Biodegradable Polymers in the Circular Plastics Economy

Description

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. Cover Half Title Biodegradable Polymers in the Circular Plastics Economy Copyright Contents Preface 1. Biodegradable Polymers – A Tutorial for a Circular Plastics Economy 1.1 Context 1.2 Plastics in the Environment – Biodegradation and Impact of Litter 1.3 Biodegradable Polymers 1.3.1 Polyesters 1.3.2 Polysaccharides 1.3.3 Lignin 1.3.4 Vitrimers – Recyclable Thermosets 1.4 Beyond Biodegradation 1.4.1 Recycling and End‐of‐Life 1.4.2 LCA 1.4.3 Implementing the “New Plastics Economy” 1.5 Conclusions and Outlook References 2. Fundamentals of Polymer Biodegradation Mechanisms 2.1 Introduction 2.2 Overall Scheme of Polymer Degradation 2.3 Biodegradation of Polysaccharides 2.3.1 Cellulose 2.3.2 Starch 2.4 Biodegradation of Polyamides 2.5 Biodegradation of Polyesters 2.5.1 Polylactic Acid 2.5.2 Poly(ϵ‐caprolactone) 2.5.3 Polyhydroxyalkanoates 2.5.4 Polyethylene Terephthalate 2.6 Biodegradation of Hydrocarbons 2.6.1 Polyethylene 2.6.2 Polypropylene 2.6.3 Polystyrene 2.7 Biodegradation of Halogenated Polymers 2.7.1 Polyvinyl Chloride 2.7.2 Polytetrafluoroethylene 2.8 Biodegradation of Polyethers 2.8.1 Polyethylene Glycol 2.8.2 Polyurethane 2.9 Application of Biodegradation 2.10 Current Challenges and Future Prospects for Biodegradation of Plastics Wastes References 3. Plastic Pollution. The Role of (Bio)Degradable Plastics and Other Solutions 3.1 Introduction and Problem Definition 3.2 Sources of Macroplastics and MNPs 3.2.1 Mismanagement of Waste 3.2.2 Accidental Release 3.2.3 MNPs in Products 3.2.4 Degradation of Outdoor Objects 3.2.5 Wear (Tires, Clothing) 3.2.6 Waste and Wastewater Management (Water/Wind) 3.3 Impacts of Macroplastics and MNPs 3.3.1 Ecological Impact of Macroplastics (Entanglement and Ingestion) 3.3.2 Economic Impact of Macroplastics 3.3.3 Ecological Impacts of MNPs 3.3.3.1 Aquatic Environment 3.3.3.2 Terrestrial Environment 3.3.3.3 Atmosphere 3.3.4 Threat to Human Health 3.3.4.1 MNPs in the Human Food Chain 3.3.4.2 Plastic‐Related Contaminants 3.3.4.3 Other Contaminants 3.3.5 Socio‐Economic Impacts of MNPs 3.4 Plastic Biodegradability 3.5 Solutions 3.5.1 Cleaning Up 3.5.2 Waste Mitigation 3.5.3 Material Design 3.5.4 Bringing It All Together 3.5.5 Policies and Legislation 3.6 Conclusions References 4. Tutorial on Polymers – Manufacture, Properties, and Applications 4.1 Introduction 4.1.1 Today's Petrochemical Industry 4.1.2 Today's Bio‐based Plastic Industry 4.1.3 Environmental and Climate Challenges 4.2 Production of Polymers 4.2.1 Addition Polymers 4.2.2 Condensation Polymers 4.2.3 Thermosets 4.2.4 Renewable Monomers 4.2.4.1 Oils‐Based Monomers 4.2.4.2 Sugar‐Based Monomers 4.2.4.3 Lignocellulose‐Based Monomers 4.2.4.4 CO2‐Based Monomers 4.3 Main Polymers Applications 4.3.1 Rigids 4.3.2 Films 4.3.3 Fibers 4.3.4 Foams 4.3.5 CASE (Coatings, Adhesives, Sealants, Elastomers) 4.3.6 Composites 4.4 End‐of‐Life and Biodegradation 4.4.1 Reuse and Recycling 4.4.2 Biodegradation 4.5 Conclusions References 5. Condensation Polyesters 5.1 Introduction 5.2 Preparative Methods 5.3 Biodegradation of Polyesters 5.3.1 Hydrolytic Degradation 5.3.2 Enzymatic Degradation 5.4 Aliphatic Polyesters 5.4.1 Poly(alkylene dicarboxylates) 5.4.2 Poly(hydroxy acids) 5.4.3 Cyclic Sugar‐Based Monomers 5.5 Semi‐aromatic Polyesters 5.5.1 Poly(butylene adipate terephthalate) (PBAT) 5.5.2 Furanoate Copolymers 5.6 Cross‐linked Polyesters 5.6.1 Multifunctional Alcohols or Carboxylic Acids 5.6.2 Incorporation of Functional Monomers 5.6.3 Cross‐linking of Native Polyesters 5.7 Applications for Biodegradable Condensation Polyesters 5.7.1 Biomedical Applications 5.7.2 Agricultural Applications 5.7.3 Packaging Material 5.8 Polyester Recycling 5.9 Concluding Remarks References 6. Polyhydroxyalkanoates (PHAs) – Production, Properties, and Biodegradation 6.1 Introduction 6.1.1 General Aspects of Biodegradation of Polymers 6.1.2 General Aspects of Microbial Synthesis of PHAs 6.1.3 Types and Properties of PHAs 6.2 Biosynthesis – Substrates and Strains 6.2.1 Principle Stoichiometry of PHA Biosynthesis 6.2.2 Biosynthesis of scl‐ and mcl‐PHAs 6.2.3 Heterotrophic Feedstocks 6.2.4 Autotrophic Feedstocks 6.2.5 Syngas 6.2.6 Methane 6.2.7 Production Strains 6.3 Bioengineering: Bioreactor Design and Feeding Regime 6.3.1 Feeding Regime 6.3.2 Continuously Operated Bioreactors for Liquid Feed 6.3.3 Bioreactors for Gas Feed 6.3.4 Photo‐reactors for CO2 Feed 6.4 Downstream Processing for PHA Recovery 6.4.1 Classical Solvents 6.4.2 Halogen‐Free Solvents 6.4.3 Supercritical Solvents 6.4.4 Recovery by Chemical and Mechanical Disintegration of Biomass 6.4.5 Biological PHA Recovery 6.5 End‐of‐Life Options: Recycling and Biodegradation of PHAs 6.5.1 Recycling 6.5.2 Incineration 6.5.3 Mechanistic Considerations of PHA Degradation 6.6 Biodegradation – Added Value for Selected Applications 6.6.1 Packaging 6.6.2 Hygiene/Care/Cosmetics 6.6.3 Medical – Drug Delivery 6.6.4 Other Applications 6.7 Conclusions References 7. Ring‐Opening Polymerization Strategies for Degradable Polyesters 7.1 Introduction 7.2 Ring‐Opening Polymerization Mechanisms 7.2.1 Cationic Ring‐Opening Polymerization 7.2.2 Anionic Ring‐Opening Polymerization 7.2.3 Coordination–Insertion Ring‐Opening Polymerization 7.2.4 Enzymatic Ring‐Opening Polymerization 7.3 ROP‐Based Polyesters 7.3.1 Lactones 7.3.2 Thermodynamics and Kinetics 7.3.3 Functionalization 7.3.3.1 ROP of Functional Lactones 7.3.3.2 Post‐polymerization Functionalization 7.3.3.3 Grafting 7.3.4 Four‐Membered Lactones 7.3.4.1 β‐Butyrolactone 7.3.4.2 Acid‐Substituted β‐Lactones (β‐Malolactonate) 7.3.4.3 Alkoxy‐Substituted β‐Lactones 7.3.4.4 Alkene‐Substituted β‐Lactones 7.3.5 Five‐Membered Lactones 7.3.5.1 γ‐Butyrolactone 7.3.5.2 α‐Angelicalactone 7.3.5.3 α‐Methylene‐γ‐Butyrolactone 7.3.5.4 Ether γ‐Lactones 7.3.6 Six‐Membered Lactones 7.3.6.1 δ‐Valerolactone 7.3.6.2 Unsaturated δ‐Lactones 7.3.6.3 Ester‐Substituted δ‐Lactones 7.3.6.4 Ether δ‐Lactones 7.3.6.5 Dilactones 7.3.7 Seven‐Membered Lactones 7.3.7.1 ϵ‐Caprolactone 7.3.7.2 Substituted and Functionalized ϵ‐Caprolactone 7.3.7.3 Ether‐ϵ‐Lactones 7.4 Relations Between ROP Polymers and Degradability 7.5 Conclusion 7.6 Outlook and Recommendations References 8. Recent Developments in Biodegradable Cellulose‐Based Plastics 8.1 General Introduction 8.2 Cellulose 8.3 The Development of Cellulose Plastics 8.3.1 Cellulose Feedstock and Dissolving Pulp 8.3.2 Cellulose Derivatization 8.3.3 Cellulose Acetate and Cellulose Esters 8.3.4 Cellophane 8.3.5 Cellulose Fibers in Thermoplastic Formulations 8.4 Recent Developments in Thermoplastic Cellulose Derivatives 8.4.1 Characterization Methods for Lignocellulosic Biomass 8.4.2 Alternative Feedstocks for Dissolving Pulp and Production Routes 8.4.3 Ionic Liquids and Deep Eutectic Solvents for Cellulose Regeneration and Modification 8.4.4 New Derivatization Routes 8.4.5 Plasticizers 8.4.6 Mixed Cellulose Esters 8.4.7 Cellulose–Polymer Blends 8.4.8 (New) Properties and Processing Routes 8.4.9 New Applications 8.5 Biodegradation of Cellulose Derivatives 8.6 Conclusions References 9. Ester Derivatives of Microbial Synthetic Polysaccharides 9.1 Introduction 9.1.1 Background of Bio‐Based Plastics 9.1.2 Polysaccharides 9.2 Zero Birefringence Property of Pullulan Esters 9.3 Bio‐Based Adhesives from Dextran (α‐1,6‐Glucan) 9.4 Films and Fibers from Paramylon and Curdlan (β‐1,3‐Glucan) Esters 9.5 Polymerization of α‐1,3‐Glucan and Films of α‐1,3‐Glucan Esters 9.6 High‐Performance Polysaccharide‐Branched Esters 9.6.1 Cellulose‐Branched Esters 9.6.2 β‐1,3‐Glucan (Curdlan) Branched Esters 9.6.3 α‐1,3‐Glucan‐Branched Esters 9.7 Enzymatic Esterification of Polysaccharides 9.7.1 Enzymes as Biocatalysts 9.7.2 Reaction Mechanism 9.7.3 Factors Influencing Enzyme Activity 9.7.4 Strategies for Efficient Biocatalyst Processes 9.7.5 Development Trend and Prospects 9.8 Biodegradation of Polysaccharide Ester 9.9 Summary References 10. Biodegradable Lignin‐Based Plastics 10.1 Lignocellulose Biorefineries 10.2 Macromolecular Lignin Configuration 10.3 Industrial Availability of Lignins 10.4 Compelling Traits in Physicochemical Behavior of Kraft Lignin Species 10.5 Kraft Lignin‐Based Plastics 10.6 Tuning Strength and Production Cost of Plastics with High Kraft Lignin Contents 10.7 Ligninsulfonates (Lignosulfonates) 10.8 Laboratory Ball‐Milled Lignins 10.9 Blend Configuration in Ball‐Milled Lignin‐Based Plastics Exemplifies the General Case 10.10 Lignin–Lignin Blends 10.11 Biodegradation of Kraft Lignin‐Based Plastics 10.12 Alternative Formulations for Polymeric Materials Containing More than 50 wt% Lignin 10.13 Concluding Remarks Acknowledgments References 11. Design of Recyclable Thermosets 11.1 Introduction 11.1.1 Polymers and Plastics 11.1.2 Handling of Plastic Waste 11.1.3 Chemical Nature of Plastics 11.2 Design of Recyclable Thermosetting Polymers 11.2.1 Recyclability by Triggered Degradation 11.2.2 Dissociative Covalent Adaptive Networks 11.2.3 Vitrimers (Associative CANs) 11.3 Examples of Vitrimers 11.4 Adaptable Cross‐Linking of Conventional Polymers 11.5 Outlook and Summary References 12. Managing Plastic Wastes 12.1 Introduction 12.2 Plastic Waste 12.3 Mechanical Recycling 12.4 Dissolution/Precipitation 12.5 Chemical Recycling 12.5.1 Depolymerization of Condensation Polymers 12.5.2 Melt Pyrolysis of Polyolefins 12.5.3 Alternative Pyrolysis Processes 12.6 Energy Recovery – Recycle Fuels and Incineration 12.7 Waste Destruction – Biodegradation 12.8 Life Cycle Analyses 12.9 Need for Fresh Carbon Input 12.10 Conclusion and Outlook References 13. Life Cycle Assessment of Bio‐Based Plastics: Concepts, Findings, and Pitfalls 13.1 Introduction and Chapter Learning Objectives 13.2 “Bioplastics” Is a Confusing Term 13.3 LCA in a Nutshell 13.3.1 Concept and a Brief History 13.3.2 Procedure, Jargons, and Sciences Behind 13.3.2.1 Goal and Scope Definition 13.3.2.2 Life Cycle Inventory Analysis (LCI) 13.3.2.3 Life Cycle Impact Assessment (LCIA) 13.3.2.4 Interpretation 13.4 LCA Case Studies of Seven Single‐Use Plastic Items Made from Bio‐Based Resources: Highlights and Lessons Learned 13.4.1 Background, Aim, and Scope of the BIO‐SPRI Study 13.4.2 Key Findings 13.4.2.1 Biomass Feedstock Acquisition 13.4.2.2 Manufacturing Phase: From Biomass to Polymers, Materials, and End Products 13.4.2.3 Distribution to End User: Impacts from Transportation 13.4.2.4 End‐of‐Life (EoL) Post‐consumer Waste Management Scenarios 13.4.3 Comparisons with Petrochemical Plastics 13.5 Lessons Learned from the Case Studies and Looking Forward to a Circular Bio‐Based Economy References 14. How to Create “A New Plastics Economy”? Marketing Strategies and Hurdles – Finding Application Niches 14.1 Introduction 14.2 Stories from the Past 14.2.1 Polyhydroxyalkanoates (PHAs) 14.2.2 Polylactic Acids (PLA) 14.2.3 Polyethylenefuranoates (PEF) 14.3 Greenwashing vs. Growing Pains 14.4 From Idea to Product: “Technical Readiness Levels” 14.4.1 Defining the Technical Readiness Levels 14.4.2 Application of the TRLs 14.4.3 Product(ion) Validation 14.5 Five Innovation Rules to Create “A New Plastics Economy” 14.5.1 Target Small‐Volume, High‐Value Applications to Open New Market Space 14.5.2 Time Right Instead of Fast 14.5.3 Go Local 14.5.4 Take Risks 14.5.5 Go “Green” 14.6 Conclusion References Index