Front Cover

Recycling of Polyurethane Foams

Copyright Page

Contents

List of Contributors

1 Introduction to Polymer and Their Recycling Techniques

1.1 Introduction of Plastics and Their Classification

1.2 Classification of Polymers

1.3 Recycling of Thermoplastics Is Possible but not With Thermosets. Why?

1.4 Polymerization Reactions

1.5 Economic and Environmental Impact of Plastic Waste

1.6 Economic Issues Relating to Recycling

1.7 Various Thermoplastics and Their Applications

1.7.1 Polyolefins

1.7.2 Vinyl Polymers

1.7.3 Polystyrenes

1.7.4 Acrylate and Methacrylate Polymers

1.7.5 Polyamide (i.e., Nylons)

1.7.6 Polycarbonates

1.7.7 Celluloid

1.7.8 Linear Polyester

1.7.9 Polyfluorethane

1.7.10 Polyacetals

1.7.11 Polysulfones

1.7.12 Polyphenylene Sulfide

1.7.13 Modified Polyphenylene Oxide (PPO)

1.8 Various Thermosetting Plastics

1.8.1 Unsaturated Polyester

1.8.2 Phenol Formaldehyde Resins

1.8.3 Melamine Resins

1.8.4 Polyepoxides

1.8.5 Polyimide

1.8.6 Polyurethane

1.8.7 Polyorganosiloxanes

1.9 Systems for Plastic Recycling

1.10 Recycling of Thermoplastics

1.10.1 Size Reduction and Cleaning

1.10.2 Further Separation

1.10.3 Processing/Remelting to Make Products

1.11 PET Bottle/Container Recycling Process

1.12 PU Recycling Processes

1.12.1 Mechanical Recycling

1.12.2 Chemical Recycling

1.13 Recycling of Thermoset Plastics

1.14 Recycling and Reuse of Elastomeric Materials

1.14.1 Incineration

1.14.2 Pyrolysis

1.14.3 Grinding of Vulcanized Rubber Waste

1.14.4 Devulcanization

1.14.5 Applications of Waste Rubber

1.15 Challenges and Opportunities for Improving Plastic Recycling

1.16 Conclusions

References

Further Reading

2 Polyurethane Foam Chemistry

2.1 History

2.2 Raw Materials

2.3 Isocyanates

2.4 Polyols

2.5 PU Foams

2.5.1 Flexible Slabstock

2.5.2 Flexible Cold Cure Molding

2.5.3 Rigid Foams

2.5.4 Microcellular or Footwear Foams

2.5.5 Elastomeric Applications

2.6 Blowing Agents

2.6.1 Physical Blowing Agents

2.6.2 Chemical Blowing Agents

2.6.3 Mixed Physical/Chemical Blowing Agents

2.7 Manufacturing of PU Foams

2.7.1 Slabstock Method

2.7.2 Molding Method

2.8 Properties of PU Foams

2.8.1 Foam Is a Good Air Sealant

2.8.2 Closed-Cell Foam Has Very High Resistance Toward Water Vapor Permeation

2.8.3 Closed-Cell Foam Resists Damages From Short-Term Wet Conditions

2.8.4 Binding Strength of Foam

2.8.5 Structural Advantages of Foams

2.9 Thermal Conductivity

2.9.1 Thermal Conductivity and Thermal Resistance of Insulating Materials

2.9.2 Thermal Conductivity of Rigid PU Foam (PUR/PIR)

2.10 The R-Value of PU Foam Is Higher Than Other Types of Insulations

2.11 Mechanical Properties of PU Foams

2.11.1 Density

2.11.2 Compressive strength σ·m

2.11.3 Continuous Compressive Stress σ c (Compressive Creep)

2.11.4 Tensile Strength Perpendicular to Faces σmt, Shear Strength, and Bending Strength σb

2.11.5 Flammability of PU Foams

2.11.6 PU Foam Manufacturers in India

2.12 Conclusion

2.12.1 Mechanical Recycling

2.12.2 Chemical Recycling

References

3 Degradability of Polymers

3.1 Thermal Degradation

3.1.1 Initiation

3.1.2 Propagation

3.1.3 Termination

3.2 Chemical Degradation

3.2.1 Hydrolysis

3.2.2 Alcoholysis

3.2.3 Acidolysis Process

3.2.4 Glycolysis Process

3.2.5 Aminolysis

3.3 Mechanical Degradation

3.3.1 Regrinding

3.3.2 Adhesive Pressing

3.3.3 Compression Molding

3.3.4 Injection Molding

3.4 Photodegradation

3.5 Biodegradation

3.5.1 High-energy radiation degradation

3.5.2 Ultrasonic Wave Degradation

3.6 Conclusion

References

Further Reading

4 Introduction to Mechanical Recycling and Chemical Depolymerization

4.1 Mechanical Depolymerization

4.2 Chemical Depolymerization

4.3 Summary

References

5 Mechanical Recycling via Regrinding, Rebonding, Adhesive Pressing, and Molding

5.1 Introduction

5.2 Mechanical Recycling of PU Foams

5.2.1 Grinding and Powdering

5.2.2 Rebonding

5.2.3 Adhesive Pressing

5.2.4 Compression Molding, Injection Molding, and Extrusion

5.3 Summary

References

6 Chemical Depolymerization of Polyurethane Foams via Glycolysis and Hydrolysis

6.1 Introduction

6.2 Glycolysis of Rigid and Flexible PU Foams

6.2.1 Double Recovery Method

6.2.2 Microwave-Assisted Techniques

6.3 Glycolysis Technology

6.3.1 Analytical Techniques

6.4 Applications

6.5 Comparison of Glycolysis With Hydrolysis

6.5.1 Hydrolysis

6.6 Conclusion

References

7 Chemical Depolymerization of Polyurethane Foam via Ammonolysis and Aminolysis

7.1 Introduction

7.2 Aminolysis of PU Foam

7.3 Ammonolysis of PU Foam

7.4 Conclusion

References

8 Chemical Depolymerization of Polyurethane Foams via Combined Chemolysis Methods

8.1 Introduction

8.1.1 Physical Recycling

8.1.2 Chemolysis of PU Foam

8.1.2.1 Hydrolysis of PU Foam

8.1.2.2 Alcoholysis of PU Foam

8.1.2.3 Acidolysis of PU Foam

8.1.2.4 Aminolysis of PU Foam

8.1.2.5 Glycolysis of PU Foam

8.2 Combined Chemolysis of PU Foam

8.2.1 Hydroglycolysis

8.2.1.1 Mechanism for Hydroglycolysis Reaction

8.2.2 Glycolysis–Aminolysis

8.2.3 Aminolysis–Hydrolysis

8.3 Advantages and Disadvantages of Combined Chemolysis

8.4 Combined Chemolysis in Comparison to Other Recycling Methods of PU Foams

8.4.1 Physical Recycling

8.4.1.1 Regrind or Powdering

8.4.1.2 Adhesive Pressing/Particle Bonding

8.4.1.3 Pyrolysis

8.4.2 Chemical Recycling

8.4.2.1 Glycolysis

8.4.2.2 Methanolysis

8.4.2.3 Aminolysis

8.4.2.4 Hydrolysis

8.4.3 Combined Chemolysis

8.5 Comparison Between Combined Chemolysis and Conventional Chemolysis

8.6 Conclusions

References

Further Reading

9 Life Cycle Analysis of Polyurethane Foam Wastes

9.1 Introduction—Theoretical Background

9.1.1 Life Cycle Assessment—Introduction

9.1.2 Procedural Steps of LCA

9.1.3 Use of LCA in Business and Policy-Making

9.1.4 Resources Inside of the EU to Help With LCA

9.2 LCA of Polyurethane Foam—Previous Studies

9.2.1 Comparative Assessment of LCA Scope Definition of Previous Studies

9.2.2 Comparative Assessment of LCI of Previous Studies

9.3 LCIA and Interpretation of Results of Previous LCA Studies

9.3.1 Environmental Impact Breakdown of PU Production Processes

9.3.2 Improvement of Environmental Performance of PU Production

9.4 Environmental Assessment of PU Recycling Routes

9.4.1 LCA of PU Recycling Routes

9.4.2 Conditions for Environmental Payback of PU Recycling

References

10 Construction Applications of Polyurethane Foam Wastes

10.1 Introduction

10.2 PU Foam Wastes

10.2.1 Recycled Lightweight PU Plaster Materials

10.2.2 Recycled Lightweight PU Mortar Materials

10.2.3 Recycled Lightweight PU Asphalt Materials

10.3 Eco-Friendly PU Coatings

10.4 Eco-Friendly PU Adhesives

10.5 Conclusions

References

Index

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