A comprehensive overview of the burgeoning field of biodegradable plastics
As the lasting impact of humanity’s reliance on plastics comes into focus, scholars have begun to seek out solutions to plastic litter. In Biodegradable Polymers in the Circular Plastics Economy, an accomplished team of researchers delivers a focused guide (1) to understand plastic degradation and its role in waste hierarchy besides recycling, and (2) to create and use biodegradable plastics where appropriate. Created preferably from renewable resources, these eco-friendly polymers provide an opportunity to create sustainable and lasting solutions to the growing plastic-driven pollution problem.
The broad approach to this handbook allows the authors to cover all aspects of these emerging materials, ranging from the problems present in the current plastics cycle, to the differences in type, production, and chemistry available within these systems, to end-of-life via recycling or degradation, and to life-cycle assessments. It also delves into potential commercial and policy issues to be addressed to successfully deploy this technology.
Readers will also find: - A thorough introduction to biodegradable polymers, focusing not only on the scientific aspects, but also addressing the larger political, commercial, and consumer concerns - Mechanisms of biodegradation and the environmental impact of persistent polymers - An in-depth discussion of degradable/hydrolysable polyesters, polysaccharides, lignin-based polymers, and vitrimers - Management of plastic waste and life cycle assessment of bio-based plastics
Biodegradable Polymers in the Circular Plastics Economy is the perfect overview of this complicated but essential research field and will appeal to polymer chemists, environmental chemists, chemical engineers, and bioengineers in academia and industry. The book is intended as a step towards a circular plastics economy that relies heavily on degradable plastics to sustain it.
Table of Contents
Preface xv
1 Biodegradable Polymers - A Tutorial for a Circular Plastics Economy 1
Jean-Paul Lange, Michiel Dusselier, and Stefaan De Wildeman
1.1 Context 1
1.2 Plastics in the Environment - Biodegradation and Impact of Litter 4
1.3 Biodegradable Polymers 5
1.3.1 Polyesters 6
1.3.2 Polysaccharides 8
1.3.3 Lignin 9
1.3.4 Vitrimers - Recyclable Thermosets 9
1.4 Beyond Biodegradation 10
1.4.1 Recycling and End-of-Life 10
1.4.2 Lca 11
1.4.3 Implementing the “New Plastics Economy” 11
1.5 Conclusions and Outlook 12
References 15
2 Fundamentals of Polymer Biodegradation Mechanisms 17
Ebin Joseph, Payman Tohidifar, Cara T. Sarver, Roderick I. Mackie, and ChristopherV.Rao
2.1 Introduction 17
2.2 Overall Scheme of Polymer Degradation 19
2.3 Biodegradation of Polysaccharides 20
2.3.1 Cellulose 20
2.3.2 Starch 22
2.4 Biodegradation of Polyamides 24
2.5 Biodegradation of Polyesters 24
2.5.1 Polylactic Acid 25
2.5.2 Poly(ε-caprolactone) 27
2.5.3 Polyhydroxyalkanoates 28
2.5.4 Polyethylene Terephthalate 29
2.6 Biodegradation of Hydrocarbons 36
2.6.1 Polyethylene 36
2.6.2 Polypropylene 38
2.6.3 Polystyrene 39
2.7 Biodegradation of Halogenated Polymers 40
2.7.1 Polyvinyl Chloride 41
2.7.2 Polytetrafluoroethylene 41
2.8 Biodegradation of Polyethers 41
2.8.1 Polyethylene Glycol 41
2.8.2 Polyurethane 42
2.9 Application of Biodegradation 43
2.10 Current Challenges and Future Prospects for Biodegradation of Plastics Wastes 44
2.a Detailed Mechanism of PET Hydrolysis 45
References 46
3 Plastic Pollution. The Role of (Bio)Degradable Plastics and Other Solutions 59
Lei Tian, Robert-Jan van Putten, and Gert-Jan M. Gruter
3.1 Introduction and Problem Definition 59
3.2 Sources of Macroplastics and MNPs 61
3.2.1 Mismanagement of Waste 61
3.2.2 Accidental Release 64
3.2.3 MNPs in Products 64
3.2.4 Degradation of Outdoor Objects 64
3.2.5 Wear (Tires, Clothing) 65
3.2.6 Waste and Wastewater Management (Water/Wind) 66
3.3 Impacts of Macroplastics and MNPs 67
3.3.1 Ecological Impact of Macroplastics (Entanglement and Ingestion) 67
3.3.2 Economic Impact of Macroplastics 67
3.3.3 Ecological Impacts of MNPs 68
3.3.3.1 Aquatic Environment 68
3.3.3.2 Terrestrial Environment 69
3.3.3.3 Atmosphere 69
3.3.4 Threat to Human Health 70
3.3.4.1 MNPs in the Human Food Chain 70
3.3.4.2 Plastic-Related Contaminants 70
3.3.4.3 Other Contaminants 70
3.3.5 Socio-Economic Impacts of MNPs 71
3.4 Plastic Biodegradability 71
3.5 Solutions 72
3.5.1 Cleaning Up 72
3.5.2 Waste Mitigation 73
3.5.3 Material Design 73
3.5.4 Bringing It All Together 73
3.5.5 Policies and Legislation 76
3.6 Conclusions 77
References 78
4 Tutorial on Polymers - Manufacture, Properties, and Applications 83
Gert-Jan M. Gruter and Jean-Paul Lange
4.1 Introduction 83
4.1.1 Today’s Petrochemical Industry 83
4.1.2 Today’s Bio-based Plastic Industry 85
4.1.3 Environmental and Climate Challenges 85
4.2 Production of Polymers 86
4.2.1 Addition Polymers 87
4.2.2 Condensation Polymers 88
4.2.3 Thermosets 90
4.2.4 Renewable Monomers 91
4.2.4.1 Oils-Based Monomers 91
4.2.4.2 Sugar-Based Monomers 92
4.2.4.3 Lignocellulose-Based Monomers 93
4.2.4.4 CO 2 -Based Monomers 95
4.3 Main Polymers Applications 95
4.3.1 Rigids 97
4.3.2 Films 98
4.3.3 Fibers 98
4.3.4 Foams 99
4.3.5 CASE (Coatings, Adhesives, Sealants, Elastomers) 100
4.3.6 Composites 102
4.4 End-of-Life and Biodegradation 103
4.4.1 Reuse and Recycling 103
4.4.2 Biodegradation 103
4.5 Conclusions 105
4.a Definitions: Biopolymer vs. Bio-based Polymer and Relation to Biodegradation 105
List of Polymers 107
References 108
5 Condensation Polyesters 113
Jules Stouten and Katrien V. Bernaerts
5.1 Introduction 113
5.2 Preparative Methods 114
5.3 Biodegradation of Polyesters 116
5.3.1 Hydrolytic Degradation 117
5.3.2 Enzymatic Degradation 118
5.4 Aliphatic Polyesters 119
5.4.1 Poly(alkylene dicarboxylates) 119
5.4.2 Poly(hydroxy acids) 120
5.4.3 Cyclic Sugar-Based Monomers 121
5.5 Semi-aromatic Polyesters 122
5.5.1 Poly(butylene adipate terephthalate) (PBAT) 122
5.5.2 Furanoate Copolymers 124
5.6 Cross-linked Polyesters 127
5.6.1 Multifunctional Alcohols or Carboxylic Acids 127
5.6.2 Incorporation of Functional Monomers 129
5.6.3 Cross-linking of Native Polyesters 130
5.7 Applications for Biodegradable Condensation Polyesters 130
5.7.1 Biomedical Applications 131
5.7.2 Agricultural Applications 132
5.7.3 Packaging Material 132
5.8 Polyester Recycling 132
5.9 Concluding Remarks 134
References 135
6 Polyhydroxyalkanoates (PHAs) - Production, Properties, and Biodegradation 145
Martin Koller and Anindya Mukherjee
6.1 Introduction 145
6.1.1 General Aspects of Biodegradation of Polymers 147
6.1.2 General Aspects of Microbial Synthesis of PHAs 148
6.1.3 Types and Properties of PHAs 150
6.2 Biosynthesis - Substrates and Strains 152
6.2.1 Principle Stoichiometry of PHA Biosynthesis 152
6.2.2 Biosynthesis of scl- and mcl-PHAs 154
6.2.3 Heterotrophic Feedstocks 155
6.2.4 Autotrophic Feedstocks 157
6.2.5 Syngas 158
6.2.6 Methane 158
6.2.7 Production Strains 160
6.3 Bioengineering: Bioreactor Design and Feeding Regime 163
6.3.1 Feeding Regime 163
6.3.2 Continuously Operated Bioreactors for Liquid Feed 164
6.3.3 Bioreactors for Gas Feed 166
6.3.4 Photo-reactors for CO 2 Feed 166
6.4 Downstream Processing for PHA Recovery 167
6.4.1 Classical Solvents 168
6.4.2 Halogen-Free Solvents 170
6.4.3 Supercritical Solvents 172
6.4.4 Recovery by Chemical and Mechanical Disintegration of Biomass 173
6.4.5 Biological PHA Recovery 175
6.5 End-of-Life Options: Recycling and Biodegradation of PHAs 176
6.5.1 Recycling 176
6.5.2 Incineration 178
6.5.3 Mechanistic Considerations of PHA Degradation 178
6.6 Biodegradation - Added Value for Selected Applications 181
6.6.1 Packaging 181
6.6.2 Hygiene/Care/Cosmetics 182
6.6.3 Medical - Drug Delivery 182
6.6.4 Other Applications 184
6.7 Conclusions 185
References 186
7 Ring-Opening Polymerization Strategies for Degradable Polyesters 205
An Sofie Narmon, Liliana M. Jenisch, Louis M. Pitet, and Michiel Dusselier
7.1 Introduction 205
7.2 Ring-Opening Polymerization Mechanisms 207
7.2.1 Cationic Ring-Opening Polymerization 207
7.2.2 Anionic Ring-Opening Polymerization 209
7.2.3 Coordination-Insertion Ring-Opening Polymerization 210
7.2.4 Enzymatic Ring-Opening Polymerization 211
7.3 ROP-Based Polyesters 211
7.3.1 Lactones 211
7.3.2 Thermodynamics and Kinetics 212
7.3.3 Functionalization 214
7.3.3.1 ROP of Functional Lactones 215
7.3.3.2 Post-polymerization Functionalization 215
7.3.3.3 Grafting 216
7.3.4 Four-Membered Lactones 216
7.3.4.1 β-Butyrolactone 218
7.3.4.2 Acid-Substituted β-Lactones (β-Malolactonate) 218
7.3.4.3 Alkoxy-Substituted β-Lactones 219
7.3.4.4 Alkene-Substituted β-Lactones 220
7.3.5 Five-Membered Lactones 221
7.3.5.1 γ-Butyrolactone 221
7.3.5.2 α-Angelicalactone 223
7.3.5.3 α-Methylene-γ-Butyrolactone 223
7.3.5.4 Ether γ-Lactones 225
7.3.6 Six-Membered Lactones 227
7.3.6.1 δ-Valerolactone 227
7.3.6.2 Unsaturated δ-Lactones 227
7.3.6.3 Ester-Substituted δ-Lactones 228
7.3.6.4 Ether δ-Lactones 230
7.3.6.5 Dilactones 232
7.3.7 Seven-Membered Lactones 236
7.3.7.1 ε-Caprolactone 236
7.3.7.2 Substituted and Functionalized ε-Caprolactone 238
7.3.7.3 Ether-ε-Lactones 241
7.4 Relations Between ROP Polymers and Degradability 242
7.5 Conclusion 246
7.6 Outlook and Recommendations 249
References 252
8 Recent Developments in Biodegradable Cellulose-Based Plastics 273
Karin Molenveld and Ted M. Slaghek
8.1 General Introduction 273
8.2 Cellulose 274
8.3 The Development of Cellulose Plastics 275
8.3.1 Cellulose Feedstock and Dissolving Pulp 276
8.3.2 Cellulose Derivatization 276
8.3.3 Cellulose Acetate and Cellulose Esters 277
8.3.4 Cellophane 279
8.3.5 Cellulose Fibers in Thermoplastic Formulations 280
8.4 Recent Developments in Thermoplastic Cellulose Derivatives 280
8.4.1 Characterization Methods for Lignocellulosic Biomass 281
8.4.2 Alternative Feedstocks for Dissolving Pulp and Production Routes 282
8.4.3 Ionic Liquids and Deep Eutectic Solvents for Cellulose Regeneration and Modification 283
8.4.4 New Derivatization Routes 284
8.4.5 Plasticizers 284
8.4.6 Mixed Cellulose Esters 285
8.4.7 Cellulose-Polymer Blends 286
8.4.8 (New) Properties and Processing Routes 287
8.4.9 New Applications 287
8.5 Biodegradation of Cellulose Derivatives 288
8.6 Conclusions 289
References 290
9 Ester Derivatives of Microbial Synthetic Polysaccharides 299
Hakyong Lee, Hongyi Gan, Azusa Togo, Yuya Fukata, and Tadahisa Iwata
9.1 Introduction 299
9.1.1 Background of Bio-Based Plastics 299
9.1.2 Polysaccharides 300
9.2 Zero Birefringence Property of Pullulan Esters 302
9.3 Bio-Based Adhesives from Dextran (α-1,6-Glucan) 304
9.4 Films and Fibers from Paramylon and Curdlan (β-1,3-Glucan) Esters 306
9.5 Polymerization of α-1,3-Glucan and Films of α-1,3-Glucan Esters 310
9.6 High-Performance Polysaccharide-Branched Esters 312
9.6.1 Cellulose-Branched Esters [14] 312
9.6.2 β-1,3-Glucan (Curdlan) Branched Esters [15] 314
9.6.3 α-1,3-Glucan-Branched Esters [16] 315
9.7 Enzymatic Esterification of Polysaccharides 316
9.7.1 Enzymes as Biocatalysts 317
9.7.2 Reaction Mechanism 318
9.7.3 Factors Influencing Enzyme Activity 319
9.7.4 Strategies for Efficient Biocatalyst Processes 320
9.7.5 Development Trend and Prospects 320
9.8 Biodegradation of Polysaccharide Ester 322
9.9 Summary 322
References 322
10 Biodegradable Lignin-Based Plastics 329
Yi-ru Chen and Simo Sarkanen
10.1 Lignocellulose Biorefineries 329
10.2 Macromolecular Lignin Configuration 331
10.3 Industrial Availability of Lignins 336
10.4 Compelling Traits in Physicochemical Behavior of Kraft Lignin Species 337
10.5 Kraft Lignin-Based Plastics 341
10.6 Tuning Strength and Production Cost of Plastics with High Kraft Lignin Contents 343
10.7 Ligninsulfonates (Lignosulfonates) 346
10.8 Laboratory Ball-Milled Lignins 348
10.9 Blend Configuration in Ball-Milled Lignin-Based Plastics Exemplifies the General Case 351
10.10 Lignin-Lignin Blends 355
10.11 Biodegradation of Kraft Lignin-Based Plastics 357
10.12 Alternative Formulations for Polymeric Materials Containing More than 50 wt% Lignin 359
10.13 Concluding Remarks 362
Acknowledgments 362
References 363
11 Design of Recyclable Thermosets 369
Bryn D. Monnery, Apostolos Karanastasis, and Louis M. Pitet
11.1 Introduction 369
11.1.1 Polymers and Plastics 369
11.1.2 Handling of Plastic Waste 370
11.1.3 Chemical Nature of Plastics 370
11.2 Design of Recyclable Thermosetting Polymers 372
11.2.1 Recyclability by Triggered Degradation 374
11.2.2 Dissociative Covalent Adaptive Networks 374
11.2.3 Vitrimers (Associative CANs) 376
11.3 Examples of Vitrimers 380
11.4 Adaptable Cross-Linking of Conventional Polymers 383
11.5 Outlook and Summary 385
References 387
12 Managing Plastic Wastes 391
Jean-Paul Lange
12.1 Introduction 391
12.2 Plastic Waste 391
12.3 Mechanical Recycling 393
12.4 Dissolution/Precipitation 394
12.5 Chemical Recycling 395
12.5.1 Depolymerization of Condensation Polymers 396
12.5.2 Melt Pyrolysis of Polyolefins 397
12.5.3 Alternative Pyrolysis Processes 398
12.6 Energy Recovery - Recycle Fuels and Incineration 400
12.7 Waste Destruction - Biodegradation 401
12.8 Life Cycle Analyses 401
12.9 Need for Fresh Carbon Input 402
12.10 Conclusion and Outlook 403
References 404
13 Life Cycle Assessment of Bio-Based Plastics: Concepts, Findings, and Pitfalls 409
li Shen
13.1 Introduction and Chapter Learning Objectives 409
13.2 “Bioplastics” Is a Confusing Term 409
13.3 LCA in a Nutshell 412
13.3.1 Concept and a Brief History 412
13.3.2 Procedure, Jargons, and Sciences Behind 413
13.3.2.1 Goal and Scope Definition 414
13.3.2.2 Life Cycle Inventory Analysis (LCI) 414
13.3.2.3 Life Cycle Impact Assessment (LCIA) 415
13.3.2.4 Interpretation 416
13.4 LCA Case Studies of Seven Single-Use Plastic Items Made from Bio-Based Resources: Highlights and Lessons Learned 417
13.4.1 Background, Aim, and Scope of the BIO-SPRI Study 417
13.4.2 Key Findings 419
13.4.2.1 Biomass Feedstock Acquisition 421
13.4.2.2 Manufacturing Phase: From Biomass to Polymers, Materials, and End Products 426
13.4.2.3 Distribution to End User: Impacts from Transportation 427
13.4.2.4 End-of-Life (EoL) Post-consumer Waste Management Scenarios 427
13.4.3 Comparisons with Petrochemical Plastics 431
13.5 Lessons Learned from the Case Studies and Looking Forward to a Circular Bio-Based Economy 432
13.a General Structure of Classification and Characterization in LCIA, using the example of 16 Impact Categories Recommended by the EC EF (Environmental Footprint) Impact Assessment Methods 434
13.b Normalization and Weighting Factors Recommended by the EF (Environmental Footprint) Method [12, 19, 46], Latest Update: May 2020 436
References 436
14 How to Create “A New Plastics Economy”? Marketing Strategies and Hurdles - Finding Application Niches 441
Sil Nevejans and Stefaan De Wildeman
14.1 Introduction 441
14.2 Stories from the Past 442
14.2.1 Polyhydroxyalkanoates (PHAs) 442
14.2.2 Polylactic Acids (PLA) 443
14.2.3 Polyethylenefuranoates (PEF) 444
14.3 Greenwashing vs. Growing Pains 444
14.4 From Idea to Product: “Technical Readiness Levels” 445
14.4.1 Defining the Technical Readiness Levels 445
14.4.2 Application of the TRLs 447
14.4.3 Product(ion) Validation 449
14.5 Five Innovation Rules to Create “A New Plastics Economy” 449
14.5.1 Target Small-Volume, High-Value Applications to Open New Market Space 450
14.5.2 Time Right Instead of Fast 451
14.5.3 Go Local 452
14.5.4 Take Risks 453
14.5.5 Go “Green” 454
14.6 Conclusion 455
References 456
Index 457
