 Polybutadiene, polyisoprene, butyl rubberFibers >2 × 109 100–150 Nylon (polyamide), polypropyleneFlexible thermoplastics 0.15−3.5 × 109 20–800 PolyethyleneRigid thermoplastics 0.7−3.5 × 109 0.5–10 Polystyrene, PMMA, phenol-formaldehyde resins
Abbreviation: PMMA, Poly(methyl methacrylate).
crystallites . Crystalline morphology is favored by structuralregularity in the polymer chain and by strong intermolec-ular forces, as well as by some chain flexibility. Usually,in a crystalline polymer, both ordered and disordered re-gions are found; thus, the so-called crystalline polymersare actually semicrystalline. Examples of highly crystallinepolymers are polyethylene and polyamides. On the otherhand, completely amorphous polymers that owe their disor-dered morphology to bulky substituents and rigid chains arecommon, atactic polystyrene and poly methyl methacrylatebeing good examples of this category.
There are two important thermal properties that definethe state of a polymer; these are the glass-transitiontemperature or Tg and the melting temperature, Tm. Belowthe glass-transition temperature, the amorphous regions ofa polymer are in a glassy state showing practically no chainmotions (at least in a practical time scale). Above the Tg, thepolymer behaves as a viscous liquid reflecting motions ofthe polymer chains or chain segments. Also, at the Tg, manyof the physicochemical properties of the polymer change ina relatively abrupt way (Fig. 1.2). The Tg can be definedin more precise thermodynamic terms, but this is furtherdiscussed in Chapter 2.
On the other hand, the Tm is a property exhibited bythe crystalline regions of a polymer and is the temperature
Tg1 Tg2 Tm2
Temperature (°C)
Spe
cific
vol
ume
(l/g)
1. Amorphous
2. Crystalline
1
2
Figure 1.2 Schematic representation of the main thermaltransitions in polymers in a plot of specific volume–temperature.
above which the crystalline regions melt and becomedisordered or amorphous. Since, for a given polymerTm > Tg, above the melting point, the polymer will flow asa viscous liquid. Amorphous polymers exhibit only a Tg,while semicrystalline polymers exhibit both, a Tg and a Tm.
6 INTRODUCTION TO POLYMERS AND POLYMER TYPES
1.1.5 Molecular Weight
Compounds made of small molecules exhibit a unique well-defined molecular weight; on the other hand, polymersexhibit a distribution of molecular weights since notall the polymer chains of a given sample will havethe same molecular weight or chain length. Therefore,in order to characterize a given polymer sample, it isnecessary to either describe the full molecular weightdistribution (MWD) or some average quantities related tothe distribution. Also, the MWD can be plotted in differentways using either length or weight for the abscissa and,for example, number average or weight average for theordinate; the classical paper of Ray [5] shows differentrepresentations of the MWD. Two of the most commonaverages are the number average and weight averagemolecular weights, Mn and Mw, respectively, which aredefined as
Mn =∑
x
f nx Mx (1.3)
Mw =∑
x
f wx Mx (1.4)
where f nx is the number fraction of chains having x
monomer units and Mx is the molecular weight of a chainhaving x monomer units. Also,
Mx = xM0 (1.5)
with M0 being the molecular weight of the monomer unit.f w
x is the weight fraction of chains having x monomerunits. In these definitions, and assuming long chains, thecontribution of any initiator fragment at the end of a chainhas been neglected. In mathematical terms, the number andweight fractions are defined as follows:
f nx = Nx∑
x
Nx
(1.6)
f wx = xNx∑
x
xNx
(1.7)
where Nx is the number of chains having x monomer units.Also note that
f wx = xNx∑
x
xNx
= xf nx∑
x
xf nx
(1.8)
Other related quantities that are frequently used arethe number average chain length (NACL) and the weightaverage chain length (WACL); also represented as rn andrw, respectively, in some texts. The NACL is also simply
termed the degree of polymerization or DPn . They aresimply related to Mn and Mw by the following equations:
NACL = Mn
M0(1.9)
WACL = Mw
M0(1.10)
Instead of giving average based on the weight of therepeating unit, these two quantities are based on the numberof repeating units.
1.1.5.1 Moments of the Molecular Weight DistributionSince the molecular weight is a distributed quantity, theconcepts and properties of statistical distributions canbe applied to the MWD. A statistical definition that isparticularly useful is that of moment of a distribution. Instatistics, the S th moment of the discrete distribution2 f ofa discrete random variable yi is defined as
μS =∞∑i=1
ySi f(yi
), S = 0, 1, 2, . . . (1.11)
A graphical representation of the discrete distributionf (yi ) is shown in Figure 1.3a. Figure 1.3b shows theanalogous MWD represented as the (number) distributionf n
x of the discrete variable Mx (notice the equivalence of theconcept of distribution with those of fraction or frequency).
Equivalently, the S th moment of the MWD can bedefined as
μS =∞∑
X=1
MSx f n
x , S = 0, 1, 2, . . . (1.12)
Now, the average molecular weights of the MWD canbe more simply defined in terms of the moments (Eq. 1.12).
The number average molecular weight is simply
Mn = μ1
μ0(1.13)
since
μ1
μ0=
∞∑X=1
Mxfnx
∞∑X=1
f nx
= Mn
1(1.14)
2Notice that here we use the concept of distribution in a non-rigorousstatistical sense. In rigorous statistical terms “distribution” usually alludesto the cumulative distribution function. Here, as in common language, by“distribution” we mean what in rigorous statistical terms is denoted as“density function” or “probability function”.