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I.W

Handbook of Polymer

Reaction Engineering

Edited by

Th. Meyer, J. Keurentjes

Handbook of Polymer Reaction Engineering. Edited by T. Meyer, J. KeurentjesCopyright 8 2005 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimISBN: 3-527-31014-2

Further Titles of Interest

E. S. Wilks (Ed.)

Industrial Polymers Handbook

Products, Processes, Applications

2000

ISBN 3-527-30260-3

H.-G. Elias (Ed.)

MacromoleculesVols. 14

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ISBN 3-527-31172-6, 3-527-31173-4, 3-527-31174-2,

3-527-31175-0

M. F. Kemmere, Th. Meyer (Eds.)

Supercritical Carbon Dioxidein Polymer Reaction Engineering

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M. Xanthos (Ed.)

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R. C. Advincula, W. J. Brittain, K. C. Caster, J. Ruuhe (Eds.)

Polymer Brushes

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ISBN 3-527-31033-9

H.-G. Elias (Ed.)

An Introduction to Plastics

Second, Completely Revised Edition

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Handbook of Polymer Reaction Engineering

Edited by

Thierry Meyer, Jos Keurentjes

Editors

Dr. Thierry Meyer

Swiss Federal Institute of Technology

Institute of Process Science

EPFL, ISP-GPM

1015 Lausanne

Switzerland

Prof. Jos T. F. Keurentjes

Process Development Group

Eindhoven University of Technology

P.O. Box 513

5600 MB Eindhoven

The Netherlands

9 All books published by Wiley-VCH are

carefully produced. Nevertheless, authors,

editors, and publisher do not warrant the

information contained in these books,

including this book, to be free of errors.

Readers are advised to keep in mind that

statements, data, illustrations, procedural

details or other items may inadvertently be

inaccurate.

Library of Congress Card No.: Applied for

British Library Cataloging-in-Publication

Data: A catalogue record for this book is

available from the British Library

Bibliographic information published by

Die Deutsche Bibliothek

Die Deutsche Bibliothek lists this publica-

tion in the Deutsche Nationalbibliograe;

detailed bibliographic data is available in

the Internet at hhttp://dnb.ddb.dei.

8 2005 WILEY-VCH Verlag GmbH & Co.KGaA, Weinheim

All rights reserved (including those of

translation into other languages). No part of

this book may be reproduced in any form

nor transmitted or translated into machine

language without written permission

from the publishers. Registered names,

trademarks, etc. used in this book, even

when not specically marked as such, are

not to be considered unprotected by law.

Printed in the Federal Republic of Germany

Printed on acid-free paper

Composition Asco Typesetters, Hong Kong

Printing betz-druck gmbh, Darmstadt

Bookbinding Litges & Dopf Buchbinderei

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ISBN-13 978-3-527-31014-2

ISBN-10 3-527-31014-2

Foreword

A principal dierence between science and engineering is intent. Science is used

to bring understanding and order to a specic object of study to build a body of

knowledge with truth and observable laws. Engineering is more applied and prac-

tical, focused on using and exploiting scientic understanding and scientic prin-

ciples to make products to benet mankind. A polymer reaction engineer seeks the

applied and practical as the title implies, but the path to success is most often

through polymer science. This truth is steeped in history there are many exam-

ples of polymeric products commercialized without adequate understanding of the

chemistry and physics of the underlying polymerization. Polymer reaction engi-

neers, faced with detriments in process safety, product quality or product cost, be-

come the driving force behind many polymer science developments. As such, poly-

mer reaction engineering is more a collaboration of polymer science and reaction

engineering. A collaboration where polymer reaction engineers develop a rm un-

derstanding of the many aspects of polymer chemistry and physics to successfully

apply chemical engineering principles to new product developments. Only through

the integration of science and engineering are such products realized.

This handbook is a testimony to this melding of polymer science and chemical

engineering that denes polymer reaction engineering. Thierry Meyer and Jos

Keurentjes have compiled a strong list of contributors with an even balance from

academia and industry. The text oers a comprehensive view of polymer reaction

engineering. The text starts with an overview describing the important integration

of science and engineering in polymer reaction engineering and ends with recent

and potential breakthrough developments in polymer processing. The middle

chapters are divided into three sections. The rst section is devoted to the science

and chemistry of the major types of polymerization. Included are step and chain

growth polymerizations with chapters devoted specically to several dierent chain

growth methods. The central section of the middle chapters is dedicated to poly-

mer reaction engineering tools and methods. The very important topics of safety

and process control are detailed and help frame the conditions through which suc-

cessful scale-ups are achieved. The last section of the middle chapters is focused on

the physics and physical nature of formed polymers including their physical and

mechanical structure. In these chapters, many of the processes that modify poly-

V

mers through man-made and natural change are discussed. The details of polymer

end use are also presented.

This tome represents the rst published handbook on polymer reaction engi-

neering and should be well received in academia and industry. Polymer reaction

engineering became recognized as a separate engineering discipline in the 1970s.

It is well past due that such a handbook be published. The broad scope and depth

of coverage should make it an important reference for years to come.

Michael C. Grady, ScD

Senior Engineering Associate

DuPont

Philadelphia, Pennsylvania

VI Foreword

Contents

Volume 1

Foreword V

Preface XXIX

List of Contributors XXXI

1 Polymer Reaction Engineering, an Integrated Approach 1

Th. Meyer and J. T. F. Keurentjes

1.1 Polymer Materials 1

1.2 A Short History of Polymer Reaction Engineering 4

1.3 The Position of Polymer Reaction Engineering 5

1.4 Toward Integrated Polymer Reaction Engineering 7

1.5 The Disciplines in Polymer Reaction Engineering 9

1.5.1 Polymerization Mechanisms 11

1.5.2 Fundamental and Engineering Sciences 12

1.6 The Future: Product-inspired Polymer Reaction Engineering 14

1.7 Concluding Remarks 15

References 15

2 Polymer Thermodynamics 17

Theodoor W. de Loos

2.1 Introduction 17

2.2 Thermodynamics and Phase Behavior of Polymer Solutions 18

2.2.1 Thermodynamic Principles of Phase Equilibria 18

2.2.2 Fugacity and Activity 18

2.2.3 Equilibrium Conditions 20

2.2.4 Low-pressure VaporLiquid Equilibria 21

2.2.5 FloryHuggins Theory and LiquidLiquid Equilibria 21

2.2.6 High-pressure LiquidLiquid and VaporLiquid Equilibria 25

2.3 Activity Coecient Models 29

2.3.1 FloryHuggins Theory 30

VII

2.3.2 Hansen Solubility Parameters 32

2.3.3 Correlation of Solvent Activities 34

2.3.4 Group Contribution Models 35

2.4 Equation of State Models 39

2.4.1 The SanchezLacombe Lattice Fluid Theory 40

2.4.2 Statistical Associating-uid Theory 44

2.4.2.1 SAFT and PC-SAFT Hard Chain Term 44

2.4.2.2 SAFT Dispersion Term 45

2.4.2.3 The PC-SAFT Dispersion Term 46

2.4.2.4 SAFT and PC-SAFT Applications 47

2.4.2.5 Extension to Copolymers 48

2.5 Conclusions 50

Notation 52

References 54

3 Polycondensation 57

Mario Rui P. F. N. Costa and Rolf Bachmann

3.1 Basic Concepts 57

3.1.1 A Brief History 57

3.1.2 Molecular Weight Growth and Carothers Equation 59

3.1.3 The Principle of Equal Reactivity and the Prediction of the Evolution of

Functional Group Concentrations 62

3.1.4 Eect of Reaction Media on Equilibrium and Rate Parameters 62

3.1.5 Polycondensation Reactions with Substitution Eects 64

3.1.6 Exchange Reactions 66

3.1.7 Ring-forming Reactions 67

3.1.8 Modeling of Polymerization Schemes 68

3.2 Mass Transfer Issues in Polycondensations 69

3.2.1 Removal of Volatile By-products 69

3.2.2 Solid-state Polycondensation 80

3.2.3 Interfacial Polycondensation 82

3.3 Polycondensation Processes in Detail 85

3.3.1 Polyesters 85

3.3.1.1 Structure and Production Processes 85

3.3.1.2 Acid-catalyzed Esterication and Alcoholysis 86

3.3.1.3 Catalysis by Metallic Compounds 87

3.3.1.4 Side Reactions in Aromatic Polyester Production 89

3.3.1.5 Side Reactions in the Formation of Unsaturated Polyesters 90

3.3.1.6 Modeling of Processes of Aromatic Polyester Production 91

3.3.1.7 Modeling of Processes for Unsaturated Polyester Production 92

3.3.2 Polycarbonates 93

3.3.2.1 General Introduction 93

3.3.2.2 Interfacial Polycondensation 94

3.3.2.3 Melt Transesterication 96

3.3.3 Polyamides 98

VIII Contents

3.3.3.1 Introduction 98

3.3.3.2 Kinetic Modeling 98

3.3.3.3 Nonoxidative Thermal Degradation Reactions 100

3.3.3.4 Process Modeling 101

3.3.4 Polymerizations with Formaldehyde: Amino Resins (Urea and

Melamine) and Phenolics 102

3.3.4.1 Formaldehyde Solutions in Water 102

3.3.4.2 Amino Resins 102

3.3.4.3 Phenolic Resins 107

3.3.5 Epoxy Resins 108

3.3.6 Polyurethanes and Polyureas 109

3.4 Modeling of Complex Polycondensation Reactions 113

3.4.1 Overview 113

3.4.2 Description of Reactions in Polycondensations of Several Monomers

with Substitution Eects 113

3.4.3 Equilibrium Polycondensations with Several Monomers 117

3.4.4 Kinetic Modeling of Irreversible Polycondensations 129

3.4.5 Kinetic Modeling of Linear Reversible Polycondensations 133

Notation 136

References 144

4 Free-radical Polymerization: Homogeneous 153

Robin A. Hutchinson

4.1 FRP Properties and Applications 153

4.2 Chain Initiation 154

4.3 Polymerization Mechanisms and Kinetics 156

4.3.1 Homopolymerization 157

4.3.1.1 Basic Mechanisms 157

4.3.1.2 Kinetic Coecients 161

4.3.1.3 Additional Mechanisms 169

4.3.2 Copolymerization 179

4.3.2.1 Basic Mechanisms 179

4.3.2.2 Kinetic Coecients 183

4.3.2.3 Additional Mechanisms 187

4.3.3 Diusion-controlled Reactions 190

4.4 Polymer Reaction Engineering 193

4.4.1 Types of Industrial Reactors 195

4.4.1.1 Batch Processes 195

4.4.1.2 Semi-batch Processes 196

4.4.1.3 Continuous Processes 196

4.4.2 Mathematical Modeling of FRP Kinetics 197

4.4.2.1 Method of Moments 198

4.4.2.2 Modeling of Distributions 201

4.4.3 Reactor Modeling 203

4.4.3.1 Batch Polymerization 204

Contents IX

4.4.3.2 Continuous Polymerization 204

4.4.3.3 Complex Flowsheets 205

4.4.3.4 Computational Fluid Dynamics (CFD) 205

4.4.3.5 Model-based Control 206

4.5 Summary 206

Notation 206

References 209

5 Free-radical Polymerization: Suspension 213

B. W. Brooks

5.1 Key Features of Suspension Polymerization 213

5.1.1 Basic Ideas 213

5.1.2 Essential Process Components 214

5.1.3 Polymerization Kinetics 214

5.1.4 FluidFluid Dispersions and Reactor Type 215

5.1.5 Uses of Products from Suspension Polymerization 216

5.2 Stability and Size Control of Drops 216

5.2.1 Stabilizer Types 217

5.2.2 Drop Breakage Mechanisms 218

5.2.3 Drop Coalescence 222

5.2.4 Drop Size Distributions 223

5.2.5 Drop Mixing 224

5.3 Events at High Monomer Conversion 228

5.3.1 Breakage of Highly Viscous Drops 229

5.3.2 Polymerization Kinetics in Viscous Drops 229

5.3.3 Consequences of Polymer Precipitation Inside Drops 230

5.4 Reaction Engineering for Suspension Polymerization 234

5.4.1 Dispersion Maintenance and Reactor Choice 234

5.4.2 Agitation and Heat Transfer in Suspensions 235

5.4.3 Scaleup Limitations with Suspension Polymerization 237

5.4.4 Reactor Safety with Suspension Processes 238

5.4.5 Component Addition during Polymerization 238

5.5 Inverse Suspension Polymerization 239

5.5.1 Initiator Types 239

5.5.2 Drop Mixing with Redox Initiators 240

5.6 Future Developments 240

5.6.1 Developing Startup Procedures for Batch and Semi-batch Reactors 240

5.6.2 Maintaining Turbulence Uniformity in Batch Reactors 242

5.6.3 Developing Viable Continuous-ow Processes 242

5.6.4 Quantitative Allowance for the Eects of Changes in the Properties of

the Continuous Phase 242

5.6.5 Further Study of the Role of Secondary Suspending Agents 243

5.6.6 Further Characterization of Stabilizers from Inorganic Powders 243

Notation 243

References 244

X Contents

6 Emulsion Polymerization 249

Jose C. de la Cal, Jose R. Leiza, Jose M. Asua, Alessandro Butte`, Guiseppe Storti,

and Massimo Morbidelli

6.1 Introduction 249

6.2 Features of Emulsion Polymerization 250

6.2.1 Description of the Process 250

6.2.2 Radical Compartmentalization 254

6.2.3 Advantages of Emulsion Polymerization 254

6.3 Alternative Polymerization Techniques 256

6.4 Kinetics of Emulsion Polymerization 258

6.4.1 Monomer Partitioning 259

6.4.2 Average Number of Radicals per Particle 260

6.4.3 Number of Polymer Particles 264

6.4.3.1 Heterogeneous Nucleation 264

6.4.3.2 Homogeneous Nucleation 266

6.4.3.3 Simultaneous Heterogeneous and Homogeneous Nucleation 267

6.4.3.4 Coagulative Nucleation 267

6.5 Molecular Weights 267

6.5.1 Linear Polymers 268

6.5.1.1 ZeroOne System (SmithEwart Cases 1 and 2) 268

6.5.1.2 Pseudo Bulk System (SmithEwart Case 3) 270

6.5.2 Nonlinear Polymers: Branching, Crosslinking, and Gel Formation

272

6.6 Particle Morphology 273

6.7 Living Polymerization in Emulsion 275

6.7.1 Chemistry of LRP 275

6.7.1.1 Nitroxide-mediated Polymerization (NMP) 277

6.7.1.2 Atom-transfer Radical Polymerization (ATRP) 277

6.7.1.3 Degenerative Transfer (DT) 278

6.7.1.4 Reversible AdditionFragmentation Transfer (RAFT) Polymerization

279

6.7.2 Polymerization of LRP in Homogeneous Systems 280

6.7.3 Kinetics of LRP in Heterogeneous Systems 282

6.7.4 Application of LRP in Heterogeneous Systems 284

6.7.4.1 Ab-initio Emulsion Polymerization 284

6.7.4.2 Miniemulsion Polymerization 285

6.8 Emulsion Polymerization Reactors 286

6.8.1 Reactor Types and Processes 286

6.8.1.1 Stirred-tank Reactors 286

6.8.1.2 Tubular Reactors 287

6.8.2 Reactor Equipment 288

6.8.2.1 Mixing 289

6.8.2.2 Heat Transfer 290

6.9 Reaction Engineering 290

6.9.1 Mass Balances 291

Contents XI

6.9.2 Heat Balance 292

6.9.3 Polymer Particle Population Balance (Particle Size Distribution)

294

6.9.4 Scaleup 295

6.10 On-line Monitoring in Emulsion Polymerization Reactors 296

6.10.1 On-line Sensor Selection 297

6.10.1.1 Latex Gas Chromatography 298

6.10.1.2 Head-space Gas Chromatography 298

6.10.1.3 Densimetry 298

6.10.1.4 Ultrasound 299

6.10.1.5 Spectroscopic Techniques 299

6.10.1.6 Reaction Calorimetry 302

6.11 Control of Emulsion Polymerization Reactors 305

Notation 312

References 317

7 Ionic Polymerization 323

Klaus-Dieter Hungenberg


7.2 Anionic Polymerization 325

7.2.1 Anionic Polymerization of Hydrocarbon Monomers Living

Polymerization 326

7.2.1.1 Association Behavior/Kinetics 326

7.2.1.2 Molecular Weight Distribution of Living Polymers 331

7.2.1.3 Side Reactions 336

7.2.1.4 Copolymerization 338

7.2.1.5 Tailor-made Polymers by Living Polymerization Optimization 341

7.2.1.6 Industrial Aspects Production of Living Polymers 343

7.2.2 Anionic Polymerization of Vinyl Monomers Containing Heteroatoms

344

7.2.3 Anionic Polymerization of Monomers Containing Hetero Double Bonds

346

7.2.4 Anionic Polymerization via Ring Opening 346

7.3 Cationic Polymerization 351

7.3.1 Cationic Polymerization of Vinyl Monomers 351

7.3.2 Cationic Ring-opening Polymerization 353

7.4 Conclusion 356

Notation 357

References 359

8 Coordination Polymerization 365

Joao B. P. Soares and Leonardo C. Simon

8.1 Polyolen Properties and Applications 365

8.1.1 Introduction 365

8.1.2 Types of Polyolens and Their Properties 366

XII Contents

8.1.3 The Importance of Proper Microstructural Determination and Control

in Polyolens 369

8.2 Catalysts for Olen Polymerization 372

8.2.1 ZieglerNatta, Phillips, and Vanadium Catalysts 378

8.2.2 Metallocene Catalysts 379

8.2.3 Late Transition Metal Catalysts 381

8.3 Polymerization Kinetics and Mechanism with Coordination Catalysts

383

8.3.1 Comparison between Coordination and Free-radical Polymerization

383

8.3.2 Polymerization Kinetics with Single-site Catalysts 383

8.3.2.1 Homopolymerization 383

8.3.2.2 Copolymerization 388

8.3.3 Polymerization Kinetics with Multiple-site Catalysts 392

8.3.4 Long-chain Branch Formation 395

8.4 Single Particle Models Mass- and Heat-transfer Resistances 399

8.5 Macroscopic Reactor Modeling Population Balances and the Method

of Moments 408

8.5.1 Homopolymerization 408

8.5.2 Copolymerization 413

8.6 Types of Industrial Reactors 416

8.6.1 Gas-phase Reactors 420

8.6.2 Slurry Reactors 422

8.6.3 Solution Reactors 423

8.6.4 Multizone Reactors 425

Notation 425

References 428

9 Mathematical Methods 431

P. D. Iedema and N. H. Kolhapure


9.2 Discrete Galerkin hp Finite Element Method 4329.3 Method of Moments 435


9.3.2 Linear Polymerization 435

9.3.3 Nonlinear Polymerization 438

9.4 Comparison of Galerkin-FEM and Method of Moments 440

9.5 Classes Approach 444


9.5.2 Computing the CLD of Poly(vinyl acetate) for a Maximum of One TDB

per Chain 444

9.5.3 Multiradicals in Radical Polymerization 446

9.6 Pseudo-distribution Approach 449


9.6.2 CLD/DBD for Mixed-metallocene Polymerization of Ethylene 451

Contents XIII

9.6.2.1 Formulation of Pseudo-distribution Problem 451

9.6.2.2 Construction of the Full 2D Distribution 456

9.6.3 CLD/Number of Terminal Double Bonds (TDB) Distribution for

Poly(vinyl acetate) More than one TDB per Chain 458

9.6.3.1 General Case 458

9.6.3.2 TDB Pseudo-distribution Approach for a Maximum of one TDB per

Chain 466

9.6.3.3 TDB Pseudo-distribution Approach for More than one TDB per Chain

467

9.6.4 Radical Polymerization of Ethylene to Low-density Polyethylene (LDPE)

469


9.6.5 Radical Copolymerization 473


9.6.5.2 Balance Equations 474

9.7 Probability Generating Functions 480


9.7.2 Probability Generating Functions in a Transformation Method 480

9.7.3 Probability Generating Functions and Cascade Theory 481

9.8 Monte Carlo Simulations 485


9.8.2 Weight-fraction Sampling of Primary Polymers: Batch Reactor,

Transfer to Polymer 486

9.8.3 Example 490

9.8.4 CSTR with Transfer to Polymer 491

9.8.5 Comparison of Galerkin-FEM Classes Model and CSTR with Transfer

to Polymer 492

9.8.6 Batch Reactor, Terminal Double Bond Incorporation 493

9.8.7 CSTR, Terminal Double Bond Incorporation 497

9.8.8 Incorporation of Recombination Termination 498

9.8.9 Incorporation of Random Scission, Linear Chains, Batch Reactor 498

9.8.10 Combined Scission/Branching 501

9.8.11 Scission in a CSTR 501

9.9 Prediction of Branched Architectures by Conditional Monte Carlo

Sampling 502


9.9.2 Branched Architectures from Radical Polymerization in a CSTR 503

9.9.3 Branched Architectures from Polymerization of Olens with Single

and Mixed Branch-forming Metallocene Catalysts in a CSTR 505


9.9.3.2 Single-catalyst System 505

9.9.3.3 Synthesis of Topology 505

9.9.3.4 Mixed-catalyst System 508

9.9.4 Mathematical Methods for Characterization of Branched Architectures

510

9.9.4.1 Graph Theoretical Connectivity Matrices 510

XIV Contents

9.9.4.2 Characterization of Architectures by Radius of Gyration 511

9.9.4.3 Characterization of Architectures by Seniorities and Priorities 512

9.10 Computational Fluid Dynamics for Polymerization Reactors 517


9.10.1.1 Modeling Challenges 517

9.10.2 Development and Optimization of Modern Polymerization Reactors

518

9.10.2.1 Benets of CFD 519

9.10.2.2 Limitations of CFD 519

9.10.3 Integration of CFD with Polymerization Kinetics 520

9.10.3.1 Classication and Complexity of CFD Models 521

9.10.3.2 Treatment of Polymerization Kinetics 522

9.10.3.3 Illustration of Homogeneous Reactor Model Formulation 522

9.10.4 Target Applications 523

9.10.4.1 Illustrative Case Studies 523

9.10.5 Concluding Remarks 528

Acknowledgments 530

References 530

10 Scaleup of Polymerization Processes 533

E. Bruce Nauman

10.1 Historic and Economic Perspective 533

10.2 The Limits of Scale 533

10.3 Scaleup Goals 534

10.4 General Approaches 535

10.5 Scaleup Factors 537

10.6 Stirred-tank Reactors 537

10.7 Design Considerations for Stirred Tanks 541

10.8 Multiphase Stirred Tanks 542

10.9 Stirred Tanks in Series 542

10.10 Tubular Reactors 543

10.11 Static Mixers 545

10.12 Design Considerations for Tubular Reactors 546

10.13 Extruder and Extruder-like Reactors 549

10.14 Casting Systems 549

10.15 Concluding Remarks 550

Notation 550

References 551

Volume 2

11 Safety of Polymerization Processes 553

Francis Stoessel


11.2 Principles of Chemical Reactor Safety Applied to Polymerization 554

11.2.1 Cooling Failure Scenario 554

Contents XV

11.2.2 Criticality Classes Applied to Polymerization Reactors 557

11.2.2.1 Description of the Criticality Classes 558

11.2.3 Heat Balance of Reactors 559

11.2.3.1 Heat Production 559

11.2.3.2 Heat Exchange 560

11.2.3.3 Heat Accumulation 561

11.2.3.4 Convective Heat Transport due to Feed 561

11.2.3.5 Stirrer 561

11.2.3.6 Heat Losses 562

11.2.3.7 Simplied Expression of the Heat Balance 562

11.2.4 Dynamic Control of Reactors 562

11.2.5 Thermal Stability of Polymerization Reaction Masses 563

11.3 Specic Safety Aspects of Polymerization Reactions 564

11.3.1 Kinetic Aspects 564

11.3.2 Thermochemical Aspects 565

11.3.3 Factors Leading to Changing Heat Release Rates 568

11.4 Cooling of Polymerization Reactors 570

11.4.1 Indirect Cooling: Heat Exchange Across the Reactor Wall 570

11.4.2 Hot Cooling: Cooling by Evaporation 574

11.4.3 Importance of the Viscosity 578

11.5 Chemical Engineering for the Safety of Polymerization Processes

579

11.5.1 Batch Processes 579

11.5.2 Semi-batch Processes 580

11.5.2.1 Initiation 581

11.5.2.2 Feed 582

11.5.2.3 Final Stage 583

11.5.2.4 Practical Aspects 583

11.5.3 Continuous Processes 584

11.5.3.1 Concentration Stability 584

11.5.3.2 Particle Number Stability 584

11.5.4 Design Measures for Safety 585

11.5.4.1 Process Design 586

11.5.4.2 Reactor Design 586

11.5.4.3 Control of Feed 587

11.5.4.4 Emergency Cooling 587

11.5.4.5 Inhibition 588

11.5.4.6 Quenching 588

11.5.4.7 Dumping 588

11.5.4.8 Controlled Depressurization 588

11.5.4.9 Pressure Relief 588

11.5.4.10 Time Factor 589

11.6 Conclusion 589

References 590

Notation 591

XVI Contents

12 Measurement and Control of Polymerization Reactors 595

John R. Richards and John P. Congalidis


12.1.1 Denitions 595

12.1.2 Measurement Error 597

12.2 Measurement Techniques 598

12.2.1 Temperature 599

12.2.1.1 Resistance Thermometers 599

12.2.1.2 Thermocouples 600

12.2.1.3 Expansion Thermometers 601

12.2.1.4 Radiation Pyrometers 601

12.2.2 Pressure Measurement 602

12.2.3 Weight 604

12.2.4 Liquid Level 605

12.2.5 Flow 608

12.2.6 Densitometry, Dilatometery, and Gravimetry 617

12.2.7 Viscosity 619

12.2.8 Composition 620

12.2.9 Surface Tension 622

12.2.10 Molecular Weight Distribution (MWD) 622

12.2.11 Particle Size Distribution (PSD) 623

12.3 Sensor Signal Processing 625

12.3.1 Sensors and Transmitters 625

12.3.2 Converters 626

12.3.3 Indicators 626

12.3.4 Filtering Techniques 627

12.4 Regulatory Control Engineering 627

12.4.1 General 627

12.4.2 Process Dynamics 630

12.4.2.1 First-order System 631

12.4.2.2 Second-order System 632

12.4.2.3 High-order and Dead Time Systems 636

12.4.2.4 First-order Plus Dead Time System 636

12.4.2.5 Integrating System 638

12.4.2.6 Integrator plus Dead Time System 639

12.4.3 Controllers 639

12.4.3.1 Proportional Control 640

12.4.3.2 Integral Control 641

12.4.3.3 Derivative Control 641

12.4.3.4 PI, PD, and PID Control 642

12.4.3.5 Digital Controllers 642

12.4.3.6 Controller Tuning 644

12.4.3.7 OnO Controllers 646

12.4.3.8 Self-operated Regulators 647

12.4.4 Valve Position Controllers 650

Contents XVII

12.4.5 Single-loop Controllers 650

12.4.6 Digital Control Systems 650

12.4.7 Actuators 652

12.5 Advanced Control Engineering 656

12.5.1 Feedforward Control 659

12.5.1.1 Steady-state Model Feedforward Control 660

12.5.1.2 Ratio Control 660

12.5.2 Cascade Control 661

12.5.3 FeedforwardFeedback Control 663

12.5.4 State Estimation Techniques 666

12.5.5 Model Predictive Control 668

12.5.6 Batch and Semi-batch Control 669

12.5.6.1 Operation and Variability 669

12.5.6.2 Statistical Process Control 671

12.5.7 Future Trends 671

Notation 672

References 675

13 Polymer Properties through Structure 679

Uday Shankar Agarwal

13.1 Thermal Properties of Polymers 679

13.1.1 Crystalline and Amorphous Polymers 680

13.1.2 Inuence of Polymer Structure on Crystallizability of Polymers 682

13.1.3 The Glass Transition Temperature 683

13.1.4 Inuence of Polymer Structure on Tg of Polymers 68413.1.5 The Crystallization Temperature and the Melting Point 686

13.1.6 Tuning Polymer Crystallization for Properties 686

13.1.7 Morphology of Crystalline Polymers 688

13.1.8 Tailoring Polymer Properties through Modication, Additives, and

Reinforcement 690

13.1.8.1 New Morphologies through Block Copolymers 691

13.1.8.2 Polymeric Nanocomposites 692

13.2 Polymer Conformation and Related Properties 692

13.2.1 The Chain Conformation 692

13.2.2 Solubility of Polymers 694

13.2.3 Dilute Solution Zero-shear Viscosity 695

13.2.3.1 Polymers as Dumbbells 696

13.2.3.2 Polymers as Chains of Beads and Springs 697

13.2.4 Viscosity of Concentrated Solutions and Melts 698

13.2.5 Nonlinear Polymers 699

13.2.6 Rigid Rod-like Polymers 701

13.3 Polymer Rheology 702

13.3.1 The Viscous Response: Shear Thinning 702

13.3.2 Normal Stresses during Shear Flow 703

13.3.3 Extensional Thickening 705

XVIII Contents

13.3.4 The Elastic Response 706

13.3.4.1 Ideal Elastic Response 706

13.3.4.2 Rubberlike Elasticity 706

13.3.5 The Viscoelastic Response 707

13.3.5.1 Linear Viscoelasticity in Dynamic Oscillatory Flow 709

13.3.6 Inuence of Polymer Branching Architecture in Bulk Polymers 711

13.3.7 Polymers as Rheology Modiers 712

13.3.8 Rheological Control with Block Copolymers 714

13.3.9 Polymer-like Structures through Noncovalent Associations 715

13.4 Summary 715

Notation 716

References 718

14 Polymer Mechanical Properties 721

Christopher J. G. Plummer


14.1.1 Long-chain Molecules 721

14.1.2 Simple Statistical Descriptions of Long-chain Molecules 722

14.2 Elasticity 724

14.2.1 Deformation of an Elastic Solid 724

14.2.2 Thermodynamics of Rubber Elasticity 725

14.2.3 Statistical Mechanical Approach to Rubber Elasticity 727

14.3 Viscoelasticity 729

14.3.1 Linear Viscoelasticity 729

14.3.2 TimeTemperature Superposition 734

14.3.3 Molecular Models for Polymer Dynamics 736

14.3.4 Nonlinear Viscoelasticity 740

14.4 Yield and Fracture 741

14.4.1 Yield in Polymers 741

14.4.2 Models for Yield 744

14.4.3 Semicrystalline Polymers 746

14.4.4 Crazing and Fracture 748

14.5 Conclusion 752

References 755

15 Polymer Degradation and Stabilization 757

Tuan Quoc Nguyen


15.2 General Features of Polymer Degradation 759

15.2.1 Degradative Reactions 759


15.2.1.2 Propagation 760

15.2.1.3 Chain Branching 761

15.2.1.4 Termination 762

15.2.2 Some Nonradical Degradation Mechanisms 763

Contents XIX

15.2.3 Physical Factors 763

15.2.3.1 Glass Transition Temperature 764

15.2.3.2 Polymer Morphology 766

15.3 Degradation Detection Methods 767

15.3.1 Mechanical Tests 768

15.3.2 Gel Permeation Chromatography 771

15.3.3 Fourier Transform Infrared Spectroscopy 773

15.3.4 Magnetic Resonance Spectroscopy 775

15.3.4.1 Nuclear Magnetic Resonance (NMR) 775

15.3.4.2 Electron Spin Resonance (ESR) 776

15.3.5 Oxygen Uptake 776

15.3.6 Chemiluminescence 778

15.4 Thermal Degradation 778

15.4.1 Thermal Stability 779

15.4.2 Polymer Structure and Thermal Stability 779

15.4.3 Computer Simulation 780

15.4.4 Thermal Oxidative Degradation of Polypropylene 782


15.4.4.2 Propagation 784

15.4.4.3 Chain Branching 785

15.4.4.4 Termination 786

15.4.4.5 Secondary Reactions 786

15.4.4.6 Formation of Volatile Compounds 788

15.4.5 Homogeneous versus Heterogeneous Kinetics 789

15.4.6 Applications of Thermal Degradation 790

15.4.6.1 Analytical Pyrolysis 790

15.4.6.2 Introduction of New Chemical Functionalities 791

15.4.6.3 Chemical Modication of Polymer Structure 791

15.4.6.4 Metal Injection Molding (MIM) 792

15.4.6.5 Recycling 792

15.5 Photodegradation 793

15.5.1 Absorption of UV Radiation by Polymers 793

15.5.2 The Solar Spectrum 796

15.5.3 Photo-oxidation Prole 796

15.5.4 Inuence of Wavelength: the Activation and Action Spectrum 799

15.5.5 Photodegradation Mechanisms 802

15.5.5.1 Photoinitiation 802

15.5.5.2 The Norrish Photoprocesses 803

15.5.5.3 Photo-Fries Rearrangement 803

15.6 Radiolytic Degradation 805

15.6.1 Interaction of High-energy Radiation with Matter 805

15.6.2 Radiation Chemistry 807

15.6.3 Radiolysis Stabilization 810

15.6.4 Applications 811

15.6.4.1 Radiation Sterilization 812

XX Contents

15.6.4.2 Controlled Degradation and Crosslinking 812

15.7 Mechanochemical Degradation 813

15.7.1 Initiation by Mechanical Stresses 813

15.7.1.1 Eect of Tensile Stress on Chemical Reactivity 813

15.7.1.2 Breaking Strength of a Covalent Bond 814

15.7.1.3 Rate of Stress-activated Chain Scission 815

15.7.2 Extrusion Degradation 816

15.7.3 Applications 817

15.8 Control and Prevention of Aging of Plastic Materials 818

15.8.1 Antioxidants 818

15.8.1.1 Radical Antioxidants 818

15.8.1.2 Hindered Amine Stabilizers (HAS) 819

15.8.1.3 Peroxide Decomposers 821

15.8.2 Photostabilizers 822

15.8.3 PVC Heat Stabilizers 823

15.8.4 Other Classes of Stabilizers 824

15.8.4.1 Metal Deactivators 824

15.8.4.2 Antiozonants 824

15.9 Lifetime Prediction 824

15.10 Conclusions 826

Notation 827

References 830

16 Thermosets 833

Rolf A. T. M. van Benthem, Lars J. Evers, Jo Mattheij, Ad Hoand, Leendert J.

Molhoek, Ad J. de Koning, Johan F. G. A. Jansen, and Martin van Duin


16.1.1 Thermoset Materials 833

16.1.2 Networks 834

16.1.3 Advantages 835

16.1.4 Curing Resins 835

16.1.5 Functionality 835

16.1.6 Formulation 836

16.1.7 Production 837

16.1.8 General Areas of Application 837

16.2 Phenolic Resins 838


16.2.2 Chemistry 838

16.2.2.1 Resols 840

16.2.2.2 Novolacs 840

16.2.2.3 Epoxy-novolacs 841

16.2.2.4 Discoloration 841


16.2.4 Properties and Applications 842

16.3 Amino Resins 843

Contents XXI



16.3.2.1 Polymerization Chemistry 845



16.4 Epoxy Resins 849



16.4.2.1 Cure 851


16.4.3.1 Standard Liquid 853

16.4.3.2 Tay Process 854

16.4.3.3 Advancement Process 854


16.5 Alkyd Resins 855



16.5.2.1 The Alkyd Constant 858

16.5.2.2 Autoxidative Drying 858



16.5.4.1 Short Oil Alkyds 861

16.5.4.2 Long Oil Alkyds 861

16.5.4.3 Medium Oil Alkyds 861

16.5.5 Alkyd Emulsions 861

16.5.5.1 The Inversion Process 862

16.6 Saturated Polyester Resins 862




16.6.3.1 Monitoring the Reaction 865


16.6.5 Powder Coatings 866

16.6.5.1 Application 867

16.6.5.2 Crosslinking 868

16.6.5.3 Advantages 869

16.7 Unsaturated Polyester Resins and Composites 869



16.7.2.1 Crosslinking 871

16.7.2.2 Styrene Emission 871

16.7.2.3 Vinyl Ester Resins 873


16.7.4 Reinforcement 875

16.7.5 Fillers 878

XXII Contents

16.7.6 Processing 879

16.7.6.1 Hand Lay-up and Spray-up 882

16.7.6.2 Continuous Lamination 882

16.7.6.3 Filament Winding 882

16.7.6.4 Centrifugal Casting 882

16.7.6.5 Pultrusion 883

16.7.6.6 Cold-press Molding 883

16.7.6.7 Resin Infusion 883

16.7.6.8 Resin-transfer Molding 883

16.7.6.9 Hot-press Molding 883

16.7.6.10 Casting, Encapsulation, and Coating (Non-reinforced Applications)

886

16.7.7 Design Considerations: Mechanical Properties of Composites 886

16.8 Acrylate Resins and UV Curing 889




16.8.3.1 Epoxy Acrylates 891

16.8.3.2 Polyester Acrylates 891

16.8.3.3 Urethane Acrylates 892

16.8.3.4 Inside-out 893

16.8.3.5 Outside-in 894

16.8.3.6 Comparing Inside-out with Outside-in 894

16.8.3.7 Stabilization 894

16.8.3.8 Dilution 895

16.8.3.9 Safety 895

16.8.4 Properties 895

16.8.5 Introduction to UV Curing 896

16.8.5.1 General Introduction to UV-initiated Radical Polymerization 896

16.8.5.2 Photoinitiators for Radical Polymerization 897

16.8.5.3 Resin 897

16.8.5.4 Reactive Diluent 898

16.8.5.5 Curing Process 899

16.8.5.6 Cationic Curing 900

16.8.5.7 Base-mediated Curing 901

16.9 Rubber 901


16.9.1.1 Types of Rubber 902

16.9.2 Polymerization 903

16.9.3 Crosslinking 904

16.9.3.1 Sulfur Vulcanization 904

16.9.3.2 Peroxide Curing 905

16.9.3.3 Processing 906


16.9.4.1 Advantages and Disadvantages 907

Contents XXIII

16.9.4.2 Thermoplastic Vulcanizates 907

Notation 908

References 909

17 Fibers 911

J. A. Juijn


17.1.1 A Fiber World 911

17.1.2 Scope of this Chapter 912

17.2 Fiber Terminology 912

17.2.1 Denitions: Fibers, Filaments, Spinning 912

17.2.2 Synthetic Yarns 914

17.2.3 Titer: Tex and Denier 914

17.2.4 Tenacity and Modulus: g denierC1, N texC1, or GPa 915

17.2.5 Yarn Appearance 916

17.2.6 Textile, Carpet, and Industrial Yarns 917

17.2.7 Physical Structure 918

17.3 Fiber Polymers: Choice of Spinning Process 920

17.3.1 Polymer Requirements 920

17.3.2 Selection of Spinning Process 920

17.3.3 Spinnability 922

17.4 Melt Spinning 923

17.4.1 Extrusion 923

17.4.2 Polymer Lines and Spin-box 924

17.4.3 Spinning Pumps 925

17.4.4 Spinning Assembly 926

17.4.4.1 Filtration 926

17.4.4.2 Spinning Plate 926

17.4.5 Quenching 928

17.4.6 Finish 929

17.4.7 Spinning Speed 931

17.4.8 Winding 931

17.4.9 Drawing 931

17.4.10 Relaxation and Stabilization 934

17.4.11 Process Integration 934

17.4.12 Rheology 934

17.4.12.1 Shear Viscosity 934

17.4.12.2 Elasticity 936

17.4.12.3 Elongational Viscosity 936

17.4.13 Process Calculations 936

17.4.13.1 Mass Flow 937

17.4.13.2 Volume Flow 937

17.4.13.3 Extrusion Speed and Elongation in the Spin-line 937

17.4.13.4 Pressure Drop over the Spinning Holes 938

XXIV Contents

17.4.14 Polyester (Poly(ethylene terephthalate), PET) 938

17.4.14.1 PET Polymer 938

17.4.14.2 Spinning of PET 939

17.4.14.3 PET Staple Fiber 939

17.4.14.4 PET Textile Filament Yarns 940

17.4.14.5 PET Industrial Yarns 940

17.4.15 Polyamide (PA6 and PA66) 941

17.4.15.1 PA Polymer 941

17.4.15.2 PA Spinning 941

17.4.15.3 PA Staple Fiber 942

17.4.15.4 PA Textile Filament Yarns 942

17.4.15.5 PA Industrial Yarns 942

17.4.16 Polypropylene (PP) 943

17.4.16.1 PP Polymer 943

17.4.16.2 PP Spinning 943

17.4.16.3 PP Staple Fiber 943

17.4.16.4 PP Split Fiber 943

17.4.16.5 PP Filament Yarns 944

17.5 Solution Spinning 944

17.5.1 Preparation of Spinning Dope 944

17.5.2 Dry Spinning 944

17.5.2.1 Cellulose Acetate 945

17.5.2.2 Acrylics 946

17.5.2.3 Poly(vinyl alcohol) 946

17.5.3 Wet Spinning 946

17.5.3.1 Viscose Rayon 948

17.5.3.2 Acrylics 951

17.5.3.3 Poly(vinyl alcohol) 952

17.6 Comparison of Melt and Solution Spinning 953

17.7 High-modulus, High-strength Fibers 956

17.7.1 Air-gap Spinning 956

17.7.1.1 Aramids 956

17.7.1.2 Other Liquid-crystalline Polymers 960

17.7.2 Gel Spinning 961

17.7.2.1 Theory 961

17.7.2.2 Gel Spinning of Polyethylene 962

17.7.2.3 Other Gel-spun or Superdrawn Fibers 964

17.7.3 Carbon Fiber 965

17.7.3.1 Carbon Fiber from PAN 965

17.7.3.2 Carbon Fiber from Pitch 966

17.7.3.3 Applications of Carbon Fibers 966

17.7.4 Other Advanced Fibers 966

Notation 967

Acknowledgments 969

References 969

Contents XXV

18 Removal of Monomers and VOCs from Polymers 971

Mara J. Barandiaran and Jose M. Asua


18.2 Polymer Melts and Solutions 972

18.2.1 Devolatilization 973

18.2.1.1 Fundamentals 973

18.2.1.2 Implementation of Devolatilization 975

18.2.1.3 Equipment 975

18.3 Polyolens 979

18.4 Waterborne Dispersions 979

18.4.1 Post-polymerization 980

18.4.1.1 Modeling Post-polymerization 981

18.4.2 Devolatilization 981

18.4.2.1 Modeling 982

18.4.2.2 Rate-limiting Steps 985

18.4.2.3 Devolatilization under Equilibrium Conditions 986

18.4.2.4 Equipment 986

18.4.3 Combined Processes 988

18.4.4 Alternative Processes 989

18.5 Summary 989

Notation 990

References 991

19 Nano- and Microstructuring of Polymers 995

Christiane de Witz, Carlos Sanchez, Cees Bastiaansen, and Dirk J. Broer


19.1.1 Patterning Techniques 996

19.1.2 Photoembossing 998

19.2 Materials and their Photoresponsive Behavior 999

19.3 Single-exposure Photoembossing 1001

19.4 Dual-exposure Photoembossing 1007

19.5 Complex Surface Structures from Interfering UV Laser Beams 1007

19.6 Surface Structure Development under Fluids 1010

19.7 Conclusion 1012

Acknowledgments 1012

Notation 1013

References 1013

20 Chemical Analysis for Polymer Engineers 1015

Peter Schoenmakers and Petra Aarnoutse


20.2 Process Analysis 1017

20.2.1 Near-infrared Spectroscopy 1017

20.2.2 In-situ Raman Spectroscopy 1018

20.2.3 At-line Conversion Measurements 1020

XXVI Contents

20.3 Polymer Analysis 1022

20.3.1 Basic Laboratory Measurements 1022

20.3.1.1 Conversion 1022

20.3.2 Detailed Molecular Analysis 1023

20.3.2.1 FTIR Spectroscopy 1023

20.3.2.2 NMR Spectroscopy 1024

20.3.2.3 Mass Spectrometry 1025

20.3.3 Polymer Distributions 1030

20.3.3.1 Molecular Weight Distributions 1030

20.3.3.2 Functionality-type Distributions 1034

20.3.3.3 Chemical Composition Distributions (CCDs) 1037

20.3.3.4 Degree of Branching Distributions 1040

20.3.3.5 Complex Polymers (Multiple Distributions) 1041

Notation 1044

References 1045

21 Recent Developments in Polymer Processes 1047

Maartje Kemmere


21.2 Polymer Processes in Supercritical Carbon Dioxide 1048

21.2.1 Interactions of Carbon Dioxide with Polymers and Monomers 1050

21.2.1.1 Solubility in Carbon Dioxide 1051

21.2.1.2 Sorption and Swelling of Polymers 1052

21.2.1.3 Phase Behavior of MonomerPolymerCarbon Dioxide Systems 1054

21.2.2 Polymerization Processes in Supercritical Carbon Dioxide 1055

21.2.3 Polymer Processing in Supercritical Carbon Dioxide 1058

21.2.3.1 Extraction 1060

21.2.3.2 Impregnation and Dyeing 1061

21.3 Ultrasound-induced Radical Polymerization 1062

21.3.1 Ultrasound and Cavitation in Liquids 1063

21.3.2 Radical Formation by Cavitation 1065

21.3.3 Cavitation-induced Polymerization 1067

21.3.3.1 Bulk Polymerization 1067

21.3.3.2 Precipitation Polymerization 1069

21.3.3.3 Emulsion Polymerization 1070

21.3.4 Cavitation-induced Polymer Scission 1072

21.3.5 Synthesis of Block Copolymers 1073

21.4 Concluding Remarks and Outlook for the Future 1074

Acknowledgments 1076

Notation 1076

References 1077

Index 1083

Contents XXVII

Preface

Freshly started as chairman and secretary of the Working Party on Polymer Reac-

tion Engineering it never crossed our mind to edit a book on this subject. This

changed when Wiley-VCH asked if the working party would be able to provide a

translation of the Handbuch der Technischen Polymerchemie, written in 1993 by

Adolf Echte. We decided to do so, but not exactly. Very rapidly we were convinced

that we needed a completely new book, covering the eld of polymer reaction engi-

neering in a modern, broad and multidisciplinary approach. Many of the working

party members directly agreed to participate, others needed somewhat stronger

persuasion techniques, and for some chapters we hired authors from other in-

stitutions. In June 2003 we had completed the list of contributors, coming from

Europe, Canada and the USA. Now, roughly one year later, the new handbook is

there.

The quality an edited book like this very much depends on the quality of the in-

dividual contributions. It has been a great pleasure for us to see that all authors

have taken their writing jobs very seriously. With these contributions, we are sure

that this book represents the state of the art in polymer reaction engineering. It

is intended to attract equally readers that are new in the eld as well as readers

that may be considered expert in some of the topics but want to broaden their

knowledge. We are convinced that the multidisciplinary and synergetic approach

presented in this book may act as an eye-opener for research and development ac-

tivities going on in strongly related areas. We hope the reader will take advantage

of this approach, where the references given in the various chapters may be a start-

ing point for further reading.

Reading books, you often read the preface as well. We have seen numerous ex-

amples from which the frustration is quite obvious. Of course things may not al-

ways work out the way you plan, that has also been the case for this book. Maybe

we were just lucky, but we have greatly enjoyed doing this. Editing this book has

also been a starting point for the editors to become friends, including Swiss cheese

fondue and Dutch Friese nagelkaastaart in a friendly home setting. From that

perspective also Francine and Maartje have had their part both of the workload

but also of the fun of all this.

Finally, we would like to thank Karin Sora and Renate Doetzer from Wiley-VCH

XXIX

for their help with the editing process. They really know to nd the balance be-

tween waiting and pushing in order not to diverge too far from the schedule.

Lausanne & Eindhoven, fall 2004

Thierry Meyer & Jos Keurentjes

XXX Preface

List of Contributors

P. Aarnoutse

Polymer-Analysis Group

Department of Chemical Engineering

(ITS)

Faculty of Science, University of

Amsterdam

Nieuwe Achtergracht 166

1018 WV Amsterdam

The Netherlands

Dr. U. S. Agarwal

Polymer Technology Group


and Chemistry


P.O. Box 513

5600 MB Eindhoven

The Netherlands

Prof. J. M. Asua

The University of the Basque Country

Institute for Polymer Materials

(POLYMAT)

Paseo Manuel Lardizabal 3

20018 Donostia-San Sebastian

Spain

Dr. R. Bachmann

Bayer AG

ZT-TE-SVT

51368 Leverkusen

Germany

Prof. M. J. Barandiaran



(POLYMAT)

Manuel Lardizabal, 3


Spain

Dr. C. W. M. Bastiaansen


Den Dolech 2

5600 MB Eindhoven

The Netherlands

Prof. D. J. Broer

Philips Research Laboratories

Prof. Holstlaan 4

5656 AA Eindhoven

The Netherlands

and


Den Dolech 2

5600 MB Eindhoven

The Netherlands

and

Dutch Polymer Institute (DPI)

P.O. Box 902

5600 AX Eindhoven

The Netherlands

XXXI

Polymer Technology


and Chemistry


P.O. Box 513

5600 MB Eindhoven

The Netherlands

Prof. B. W. Brooks

Loughborough University

Department of Chemical

Engineering

Loughborough

Leicestershire, LE11 3TU

United Kingdom

Dr. A. Butte`

Swiss Federal Institute of

Technology

Zurich, ETHZ

Institut fur Chemie- und

Bioingenieurwissenschaten

Gruppe Morbidelli

ETH Hoenggerberg/HCI F135

8093 Zurich

Switzerland

Dr. J. P. Congalidis

E.I. du Pont de Nemours and

Company

DuPont Central Research and

Development

Experimental Station

Wilmington, DE 19880

USA

Dr. M. R. P. F. N. Costa

Faculty of Engineering

University of Porto

Rua Roberto Frias, s/n

4200-465 Porto

Portugal

Prof. J. C. de la Cal



(POLYMAT)

Paseo Manuel Lardizabal, 3


Spain

Dr. A. J. de Koning

DSM Research

Oude Postbaan 1

6167 RG Geleen

The Netherlands

Dr. T. W. de Loos

Delft University of Technology

Faculty of Applied Sciences

Department Chemical Technology

Julianalaan 136

2628 BL Delft

The Netherlands

C. de Witz

Philips Research Laboratories

Prof. Holstlaan 4

5656 AA Eindhoven

The Netherlands

Dr. L. J. Evers

DSM Melamine

Oude Postbaan 1

6167 RG Geleen

The Netherlands

Dr. A. Hoand

DSM Coating Resins

Ceintuurbaan 5

8022 AW Zwolle

The Netherlands

Dr. K.-D. Hungenberg

BASF AG

Polymer Technology, B1

67056 Ludwigshafen

Germany

XXXII List of Contributors

Prof. R. A. Hutchinson


Queens University

Dupuis Hall, 19 Division St.

Kingston, Ontario K7M 2G9

Canada

Dr. P. D. Iedema


University of Amsterdam


1018 WV Amsterdam

The Netherlands

Dr. J. F. G. A. Jansen

DSM Research

Oude Postbaan 1

6167 RG Geleen

The Netherlands

Dr. J. A. Juijn

Research Institute

Department QRI

P.O. Box 9600

6800 TC Arnheim

The Netherlands

Dr. M. F. Kemmere



and Chemistry


P.O. Box 513

5600 MB Eindhoven

The Netherlands

Prof. J. T. F. Keurentjes



P.O. Box 513

5600 MB Eindhoven

The Netherlands

N. H. Kolhapure

DuPont Engineering Research and

Technology

1007 N. Market St.

Wilmington, DE 19898-0001

USA

Prof. J. R. Leiza



(POLYMAT)

Paseo Manuel Lardizabal 3


Spain

J. Mattheij

DSM Melamine

Oude Postbaan 1

6167 RG Geleen

The Netherlands

Dr. T. Meyer


Institute of Process Science

EPFL, ISP-GPM

1015 Lausanne

Switzerland

L. J. Molhoek

DSM Coating Resins

Ceintuurbaan 5

8022 AW Zwolle

The Netherlands

Prof. M. Morbidelli


Zurich, ETHZ


Bioingenieurwissenschaften

Gruppe Morbidelli


8093 Zurich

Switzerland

List of Contributors XXXIII

Prof. E. B. Nauman

The Isermann Department of Chemical

and Biological Engineering

Rensselaer Polytechnic Institute

Troy, NY 12180

USA

Dr. Q. T. Nguyen

Laboratory of Polymers (LP)

Ecole Polytechnique Federale

de Lausanne

1015 Lausanne

Switzerland

J. C. Plummer

Laboratory of Composite and Polymer

Technology (LTC)

Ecole Polytechnique Federale

de Lausanne

1015 Lausanne

Switzerland

Dr. J. R. Richards

E. I. du pont de Nemours and Company

DuPont Engineering and Research

Technology

Experimental Station

Wilmington, DE 19880

USA

Dr. C. Sanchez


Den Dolech 2

5600 MB Eindhoven

The Netherlands

and

Dutch Polymer Institute (DPI)

P.O. Box 902

5600 AX Eindhoven

The Netherlands

Prof. P. J. Schoenmakers

Polymer-Analysis Group


(ITS)

Faculty of Science, University of

Amsterdam


1018 WV Amsterdam

The Netherlands

Prof. L. C. Simon


University of Waterloo

200 University Avenue West

Waterloo, Ontario N2L 3G1

Canada

Prof. J. B. P. Soares


University of Waterloo

200 University Avenue West

Waterloo, Ontario N2L 3G1

Canada

Prof. F. Stoessel

Swiss Institute for the Promotion of

Safety and Security

Chemical Process Safety Consulting

Klybeckstrasse 141

WKL-32.322

4002 Basel

Switzerland

Prof. G. Storti


Zurich, ETHZ


Bioingenieurwissenschaften

Gruppe Morbidelli


8093 Zurich

Switzerland

XXXIV List of Contributors

Prof. R. A. T .M. van Benthem

Coating Technology


and Chemistry


P.O. Box 513

5600 MB Eindhoven

The Netherlands

Dr. M. van Duin

DSM Research

Oude Postbaan 1

6167 RG Geleen

The Netherlands

List of Contributors XXXV

1Polymer Reaction Engineering, an Integrated

Approach

Th. Meyer and J. T. F. Keurentjes

1.1

Polymer Materials

Synthetic polymers can be denoted as the materials of the 20th century. Since

World War II the production volume of polymers has increased by a factor of 50

to a current value of more than 120 million tonnes annually (Figure 1.1). The con-

sumption per capita has also increased over the years to a worldwide average of ap-

proximately 20 kg per annum in the year 2000. In terms of volumetric output, the

production of polymers exceeds that of iron and steel. The enormous growth of

synthetic polymers is due tot the fact that they are lightweight materials, act as in-

sulators for electricity and heat, cover a wide range of properties from soft packag-

ing materials to bers stronger than steel, and allow for relatively easy processing.

Handbook of Polymer Reaction Engineering. Edited by T. Meyer, J. KeurentjesCopyright 8 2005 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimISBN: 3-527-31014-2

0

5

10

15

20

25

1940 1950 1960 1970 1980 1990 2000Year

0

20

40

60

80

100

120Annual Production 106 to/an

World Population , 109 people

Consumption, kg/hab

2010

Fig. 1.1. Polymer production and the evolution of the population since 1940 [1].

1

Moreover, parts with complex shapes can be made at low cost and at high speed by

shaping polymers or monomers in the liquid state.

The polymer market can be divided into thermoplastics and thermosets. The ma-

jor thermoplastics include high-density polyethylene (HDPE), low-density polyeth-

ylene (LDPE), polyethylene terephthalate (PET), polypropylene (PP), polystyrene

(PS and EPS), poly(vinyl chloride) (PVC), polyamide (PA), poly(methyl methacry-

late) (PMMA) and styrene copolymers (ABS, SAN). The most important applica-

tions of thermoplastics are summarized in Table 1.1. The total Western European

demand for thermoplastics was 37.4 million tonnes in 2002, a growth of about 9%

as compared to 2001 [1]. Thermoplastics are used not only in the manufacture of

many typical plastics applications such as packaging and automotive parts, but also

in non-plastic applications such as textile bers and coatings. These non-plastic ap-

plications account for about 14% of all thermoplastics consumed.

The major thermosets include epoxy resins, phenolics, and polyurethanes (PU),

for which the major applications are summarized in Table 1.2. It has to be noted,

Tab. 1.1. Applications and 2002 Western European markets for the major thermoplastics [1].

Thermoplastic Market

[103 tonnes]

Applications

LDPE 7935 pallet and agricultural lm, bags, toys, coatings,

containers, pipes

PP 7803 lm, battery cases, microwave-proof containers, crates,

automotive parts, electrical components

PVC 5792 window frames, pipes, ooring, wallpaper, bottles, cling

lm, toys, guttering, cable insulation, credit cards,

medical products

HDPE 5269 containers, toys, housewares, industrial wrappings and

lms, pipes

PET 3234 bottles, textile bers, lm food packaging

PS/EPS 3279 electrical appliances, thermal insulation, tape cassettes,

cups and plates, toys

PA 1399 lm for food packaging (oil, cheese, boil-in-bag), high-

temperature engineering applications, textile bers

ABS/SAN 788 general appliance moldings

PMMA 317 transparent all-weather sheet, electrical insulators,

bathroom units, automotive parts

Tab. 1.2. Applications and 2002 Western European markets for the major thermosets [1].

Thermoset Market [103 tonnes] Applications

PU 3089 coatings, nishes, cushions, mattresses, vehicle seats

Phenolics 912 general appliance moldings, adhesives, appliances,

automotive parts, electrical components

Epoxy resins 420 adhesives, automotive components, E&E components,

sports equipment, boats

2 1 Polymer Reaction Engineering, an Integrated Approach

however, that about one-third of the market for thermosets is for relatively small-

scale specialty products. The total Western European market for thermosets was

10.4 million tonnes in 2002, about 1% below the 2001 value.

The major application areas of polymers can be dened as follows (Figure 1.2).

Automotive industry Motorists want high-performing cars combined with reliabil-

ity, safety, comfort, competitive pricing, fuel eciency, and, increasingly, reassur-

ance about the impact on the environment. Lightweight polymeric materials are

increasingly used in this sector (Daimler Benzs Smart is a nice example), also con-

tributing to a 10% reduction in passenger fuel consumption across Europe.

Building and construction Polymeric materials are used in the building and con-

struction sector, for example for insulation, piping, and window frames. In 2002

this sector accounted for 17.6% of the total polymer consumption.

Electrical and electronic industry Many applications in this eld arise from newly

designed polymeric materials, for example for polymeric solar cells and holo-

graphic lms. It is interesting to note that, while the number of applications in

this eld is increasing, the weight of the polymers used per unit is decreasing.

Packaging The packaging sector remains the largest consumer of synthetic poly-

mers, approximately 38% of the total market. This is mainly due to the fact that

these materials are lightweight, exible, and easy to process, and are therefore

increasingly being substituted for other materials. Although polymer packaging

ranks rst in terms of units sold, it is only third if judged on weight.

Agriculture As agricultural applications account for about 2.5% of the total of syn-

thetic polymers consumed in Europe, they play only a marginal role. Irrigation and

Packaging38.1%

Building and construction

17.6%

Electrical and electronics

7.3%

Large industry5.2%

Automotive7.0%

Agriculture2.5%

Domestic22.3%

Fig. 1.2. Plastic consumption in 2002 by industry sectors in Western Europe [1].

1.1 Polymer Materials 3

drainage systems provide eective solutions to crop growing, and polymeric lms

and greenhouses can increase horticultural production substantially. The use of so-

called super absorbers for increased irrigation eciency in arid areas can be con-

sidered an important emerging market.

1.2

A Short History of Polymer Reaction Engineering

In Table 1.3 a comprehensive overview of the major developments in the polymer

industry is given. In the 19th century, polymers produced by Nature, such as cellu-

lose, Hevea brasiliensis latex (natural rubber), and starch, were processed to manu-facture useful products. This practice was often based on experimental discoveries.

As an example, in 1839 Goodyear discovered by mistake the sulfur vulcanization of

natural rubber, making it possible for Ford to develop the automotive market. In

those times no polymers were produced synthetically.

Early in the 20th century (1920), the rst empirical description of macromole-

cules was developed by Staudinger [2]. At the same time, new methods were devel-

oped to determine the specic characteristics of these materials. In the 1930s many

research groups (for examples see refs. 37) developed models for the chain length

distribution in batch reactors resulting from dierent polymer chemistries, a meth-

odology that was further developed in the 1940s leading to more complex and com-

prehensive models, some of which are still being used today.

Tab. 1.3. The history of polymers in brief.

19th century natural polymer and derivatives (vulcanized rubber, celluloid)

1920 concept of macromolecules postulated by Staudinger

19301940 rst systematic synthesis of polymers

synthesis of polyamides (nylon) by Carothers at DuPont

discovery of polyethylene at ICI (Fawcett and Gibson)

19401950 synthetic rubbers and synthetic bers

19501960 stereospecic polymerizations by Ziegler and Natta, the birth of

polypropylene

discovery of polymer single crystals (Keller, Fischer, Till)

development of polycarbonate

19601970 discovery of PPO at GE by Hay and commercialization of PPO/PS

blends (Noryl2)19701980 liquid-crystalline polymers

19801990 superstrong bers (Aramid2, polyethylene)functional polymers (conductive, light-emitting)

19902000 metallocene-based catalysts; novel polyolens hybrid systems

(polymer/ceramic, polymer/metals)

2000 Nature-inspired catalysts

synthesis of polymers by bacteria and plants


Around 1940, partly inspired by World War II, a more systematic search for new

synthetic polymer materials as a replacement for scarce natural materials led to the

development of nylon (DuPont) and polyethylene (ICI) [8, 9]. This was followed by

the development of synthetic rubbers and synthetic bers. In the same period,

Denbigh [10] was one of the rst to introduce chemical reaction engineering con-

cepts into polymer science by considering polymerization reactions at both the

chemical and at the process levels. Processes were classied as homocontinuous

and heterocontinuous, depending on the mixing level. This pioneering approach

also acted as a catalyst for the further development of polymer reaction engineer-

ing (PRE).

The development of catalysts based on transition metals by Ziegler and Natta

[11] allowed the development of stereospecic propylene polymerization processes

and ethylene polymerization in the 1950s. Several process schemes were developed

at that time, of which some are still in use. The major problem in process develop-

ment has been to deal with the heat of polymerization, an issue that was solved, for

example, by using an inert solvent as a heat sink or by ashing of monomer fol-

lowed by condensation outside the reactor. In the same period, polycarbonate and

(somewhat later) poly(propylene oxide) (PPO) were developed. The main character-

istic of the polymers developed so far was that they were bulk materials, to be pro-

duced in extremely large quantities.

In the 1970s, a paradigm shift occurred when polymers with more specic prop-

erties started to be produced. This included various liquid crystalline polymers

leading, for example, to the production of superstrong bers such as Aramid2/Kevlar2 [12]. The development of functional polymers for the conduction of lightand electricity and optical switches also started then [13]. In the near future this

will probably lead to highly eective and exible polymer solar cells [14].

In the 1990s, metallocene catalysts were developed for polyolen production that

surpassed the ZieglerNatta catalysts in terms of selectivity and reactivity [15, 16].

Additionally, various hybrid materials were combining properties of both the poly-

mer (lightweight, exible) and a solid material, which could be metal (conductive)

or ceramic (insulating), leading to materials with specic properties applicable, for

example, as protective coatings [17].

Current developments include the mimicking of nature (enzymes) for the syn-

thesis of quite complex polymers like natural silk. Also, bacteria and plants are be-

ing modied to produce polymers of interest [18]. However, this can be expected

to require polymer reaction engineering developments that are as yet dicult to

foresee.

1.3

The Position of Polymer Reaction Engineering

Traditional chemical reaction engineering has its basis in the application of scien-

tic principles (from disciplines such as chemistry, physics, biology, and mathe-

matics) and engineering knowledge (transfer of heat, mass, and momentum) to

1.3 The Position of Polymer Reaction Engineering 5

the solution of problems of practical, industrial, and societal importance. Since the

1970s, a changing focus in chemical reaction engineering can be observed, which

is summarized in Figure 1.3.

To deal with more stringent requirements in terms of energy consumption re-

quires a shift from heat loss minimization toward novel intensied process con-

cepts that intrinsically require less energy. Safety should now be considered as an

intrinsic plant property rather than a responsive action, and the plant needs to be

exible to be able to respond quickly to changes in the market. Last but not least,

new concepts will be required to provide a basis for sustainable future develop-

ments, that is, the use of renewable resources and processes based on green

solvents. As a result of this changing focus, a shift toward a multidisciplinary

approach can be observed.

For PRE this implies the combination of several disciplines such as polymer

chemistry, thermodynamics, characterization, modeling, safety, mechanics, phys-

ics, and process technology. PRE problems are often of a multi-scale and multi-

functional nature to achieve a multi-objective goal. One particular feature of PRE

is that the scope ranges from the micro scale on a molecular level up to the macro

scale of complete industrial systems. PRE plays a crucial role in the transfer of in-

formation across the boundaries of dierent scale regions and to provide a compre-

hensive and coherent basis for the description of these processes [19].

As depicted in Figure 1.4, there is a direct link between time and size scale, from

which it is obvious that the micro and macro scales are not related to the same

time scale [20]. As an example, molecular dynamics calculations are addressing a

time scale in the order of femto- to nanoseconds, whereas process system integra-

tion evolves on the scale of years. Engineers have traditionally been working at the

meso scale, which is represented by the middle portion of Figure 1.4, using phe-

1980 1990 2000 2010

Integrated heat recovery

Coal, Oil Natural gas Renewable feedstock

Plant operation Integrated and inherent safety

Capacity Quality control Flexible production

Water Air RecyclingClean processes Green solvents

From empiricism to strategy Multidisciplinarity

Optimization Intensification

Energy

Raw material

Safety

Market

Pollution control

Scientific methodology

Process

Less energy demanding processes

Fig. 1.3. Changing priorities in industrial chemical engineering research.


nomenological and continuum models. Today these limits are pushed in two direc-

tions, both toward a more fundamental understanding and at the same time to-

ward a more global scale. In the past, the micro-region has traditionally been

the domain of physicists and chemists, whereas the macro-region has been the

eld, rather, of process or plant engineers. Today, it becomes obvious that only us-

ing a multidisciplinary, parallel, and synergetic approach can lead to successful de-

velopments. Polymer reaction engineering will play an essential role as the core

and the coordinator of this complex process.

1.4

Toward Integrated Polymer Reaction Engineering

As will be obvious from the foregoing discussion, PRE is composed of many disci-

plines all linked together. These disciplines can be either mature or emergent, but

they have a common gateway (see Figure 1.5). Although there is not necessarily a

direct connection between them, there exists a common core in which the dierent

disciplines make their own specic contribution to a general objective.

The frontiers in PRE are determined by what we know, understand, and are able

to quantify, and these frontiers are moving with growing knowledge, competences,

and experience. Eorts to push these limits will induce innovative developments

leading to emerging technologies and products, and will also strengthen the multi-

disciplinary approach. In general terms, PRE can be dened as the science that

Time scale

Size scale

Years

Days

Minutes

Milliseconds

Nanoseconds

Picoseconds

Femtoseconds

1 10 100 1m 1mm 1m 1km

Atomic level Fundamental

Quantum techniquesQuantum chemistry

Molecular level Elementary reactionsMolecular modeling

Chemical equilibrium

Phenomenological Models

Microstructure

Continuum Models

Heterogeneous

Engineering designProcess models

System integrationEnvironmental, Global

modeling

Fig. 1.4. Activities in PRE with their corresponding time and size scales.

1.4 Toward Integrated Polymer Reaction Engineering 7

brings molecules to an end-use product. We can either consider it like a black box

(Figure 1.6) or we can try to dene the interconnected disciplines that compose

this black box (Figure 1.7). Provided the required product properties can be met,

we expect that sustainability is the common denominator for all the disciplines in-

volved in this process.

The process of transforming raw materials into valuable end-use products is not

a one-way procedure but rather an iterative process in which we try to optimize all

the parameters involved. The selection of the proper chemistry and technology

should include an evaluation of environmental, safety, and economic parameters.

Moreover, questions regarding the possible use of renewable resources and mini-

mizing the energy requirement will have to be answered. Dening PRE in this

manner appears to be very close to the procedure of life cycle analysis (LCA) [21].

Polymer ReactionEngineering

(PRE)

Polymer chemistryReaction kinetics

Process integrationoptimization

Inherent safety

EnvironmentRecycling, Disposal

Novel processes

New products

MaterialsApplication

Modeling andsimulation

Thermodynamics

Novel processes

Post-reactionprocesses

Measurement and control

Materials sciences

Nano-, Micro-Bio-

Fig. 1.5. The expanding sphere of polymer reaction engineering.

Polymer Reaction EngineeringRaw materials End use product

Fig. 1.6. PRE as a black box process.


Life cycle analysis is a tool assisting decision making in the engineering process.

LCA includes the information on the history of the materials used, and the dif-

ferent process and raw material alternatives, as well as the nal product require-

ments. LCA is an instrument driven by environmental considerations against a

background of technical and economic specications, and involves the so-called 3-

P concept (people, planet, and prot). The LCA-based PRE methodology (Figure

1.8) [22] leads to an optimization of all the parameters involved and a reduction of

the costs. This seems to be contradictory at rst sight, but integrating all the as-

pects often leads to cost reductions. In our view, the use of this approach will lead

to a sustainable integrated PRE.

1.5

The Disciplines in Polymer Reaction Engineering

The dierent disciplines involved in PRE can be represented using the academia

industry dichotomy (Figure 1.9). The interests of the two types of players are not

identical: the dierences are similar to the dierences in their mission statements.

Nevertheless, we can observe that a great overlap is present in the middle zone,

Integrated PRE

Polymer chemistryReaction kinetics

Process integrationoptimization

Inherent safety

EnvironmentRecycling, Disposal

Novel processes

New products

MaterialsApplication

Modeling andsimulation

Thermodynamics

Novel processes

Post-reactionprocesses

Measurement and control

Materials sciences

Nano-, Micro-Bio-

Raw materials

Energies

Needs

Laws

Economy

Sustainability

Renewable

Products

Profit

Satisfaction

Knowledge

Fig. 1.7. The integrated approach for sustainable PRE.


where interests, tools, and knowledge are similar, thus providing a strong basis for

partnership.

As stated above, PRE is composed of a large number of disciplines, which are

described in more detail in the following chapters of this handbook. These disci-

plines are interconnected by a synergetic and multidisciplinary approach, and com-

processing

synthesis

raw material

product use

recycling

wastemanagement

Specification

- technical- economic- ecologic- safety

Balances

- energy- material- emission- waste- sewage

Evaluation leads to closedloop assessment of costs

Fig. 1.8. Life cycle analysis of parts, methods, products, and systems.

Academia

Industry

Safety

Processmodeling

Molecular modeling

Reactor design

Measurementand control

Fundamentalkinetics

Thermodynamics

Qualityassurance

Noveltechnologies

Marketeconomics

Polymer chemistry

Polymer physics

Environment

Appliedmodeling

Fig. 1.9. Overlap of industrial and academic disciplines.


mercial products are the nal achievement resulting from this methodology. This

could be expressed by an orthogonal representation (Figure 1.10) where polymer

sciences are linked with engineering sciences. Every type of polymerization will

have its own specic features, models, and engineering aspects involved. From Fig-

ure 1.10 it will be obvious that only teamwork, bringing together several elds of

expertise, can lead to the nal objective.

1.5.1

Polymerization Mechanisms

Polymerization reactions can be classied depending on the reaction mechanism

involved and can be either step-growth or chain-growth. These mechanisms dier

basically with the time scale of the process. In step-growth polymerization (like

polycondensation), the polymer chain growth proceeds slowly from monomer to

dimer, trimer, and so on, until the nal polymer size is formed at high monomer

conversions. Both the chain lifetime and the polymerization time are often in the

order of hours. In chain-growth polymerization (like ionic or free-radical polymer-

ization), macromolecules grow to full size in a much shorter time (seconds being

the order of magnitude) than required for high monomer conversion. High molec-

ular weights are already obtained at low monomer conversion, which is in great

contrast to step-growth polymerizations. Also, unlike step-growth polymerization,

chain-growth polymerization requires the presence of an active center.

Condensation polymers are the result of a condensation reaction between mono-

mers, with or without the formation of a condensation by-product (Chapter 3). Ex-

amples of polymers produced by condensation are polyamide[6.6], (Nylon 6,6) the

result of the intermolecular condensation of hexamethylenediamine and adipic

acid, and polyamide[6], (Nylon 6) which is the product of intramolecular condensa-

tion of a-caprolactam. This type of reaction is generally sensitive to thermodynamic

equilibrium and requires the removal of the by-product, which is often volatile.

Polycondensation

Fig. 1.10. Product-driven PRE, based on an orthogonal

relationship between science and engineering.


The polymers produced by condensation reactions can be either linear or non-

linear, depending on the number of functional groups per monomer. The polymer-

ization process can be performed in bulk (liquid or solid state) or as an interfacial

polymerization.

Free-radical polymerization (FRP) can be performed homogeneously (in bulk, so-

lution, or suspension; Chapters 4 and 5) or heterogeneously (emulsion, precipita-

tion; Chapter 6). The active site is always a radical that can be unstable (classical

FRP) or stabilized as in pseudo-living FRP. Radicals can be formed by the homo-

lytic bond rupture of initiators (molecules sensitive to homolytic cleavage, such as

peroxides, photosensitive molecules, or bisazo compounds) or by complex mecha-

nisms creating radicals from monomer units using thermal or high-energy

sources, such as X-rays, g-irradiation, or UV. This type of polymerization usually

comprises several steps: initiation, propagation, various transfer mechanisms,

and termination.

In ionic polymerizations a cation or anion is the active site (Chapter 7). A heter-

olytic process leads to charged parts of molecules that can induce the polymeriza-

tion by nucleophilic or electrophilic processes. These reactions generally evolve at

low temperatures (even as low as 120C) due to the high reactivity of ions. Also,they are very sensitive to impurities present in the monomer or solvent. These re-

actions are not always terminated, so lead to living polymerization. This process is

often used to build tailor-made copolymers.

Coordination polymerizations require a transition metal catalyst (Chapter 8). Poly-

olens are often produced by this kind of reaction where the catalyst (Ziegler

Natta, for example) acts as the active site but also as the steric regulator, which

makes it possible to build polymers with a dened tacticity. Nowadays a great re-

search eort is devoted to the synthesis of new transition metal-based catalysts,

such as metallocenes, to produce new products.

1.5.2

Fundamental and Engineering Sciences

Apart from the various polymerization mechanisms involved, a large number of

other disciplines will have to be involved, according to the matrix depicted in

Figure 1.10.

Thermodynamics is essential to understand the physicochemical properties of

the individual reactants, solvents, and products involved (Chapter 2). Also, it pro-

vides information on the interaction between the various components present in

the reaction mixture, from which phenomena such as phase behavior and parti-

tioning can be derived. This information is usually accessible by using the appro-

priate equation of state for a given system studied. A close collaboration between

chemical physicists, chemists, and chemical engineers is required to take full ad-

vantage of this fundamental knowledge.

Polymer solutions (solid, bulk, solution, complex media) have to be characterized

by several specic analytical tools (Chapter 20). Techniques such as NMR, ESR,


electron microscopy, chromatography, electrophoresis, viscometry, calorimetry, and

laser diraction are widely used to determine polymer properties, often in combi-

nation. The main characteristics being analyzed are the chain length distribution,

degree of branching, composition, tacticity, morphology, particle size, and chemical

and mechanical properties. Polymer mechanics (Chapter 14) usually concerns the

nal product rather than the polymerization reaction. Nevertheless, as polymers

are usually judged on their end-use properties (Chapter 13), the nal product

needs specic and often customer-based analysis. This is described more speci-

cally for two application areas, namely the use of thermosets for coating applica-

tions (Chapter 16) and the production of polymeric bers (Chapter 17).

Measurement and control are indispensable to achievement of a robust and safe

process (Chapter 12). Since the early 1990s, a tremendous eort has been observed

in the development of new in-line analytical techniques, including spectroscopy

(UV, IR, Raman, laser, and so on), ultrasonic sensing, chromatography, and dirac-

tion or electrical methods. New control schemes appear where the reaction is per-

formed just below the constraint limits, independently of the reaction kinetics. All

these techniques tend to lead to safer and more robust processes while increasing

productivity and product quality at the same time.

Safety cannot be treated as a separate discipline as it is already integrated from

the early chemistry and process development (Chapter 11). Safety deals with a wide

variety of technological aspects with respect to the environment (water, air, soil,

and living species). However, economic aspects are usually taken into consider-

ation also. Modern process development intrinsically includes safety and environ-

mental aspects in all stages of the development.

Modeling is probably the tool of excellence for engineers (Chapter 9). It is

used to simulate the reaction and the process system in order to shorten the time

for development. It is based on models that can be physical or chemical, semi-

empirical or empirical, descriptive or more fundamental. To describe the develop-

ment of the molecular weight distribution upon reaction, moment methods or

equations based on population balance are often used.

Scaleup is a widely used term to dene the methodology that allows scaling up

of a process from small to larger scale (Chapter 10). Often the scaleup process be-

gins with a scaledown approach in order to have reliable and representative equip-

ment already at the laboratory scale. Scaleup is always dependent on the system

studied and requires a proper understanding of the performance of process equip-

ment involved at dierent scales. In polymer reaction engineering, heat transfer

and mixing can be considered as two major issues in this perspective. Modern

computing techniques such as computational uid dynamics and process simula-

tion become more and more important in the optimization of process parameters

and the equipment hardware.

Volatile organic compound (VOC) content in the nal product is related to prod-

uct properties and legislation (FDA approval in the USA, for example). All the pro-

cesses aiming to lower the residual VOC content in the product are denoted as re-

movable (Chapter 18). These processes can dier from each other, depending on


the techniques involved. Devolatilization, post-process reaction, and extraction are

some of the methodologies employed for this purpose.

Stability and degradation of polymers (Chapter 15) become relevant especially

during post processing or moulding processes. Temperature, oxidation and me-

chanic stresses are the main contributors to product degradation.

Currently, there is a strong emphasis on the synthesis of novel functional poly-

mers shaped on a nano scale (Chapter 19) and the development of sustainable

production processes (Chapter 21). The latter includes process intensication as a

methodology, the use of green solvents, and the use of renewable resources.

Many of the new processes under development are focusing on one or more of

these topics, for which the use of supercritical uids is currently being imple-

mented on an industrial scale.

1.6

The Future: Product-inspired Polymer Reaction Engineering

Innovation times in industry have shown a steady decrease since the 1970s. Classic

thinking is that process development becomes increasingly important as industry

matures [23]. This is due to the fact that in an early phase of the lifetime of an in-

dustry, when product concepts are still being created, the rate of product innova-

tion exceeds the rate of process innovation. This period continues until a dominant

design has emerged and opportunities for radical product innovation

polymer reaction engineering

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