8/11/2019 385622007

1/10

Handbook of Polymeric Foam sand Foam Technology2nd Edition

Edited byDaniel Klempner and Vahid Sendijarevic

With contributions byR.M. Aseeva, K. Ashida, J.K. Backus, T. Baumann, R. Broos,L. Domeier, C.V. Gupta, J.R. Harper, R. Herrington, P.T. Kelly,D. Klempner, P. Kn aub, R.F. Mausser, W. Nicholson, C .B. Park,C.P. Park, J.H. Saunders, V. Sendijarevic, F.A. Shutov, K.W. Suh,D. Visco, F. Xing

HANSERHanser Publishers, MunichHanser Gardener Publications, Inc., Cincinnati

8/11/2019 385622007

2/10

Contents

Preface IX

1 Introduction 11.1 References 4

2 Fundam entals of Foam Formation 52.1 Introduction 52.2 Fundam ental Principles of Foam Form ation 6

2.2.1 Bubble Formation 62.2.2 Bubble Growth 82.2.3 Bub ble Stability 9

2.3 Supporting Eviden ce from Specific Foam Systems 112.3.1 Thermop lastic Foam s 112.3.2 Polyurethane Foam s 122.3.3 Cellular Rub ber 13

2.4 Summ ary 132.5 References 14

3 Cellular Structure and Properties of Foamed Polymers 173.1 Introduction 173.2 Porous and Cellular Systems 17

3.2.1 Statistical M eaning of the Concept of a Cell 173.2.2 Term inology 183.2.3 Basic Relationsh ips 193.2.4 Packing Types 20

3.3 Open- and Closed-Cell Foam ed Plastics 223.3.1 General Problems 223.3.2 Open Cells and Density 233.3.3 Reticulated Foam s 24

3.4 Density of Foam ed Polyme rs 243.4.1 Classification 243.4.2 Density and Cell Size 253.4.3 Density and W all Thickness 26

3.5 Cell Shape of Foamed Polymers 283.5.1 Cell Shape Models 283.5.2 12- and 14-Hedrons 283.5.3 Anisotropy of Cell Shapes 30

3.6 Cell Size of Foamed Polymers 333.6.1 Methods of Estimation 333.6.2 Cell Size and Nu m ber of Cells 343.6.3 Cell Size and W all Thickn ess 343.6.4 Microcells 353.6.5 Cell Size and Physical Properties 37

3.7 Models of Cellular Structure and Calculation of Mechan ical Propertiesof Foam ed Polymers 38

8/11/2019 385622007

3/10

XII Contents

3.7.1 Flexible Foamed Polymers 383.7.2 Rigid Foamed Polymers 39

3.8 Cellular Structure and Therm al Conductivity of Foam ed Polym ers 40

3.8.1 Thermal Conductivity of the Polymer Phase 413.8.2 Thermal Conductivity of the Gas Phase 413.8.3 Radiative Therm al Con ductivity 443.8.4 Convective Thermal Conductivity 453.8.5 Effects of Variables on the Thermal Con ductivity 46

3.9 General Concepts 473.9.1 Three Generations of Polym er Foam s 473.9.2 Six Structural Levels 483.9.3 Quantitative Param eters of Cellular Structure 493.9.4 Technological Conce pts 50

3.9.5 Advantages of Foamed Polymers 513.10 References 52

4 Flexible Polyurethan e Foam s 554.1 Introduction 55

4.1.1 Applications 554.1.2 Markets 56

4.2 Basic Chem istry 574.2.1 The Polymerization Reaction 594.2.2 The Gas-Producing Reaction 60

4.2.3 Foam Recipe Com ponents 614.3 Foam Mo rphology 774.3.1 Review of Current Concepts 774.3.2 Mo del for Flexible Foam Formation 84

4.4 Preparation of Flexible Foam 844.4.1 General Requirements 854.4.2 Laboratory-Scale Cup-Foam ing 864.4.3 Laboratory Box-Fo ams 864.4.4 Mach ine-Made Foam 874.4.5 Mixing Heads 88

4.4.6 Com mercial-Scale Processes 894.5 Foam Physical Properties 944.5.1 Foam Density 954.5.2 Load Bearing 954.5.3 Airflow 974.5.4 Cell Size 974.5.5 Com pression Set 984.5.6 Tension Properties 994.5.7 Tear 994.5.8 Resilience 100

4.6 Slabstock Foam s 1004.6.1 Slabstock Chemistry 1004.6.2 Alternative Blowing Agent Developm ents 1004.6.3 High Load Bearing Foam s 1014.6.4 High Resilience Foams 102

8/11/2019 385622007

4/10

8/11/2019 385622007

5/10

XIV Contents

6.2.2 Kine tics and M echan isms of Cyc lotrimerization 1486.2.3 Relative Catalytic Ac tivity 156

6.3 Preparation of Modified Polyisocyanurate Foams 160

6.3.1 Urethane-Mo dified Polyisocyanurate Foam s 1606.3.2 Oxazolidone-Modified Polyisocyanurate Foam s 1756.3.3 Am ide-Mod ified Polyisocyanurate Foam s 1786.3.4 Carbodiimide-Modified Polyisocyanurate Foam s 1786.3.5 Imide-Modified Polyisocyanu rate Foam s 179

6.4 Ap plications 1806.4.1 Com posite Foam Boards 1806.4.2 Flam e-Retardant Seam less Insulation [61] 1816.4.3 Building Insulation 1826.4.4 Chemical and Petroche mical Plant Insulation 183

6.4.5 High -Rise Bu ilding W alls 1836.4.6 Che mical-Resistant Floats 1836.4.7 Cryogenic, Petrochemical, and Solar Energy

Applications 1836.4.8 High ly Resilient Flexible Polyurethane Foam s 184

6.5 References 184

7 Polystyrene and Structural Foam 1897.1 Introduction and Gen eral Description 189

7.1.1 Nom enclature 190

7.2 Chemistry and Preparation 1907.2.1 Theory of the Expansion Process 1917.2.2 Blow ing Agent Selection 193

7.3 Properties and The ir Relation to Structure 1957.3.1 Test M ethods 1957.3.2 Properties of Com mercial Produ cts 1957.3.3 M echan ical Properties 1997.3.4 Thermal Properties 2047.3.5 Mo isture Resistance 2067.3.6 Electrical Properties 207

7.3.7 Environmental Aging 2077.3.8 Other Properties 2077.4 Com mercial Production and Processing 208

7.4.1 Manufacturing Process 2087.4.2 Com mercial Products and Processes 212

7.5 App lications 2147.5.1 Cushioning 2157.5.2 Therm al Insulation 2167.5.3 Packaging 2177.5.4 Structural Componen ts 219

7.5.5 Marine Applications 2197.5.6 Electrical Insulation 2197.5.7 Space Filling and Seals 2197.5.8 Other Uses 2207.5.9 Energy Considerations in Foam Insulation 220

8/11/2019 385622007

6/10

Contents XV

7 5 1 Health and Safety Factors 2247.6 References 225

8 Polyolefin Foam 2338.1 Introduction 2338.2 Chem istry and Preparation 234

8.2.1 Foam Expansion with a Physical Blowing Agent 2378.2.2 Foam Expansion with a Chem ical Blowing Agent 248

8.3 Properties and Their Relation to Structure 2628.3.1 Properties of Com mercial Products 2668.3.2 Relationships Between Structure and Properties 267

8.4 Com mercial Production and Processing 2758.4.1 Extrusion Processes 275

8.4.2 Processes for Manufacturing Moldable Polyolefin Beads 2788.4.3 Cross-Linked Polyolefin Foam Sheet Processes 2818.4.4 Cross-Linked Polyolefin Foam Bun Stock Processes 286

8.5 Applications 2888.5.1 Fabrica tion 2888.5.2 Major Applications 289

8.6 References 293

9 PVC Foams 3019.1 Introduction 301

9.2 Characteristics of PV 3039.2.1 PVC Structures 3049.2.2 Structure Changes During Processing 3059.2.3 Influence of PV Fusion on Physical Properties 305

9.3 Formulation Techno logy 3059.3.1 Overview of Formulas for PVC Foam 3059.3.2 Effects of Formulation Ingredients on the Foam ing Process and

Properties of Foam ed Products 3089.3.3 Use of Recycled PVC in Foam Formulations 3179.3.4 Design of Experiment DOE) for Foam Form ulation Developm ent 318

9.4 Processing Technology 3209.4.1 Extrusion of PV Foams 3219.4.2 Injection Molding of PVC Foam s 3289.4.3 Foam ing of PVC at Atmospheric Pressure 3299.4.4 Microcellular PVC Foam s 3319.4.5 PVC /Wood Flour Composite Foams 334

9.5 Mechanical Property Analyses and Test Standards 3359.5.1 Mechanical Properties 3369.5.2 ASTM and ISO Standards 340

9.6 References 341

1 Epoxy Foams 34710.1 Introduction 34710.2 Epoxy Chem istry and Formulations 34710.3 Blowing or Foam ing Agents and Processes 349

8/11/2019 385622007

7/10

8/11/2019 385622007

8/10

Contents XVII

12.2.3 Preparation 38412.3 Prope rties and Their Relationship to Structure 384

12.3.1 Structural Features 384

12.3.2 Physical Properties 38412.4 Com mercial Production and Processing 38612.4.1 Metering 38612.4.2 Mixing 38612.4.3 Dispen sing 38712.4.4 Equipm ent Selection 388

12.5 Applications 38812.5.1 Foam App lications 38812.5.2 Forms of Foam 38812.5.3 Features of Silicone Produ cts 388

12.5.4 Areas of Application 38912.6 References 389

13 Fluoropolymer Foams 39113.1 History and Introduction 39113.2 Chem istry and Physics of Foam Preparation 392

13.2.1 Nucleation and Bubb le Growth 39313.3 Prope rties and Their Relation to Cell Structure 397

13.3.1 Physical Properties 39713.3.2 Thermal Properties 399

13.3.3 Specific Hea t 40013.3.4 Electrical Properties 40013.4 Com mercial Production and Processing 402

13.4.1 Foaming of FEP and PFA Resins 40213.4.2 Foaming of Fluoroelastomer Resins such as Viton) 40313.4.3 Expansion of PTF E Resin 404

13.5 App lications 40513.6 References 406

14 W ood Flour Com posite Foams 409

14.1 Introduction 40914.1.1 Background on Polymeric Com posites 40914.1.2 Natural Fibers and Their Properties 41014.1.3 Plastic/Wood Flour Com posite Foam s 413

14.2 Major Issues in Development of PW Foams 41514.2.1 Thermal Degradation of Na tural Fibers 41614.2.2 M oisture Content and Volatile Em issions from Natural Fibers 41814.2.3 Dispersion of Natural Fiber and Fiber-Matrix Bond ing 42014.2.4 Processing Difficulties Due to Increased Viscosity 420

14.3 Phase Changes in Foam ing of PW C 421

14.3.1 Changes in Phase M orphology of the Extrudate DuringM icrocellular Foam ing and Fine-Celled PW C Foam ing 42114.3.2 Polymer/Gas Solution Formation 42214.3.3 Cell Nucleation 42314.3.4 Cell Grow th Control 424

8/11/2019 385622007

9/10

X V III Contents

14.4 Experiments and Discussion 42614.4.1 Effects of Vo latile Em issions from W ood Flour During

Extrusion Processing 427

14.4.2 Foam ing Experimen ts with Varying Content of Extractives 43114.4.3 Critical Processing Tem perature in Extrusion Processingof PW C Foams 434

14.4.4 Foam ing with Various CB As 43914.5 Conclusions 44214.6 References 443

15 Phenolic Foams 44715.1 Chem istry and Foam Formation 447

15.1.1 Phenolic Resins 447

15.1.2 Crosslinking of Phenolic Resins 44915.1.3 Foam Form ation 45015.1.4 Redu ction in Corrosivity of Phenolic Foam 452

15.2 Prop erties and The ir Relation to Structure 45215.3 Com mercial Production and Processing 45415.4 App lications 45515.5 References 455

16 Flame Retardancy of Polymeric Foams 45716.1 Introduction 457

16.2 The Com bustion of Polyme ric Foam s 45816.2.1 Flame Com bustion of Polymeric Foams 45816.2.2 Smo ldering Com bustion of Polymeric Foam s 46016.2.3 Filtration Com bustion of Gases in Polymeric Foam s 462

16.3 Test M ethods and Fire Safety Classification Param eters 463of Foam ed M aterials for the Assessment of Fire Hazards 46316.4 Recent Adv ances in Flame Retardancy of Polymeric Foam s 468

16.4.1 The Development of Foam s Based on InherentlyThermally Stable and Flame Retardant Polymers 468

16.4.2 Chem ical and Physical Modification of Polymeric Foams 470

16.4.3 Additive Flame Retardants 47116.5 References 475

17 Syntactic Polymer Foam s 47917.1 Introduction 47917.2 Hollow Sphere Fillers 480

17.2.1 Gen eral Information 48017.2.2 Glass Microspheres 48017.2.3 Polymeric M icrospheres 48117.2.4 M iscellaneous Other M icrospheres 48217.2.5 M acrospheres 482

17.3 Syntactic Foam Processing 48217.3.1 General Considerations 48217.3.2 Rheo logy of Syntactic M ixtures 48317.3.3 Casting and Mo lding Com positions 483

8/11/2019 385622007

10/10

Contents XIX

17.3.4 Regulating the Apparent Density 48417.3.5 Microsphere Space Factors and Packing 485

17.4 Syntactic Foam Production 487

17.4.1 Epoxy Syntactic Foam s 48717.4.2 Oligoester Syntactic Foam s 48817.4.3 Pheno lic Syntactic Foams 48817.4.4 Organosilicone Syntactic Foam s 48917.4.5 Polyimide Syntactic Foam s 48917.4.6 Carbonized Syntactic Foam s 48917.4.7 Syntactic Prepregs 49017.4.8 Miscellaneous Syntactic Foam s 491

17.5 Phy sical Properties of Syntactic Foam s 49117.5.1 Strength Properties 491

17.5.2 W ater Absorption and Resistance to Hydrostatic Pressure 49417.5.3 Therm al Properties 49617.6 Recent Developm ents and M ain App lications 497

17.6.1 Sub-Sea and Shipbu ilding Applications 49717.6.2 Structural Ap plications 50017.6.3 Aerospace Applications 50217.6.4 Other Applications 503

17.7 References 503

18 Blowing Agents for Polymeric Foams 505

18.1 Introduction 50518.2 Classification 50518.3 Chem ical Blowing Agents 507

18.3.1 Main Cha racteristics 50718.3.2 Inorganic Blowing Agents 50918.3.3 Organic Blowing Agen ts 51118.3.4 Blowing A gents that Liberate Gases as a Result of Chem ical

Interaction between the Com ponents 53218.3.5 Practical Gu ide for Selection of CB As 536

18.4 Physical Blowing Agents and Environm ental Problems 539

18.4.1 M ain Cha racteristics 53918.4.2 Vo latile Liquids 54018.4.3 Solid Blowing Agen ts 546

18.5 Gases 54618.6 Nucleazites 54618.7 References 547

Appendix 1 549Letters of the Rom an Alphabet 549Capital Greek Letters 550

Lower Case Greek Letters 551

Appendix 2 552Conversion Factors between English and S.I. Units for QuantitiesUsed in Describing the Ph ysical Properties of Foams 552