Stephan KabasciEditor

Bio-Based PlasticsMaterials and Applications

WILEY SERIES IN RENEWABLE RESOURCES

Bio-Based Plastics

Wiley Seriesin

Renewable Resources

Series EditorChristian V. Stevens – Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium

Titles in the SeriesWood Modification – Chemical, Thermal and Other ProcessesCallum A. S. Hill

Renewables – Based Technology – Sustainability AssessmentJo Dewulf & Herman Van Langenhove

Introduction to Chemicals from BiomassJames H. Clark & Fabien E.I. Deswarte

BiofuelsWim Soetaert & Erick Vandamme

Handbook of Natural ColorantsThomas Bechtold & Rita Mussak

Surfactants from Renewable ResourcesMikael Kjellin & Ingegard Johansson

Industrial Application of Natural Fibres – Structure, Properties and TechnicalApplicationsJorg Mussig

Thermochemical Processing of Biomass – Conversion into Fuels, Chemicals and PowerRobert C. Brown

Biorefinery Co-Products: Phytochemicals, Primary Metabolites and Value-AddedBiomass ProcessingChantal Bergeron, Danielle Julie Carrier and Shri Ramaswamy

Aqueous Pretreatment of Plant Biomass for Biological and Chemical Conversion toFuels and ChemicalsCharles E. Wyman

Forthcoming TitlesIntroduction to Wood and Natural Fiber CompositesDouglas Stokke, Qinglin Wu & Guangping Han

Cellulosic Energy Cropping SystemsDoug Karlen

Cellulose Nanocrystals: Properties, Production and ApplicationsWadood Hamad

Introduction to Chemicals from Biomass, 2nd editionJames Clark & Fabien Deswarte

Lignin and Lignans as Renewable Raw Materials: Chemistry, Technology and ApplicationsFrancisco Garcıa Calvo-Flores, Jose A. Dobado, Joaquın Isac Garcıa, Francisco J. Martin-Martinez

Bio-Based PlasticsMaterials and Applications

Editor

STEPHAN KABASCIFraunhofer-Institute for Environmental, Safety, and

Energy Technology UMSICHT, Germany

This edition first published 2014C© 2014 John Wiley & Sons, Ltd

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Library of Congress Cataloging-in-Publication Data

Bio-based plastics : materials and applications / editor Stephan Kabasci.pages cm

Includes index.ISBN 978-1-119-99400-8 (cloth)

1. Biopolymers. 2. Plastics. I. Kabasci, Stephan.TP248.65.P62B5184 2014668.4–dc23

2013026528

A catalogue record for this book is available from the British Library.

ISBN: 978-1-119-99400-8

Cover images C© Fraunhofer UMSICHT

Set in 10/12pt Times by Aptara Inc., New Delhi, India

1 2014

Contents

Series Preface xiii

Preface xv

List of Contributors xvii

1 Bio-Based Plastics – Introduction 1Stephan Kabasci1.1 Definition of Bio-Based Plastics 21.2 A Brief History of Bio-Based Plastics 31.3 Market for Bio-Based Plastics 51.4 Scope of the Book 6

2 Starch 9Catia Bastioli, Paolo Magistrali, and Sebastia Gestı Garcia2.1 Introduction 92.2 Starch 102.3 Starch-Filled Plastics 132.4 Structural Starch Modifications 14

2.4.1 Starch Gelatinization and Retrogradation 142.4.2 Starch Jet-Cooking 162.4.3 Starch Extrusion Cooking 162.4.4 Starch Destructurization in Absence of Synthetic Polymers 172.4.5 Starch Destructurization in Presence of Synthetic Polymers 192.4.6 Additional Information on Starch Complexation 23

2.5 Starch-Based Materials on the Market 272.6 Conclusions 28References 28

3 Cellulose and Cellulose Acetate 35Johannes Ganster and Hans-Peter Fink3.1 Introduction 353.2 Raw Materials 36

vi Contents

3.3 Structure 373.3.1 Cellulose 373.3.2 Cellulose Derivatives 40

3.4 Principles of Cellulose Technology 423.4.1 Regenerated Cellulose 433.4.2 Organic Cellulose Esters – Cellulose Acetate 46

3.5 Properties and Applications of Cellulose-Based Plastics 523.5.1 Fibres 533.5.2 Films 543.5.3 Moulded Articles 56

3.6 Some Recent Developments 573.6.1 Cellulose 573.6.2 Cellulose Acetate and Mixed Esters 58

3.7 Conclusion 59References 59

4 Materials Based on Chitin and Chitosan 63Marguerite Rinaudo4.1 Introduction 634.2 Preparation and Characterization of Chitin and Chitosan 64

4.2.1 Chitin: Characteristics and Characterization 644.2.2 Chitosan: Preparation and Characterization 66

4.3 Processing of Chitin to Materials and Applications 694.3.1 Processing of Chitin and Physical Properties of Materials 694.3.2 Applications of Chitin-Based Materials 70

4.4 Chitosan Processing to Materials and Applications 714.4.1 Processing of Chitosan 714.4.2 Application of Chitosan-Based Materials 74

4.5 Conclusion 77References 77

5 Lignin Matrix Composites from Natural Resources – ARBOFORM R© 89Helmut Nagele, Jurgen Pfitzer, Lars Ziegler, Emilia Regina Inone-Kauffmann,Wilhelm Eckl, and Norbert Eisenreich5.1 Introduction 895.2 Approaches for Plastics Completely Made from Natural Resources 905.3 Formulation of Lignin Matrix Composites (ARBOFORM) 92

5.3.1 Lignin 925.3.2 Basic Formulations and Processing of ARBOFORM 955.3.3 The Influence of the Fibre Content 97

5.4 Chemical Free Lignin from High Pressure Thermo-Hydrolysis (Aquasolv) 1005.4.1 Near Infrared Spectroscopy of Lignin Types 1005.4.2 Lignin Extraction by High-Pressure Hydrothermolysis (HPH) 1015.4.3 Thermoplastic Processing of Aquasolv Lignin 104

5.5 Functionalizing Lignin Matrix Composites 1055.5.1 Impact Strength 106

Contents vii

5.5.2 Flame Retardancy 1065.5.3 Electrical Conductivity with Nanoparticles 1065.5.4 Pyrolysis to Porous Carbonaceous Structures 108

5.6 Injection Moulding of Parts – Case Studies 1095.6.1 Loudspeaker Boxes 1105.6.2 Precision Parts 1105.6.3 Thin Walled and Decorative Gift Boxes and Toys 111

Acknowledgements 112References 112

6 Bioplastics from Lipids 117Stuart Coles6.1 Introduction 1176.2 Definition and Structure of Lipids 117

6.2.1 Fatty Acids 1176.2.2 Mono-, Di- and Tri-Substituted Glycerols 1186.2.3 Phospholipids 1186.2.4 Other Compounds 119

6.3 Sources and Biosynthesis of Lipids 1196.3.1 Sources of Lipids 1196.3.2 Biosynthesis of Lipids 1206.3.3 Composition of Triglycerides 120

6.4 Extraction of Plant Oils, Triglycerides and Their Associated Compounds 1206.4.1 Seed Cleaning and Preparation 1216.4.2 Seed Pressing 1216.4.3 Liquid Extraction 1216.4.4 Post Extraction Processing 122

6.5 Biopolymers from Plant Oils, Triglycerides and Their AssociatedCompounds 1226.5.1 Generic Triglycerides 1226.5.2 Common Manipulations of Triglycerides 1236.5.3 Soybean Oil-Based Bioplastics 1256.5.4 Castor Oil-Based Bioplastics 1266.5.5 Linseed Oil-Based Bioplastics 1276.5.6 Other Plant Oil-Based Bioplastics 1276.5.7 Biological Synthesis of Polymers 128

6.6 Applications 1286.6.1 Mimicking to Reduce R&D Risk 1286.6.2 Composites 1296.6.3 Coatings 1296.6.4 Packaging Materials 1306.6.5 Foams 1306.6.6 Biomedical Applications 1306.6.7 Other Applications 131

6.7 Conclusions 131References 131

viii Contents

7 Polyhydroxyalkanoates: Basics, Production and Applications of MicrobialBiopolyesters 137Martin Koller, Anna Salerno, and Gerhart Braunegg7.1 Microbial PHA Production, Metabolism, and Structure 137

7.1.1 Occurrence of PHAs 1377.1.2 In Vivo Characteristics and Biological Role of PHAs 1397.1.3 Structure and Composition of PHAs 1407.1.4 Metabolic Aspects 141

7.2 Available Raw Materials for PHA Production 1437.3 Recovery of PHA from Biomass 144

7.3.1 General Aspects of PHA Recovery 1447.3.2 Direct Extraction of PHA from Biomass 1467.3.3 Digestion of the non-PHA Cellular Material 1477.3.4 Disruption of Cells of Osmophilic Microbes in

Hypotonic Medium 1487.4 Different Types of PHA 149

7.4.1 Short Chain Length vs. Medium Chain Length PHAs 1497.4.2 Enzymatic Background: PHA Synthases 149

7.5 Global PHA Production 1517.6 Applications of PHAs 152

7.6.1 General 1527.6.2 Packaging and Commodity Items 1527.6.3 Medical Applications 1547.6.4 Application of the Monomeric Building Blocks 1557.6.5 Smart Materials 1567.6.6 Controlled Release of Active Agents 156

7.7 Economic Challenges in the Production of PHAs and Attempts toOvercome Them 1567.7.1 PHA Production as a Holistic Process 1567.7.2 Substrates as Economic Factor 1567.7.3 Downstream Processing 1577.7.4 Process Design 1577.7.5 Contemporary Attempts to Enhance PHA Production in Terms of

Economics and Product Quality 1587.8 Process Design 1607.9 Conclusion 162References 163

8 Poly(Lactic Acid) 171Hideto Tsuji8.1 Introduction 1718.2 Historical Outline 1738.3 Synthesis of Monomer 1748.4 Synthesis of Poly(Lactic Acid) 176

8.4.1 Homopolymers 1768.4.2 Linear Copolymers 176

8.5 Processing 178

Contents ix

8.6 Crystallization 1788.6.1 Crystal Structures 1788.6.2 Crystalline Morphology 1818.6.3 Crystallization Behaviour 182

8.7 Physical Properties 1828.7.1 Mechanical Properties 1828.7.2 Thermal Properties 1868.7.3 Permeability 1888.7.4 Surface Properties 1888.7.5 Electrical Properties 1898.7.6 Optical Properties 189

8.8 Hydrolytic Degradation 1918.8.1 Degradation Mechanism 1928.8.2 Effects of Surrounding Media 1958.8.3 Effects of Material Parameters 196

8.9 Thermal Degradation 2008.10 Biodegradation 2048.11 Photodegradation 2058.12 High-Performance Poly(Lactic Acid)-Based Materials 207

8.12.1 Nucleating or Crystallization-Accelerating Fillers 2078.12.2 Composites and Nanocomposites 2088.12.3 Fibre-Reinforced Plastics (FRPs) 2118.12.4 Stereocomplexation 212

8.13 Applications 2138.13.1 Alternatives to Petro-Based Polymers 2138.13.2 Biomedical 2148.13.3 Environmental Applications 216

8.14 Recycling 2178.15 Conclusions 219References 219

9 Other Polyesters from Biomass Derived Monomers 241Daan S. van Es, Frits van der Klis, Rutger J. I. Knoop, Karin Molenveld,Lolke Sijtsma, and Jacco van Haveren9.1 Introduction 2419.2 Isohexide Polyesters 242

9.2.1 Introduction 2429.2.2 Semi-Aromatic Homo-Polyesters 2449.2.3 Semi-Aromatic Co-Polyesters 2479.2.4 Aliphatic Polyesters 2489.2.5 Modified Isohexides 250

9.3 Furan-Based Polyesters 2519.3.1 Introduction 2519.3.2 2,5-Dihydroxymethylfuran (DHMF)-Based Polyesters 2539.3.3 5-Hydroxymethylfuroic Acid (HMFA) Based Polyesters 2549.3.4 Furan-2,5-Dicarboxylic Acid (FDCA) Based Polyesters 2549.3.5 Future Outlook 256

x Contents

9.4 Poly(Butylene Succinate) (PBS) and Its Copolymers 2579.4.1 Succinic Acid 2579.4.2 1,4-Butanediol (BDO) 2589.4.3 Poly(Butylene Succinate) (PBS) 2599.4.4 PBS Copolymers 2599.4.5 PBS Biodegradability 2609.4.6 PBS Processability 2609.4.7 PBS Blends 2609.4.8 PBS Markets and Applications 2609.4.9 Future Outlook 261

9.5 Bio-Based Terephthalates 2619.5.1 Introduction 2619.5.2 Bio-Based Diols: Ethylene Glycol, 1,3-Propanediol,

1,4-Butanediol 2629.5.3 Bio-Based Xylenes, Isophthalic and Terephthalic Acid 263

9.6 Conclusions 267References 267

10 Polyamides from Biomass Derived Monomers 275Benjamin Brehmer10.1 Introduction 275

10.1.1 What are Polyamides? 27510.1.2 What is the Polymer Pyramid? 27610.1.3 Where do Polyamides from Biomass Derived Monomers Fit? 277

10.2 Technical Performance of Polyamides 27710.2.1 How to Differentiate Performance 27710.2.2 Overview of Current Applications 27910.2.3 Typical Association of Biopolymers 280

10.3 Chemical Synthesis 28110.3.1 Castor Bean to Intermediates 28110.3.2 Undecenoic Acid Route 28310.3.3 Sebacic Acid Route 28310.3.4 Decamethylene Diamine Route 284

10.4 Monomer Feedstock Supply Chain 28410.4.1 Description of Supply Chain 28410.4.2 Pricing Situation 285

10.5 Producers 28710.6 Sustainability Aspects 287

10.6.1 Biosourcing 28710.6.2 Lifecycle Assessments 28810.6.3 Labelling and Certification 291

10.7 Improvement and Outlook 292References 293

11 Polyolefin-Based Plastics from Biomass-Derived Monomers 295R.J. Koopmans11.1 Introduction 295

Contents xi

11.2 Polyolefin-Based Plastics 29611.3 Biomass 29911.4 Chemicals from Biomass 30011.5 Chemicals from Biotechnology 30211.6 Plastics from Biomass 30311.7 Polyolefin Plastics from Biomass and Petrochemical Technology 303

11.7.1 One-Carbon Building Blocks 30411.7.2 Two-Carbon Building Blocks 30511.7.3 Three-Carbon Building Blocks 305

11.8 Polyolefin Plastics from Biomass and Biotechnology 30511.9 Bio-Polyethylene and Bio-Polypropylene 30611.10 Perspective and Outlook 307References 308

12 Future Trends for Recombinant Protein-Based Polymers: The Case Studyof Development and Application of Silk-Elastin-Like Polymers 311Margarida Casal, Antonio M. Cunha, and Raul Machado12.1 Introduction 31112.2 Production of Recombinant Protein-Based Polymers (rPBPs) 31212.3 The Silk-Elastin-Like Polymers (SELPs) 314

12.3.1 SELPs for Biomedical Applications: Hydrogels for LocalizedDelivery 317

12.3.2 Mechanical Properties of SELP Hydrogels 31912.3.3 Spun Fibres 32012.3.4 Solvent Cast Films 323

12.4 Final Considerations 324References 325

13 Renewable Raw Materials and Feedstock for Bioplastics 331Achim Raschka, Michael Carus, and Stephan Piotrowski13.1 Introduction 33113.2 First- and Second-Generation Crops: Advantages and Disadvantages 33113.3 The Amount of Land Needed to Grow Feedstock for Bio-Based Plastics 33313.4 Productivity and Availability of Arable Land 33613.5 Research on Feedstock Optimization 33813.6 Advanced Breeding Technologies and Green Biotechnology 33913.7 Some Facts about Food Prices and Recent Food Price Increases 34113.8 Is there Enough Land for Food, Animal Feed, Bioenergy and Industrial

Material Use, Including Bio-Based Plastics? 343References 345

14 The Promise of Bioplastics – Bio-Based and Biodegradable-CompostablePlastics 347Ramani Narayan14.1 Value Proposition for Bio-Based Plastics 34814.2 Exemplars of Zero or Reduced Material Carbon Footprint – Bio-PE,

Bio-PET and PLA 349

xii Contents

14.3 Process Carbon Footprint and LCA 35114.4 Determination of Bio-Based Carbon Content 35214.5 End-of-Life Options for Bioplastics – Biodegradability-Compostability 35314.6 Summary 356References 356

Index 359

Series Preface

Renewable resources and their modification are involved in a multitude of important processeswith a major influence on our everyday lives. Applications can be found in the energy sector,chemistry, pharmacy, the textile industry, paints and coatings, to name but a few fields.

The broad area of renewable resources connects several scientific disciplines (agriculture,biochemistry, chemistry, technology, environmental sciences, forestry . . . ), but it is very diffi-cult to take an expert view on their complicated interactions. The idea of creating a series ofscientific books focusing on specific topics concerning renewable resources is therefore veryopportune and can help to clarify some of the underlying connections in this field.

In a very fast-changing world, trends do not only occur in fashion and politics; hype andbuzzwords occur in science too. The use of renewable resources is more important nowadays;however, it is not hype. Lively discussions among scientists continue about how long we willbe able to use fossil fuels, opinions ranging from 50 years to 500 years, but they do agree thatthe reserve is limited and that it is essential to search not only for new energy carriers but alsofor new material sources.

In this respect, renewable resources are a crucial area in the search for alternatives to fossil-based raw materials and energy. In the field of energy supply, biomass and renewable-basedresources will be part of the solution alongside other alternatives such as solar energy, windenergy, hydraulic power, hydrogen technology and nuclear energy.

In the material sciences, the impact of renewable resources will probably be even bigger.Integral crop use and the use of waste streams in certain industries will grow in importance,leading to a more sustainable way of producing materials.

Although our society was much more based on renewable resources centuries ago (almostexclusively so), this disappeared in the Western world in the nineteenth century. Now it istime to focus again on this field of research. This should not mean a retour a la nature, but itdoes require a multidisciplinary effort at a highly technological level to perform research onnew opportunities, to develop new crops and products from renewable resources. This will beessential to guarantee a level of comfort for a growing number of people living on our planet.The challenge for coming generations of scientists is to develop more sustainable ways to createprosperity and to fight poverty and hunger in the world. A global approach is certainly favoured.

This challenge can only be met if scientists are attracted to this area and are recognized fortheir efforts in this interdisciplinary field. It is therefore also essential that consumers recognizethe fate of renewable resources in a number of products.

xiv Series Preface

Furthermore, scientists do need to communicate and discuss the relevance of their work sothat the use and modification of renewable resources does not follow the path of the geneticengineering concept in terms of consumer acceptance in Europe. In this respect, the series willcertainly help to increase the visibility of the importance of renewable resources.

Being convinced of the value of the renewables approach for the industrial world, as wellas for developing countries, I was delighted to collaborate on this series of books focusingon different aspects of renewable resources. I hope that readers will become aware of thecomplexity, interactions, interconnections, and challenges of this field and that they will helpcommunicate the importance of renewable resources.

I would like to thank the staff from Wiley’s Chichester office, especially David Hughes,Jenny Cossham and Lyn Roberts, in seeing the need for such a series of books on renewableresources, for initiating and supporting it and for helping to carry the project through to the end.

Last but not least I want to thank my family, especially my wife Hilde and children, Paulienand Pieter-Jan, for their patience and for giving me the time to work on the series when otheractivities seemed to be more inviting.

Christian V. StevensFaculty of Bioscience Engineering

Ghent University, BelgiumSeries Editor ‘Renewable Resources’

June 2005

Preface

The world is becoming increasingly aware of the fact that fossil raw materials are a finiteresource. Their use needs to be reduced considerably in order to achieve sustainable develop-ment, defined by the UN Brundtland Commission in 1987 as: ‘development that meets the needsof the present without compromising the ability of future generations to meet their own needs.’

In the chemical products sector, bio-based raw materials are the only renewable alternativeto replace fossil carbon sources. In some product categories, such as detergents, renewableresources already hold a large share of the used raw materials due to their superior suitabil-ity and functionality. In the major chemical product category (with respect to the annuallyproduced amount) of plastics, however, renewable resources still play a very small role.Nonetheless, steadily increasing numbers of bio-based polymers and products thereof havebeen developed. Moreover, the number of scientific papers for this topic is growing rapidly.

This book, as a part of the ‘Wiley Series on Renewable Resources’ presents a wide range ofbio-based plastics and highlights some of their applications. Emphasis is placed on materialsthat are presently in use or show a significant potential for future applications. The bookcontains an up-to-date, broad, but concise overview of basic and applied aspects of bioplastics.The main focus is on thermoplastic polymers for material use. Elastomers, thermosets andcoating applications, like natural rubber or alkyd resins, will be covered in other volumes inthe series.

The book is organized in several chapters and deals with the most important biopoly-mer classes like the different polysaccharides (starch, cellulose, chitin), lignin, proteins and(polyhydroxy alkanoates) as raw materials for bio-based plastics, as well as with materialsderived from bio-based monomers like lipids, poly(lactic acid), polyesters, polyamides andpolyolefines. Additional chapters on general topics – the market and availability of renewableraw materials, the importance of bio-based content and the aspect of biodegradability – provideimportant information related to all bio-based polymer classes.

On behalf of all the authors, I would like to invite you to enter the world of bio-basedplastics. Enjoy reading!

Stephan KabasciFraunhofer-Institute for Environmental, Safety,and Energy Technology UMSICHT, Germany

July 2013

List of Contributors

Catia Bastioli Chief Executive Officer, Novamont S.p.A., Italy

Gerhart Braunegg ARENA Arbeitsgemeinschaft fur Ressourcenschonende und Nach-haltige Technologien, Austria

Benjamin Brehmer Evonik Industries AG, Germany

Michael Carus nova-Institut GmbH, Germany

Margarida Casal CBMA (Centre of Molecular and Environmental Biology), Departmentof Biology, University of Minho, Portugal

Stuart Coles International Digital Laboratory, WMG, University of Warwick, UnitedKingdom

Antonio M. Cunha IPC (Institute of Polymers and Composites), Department of PolymerEngineering, University of Minho, Portugal

Wilhelm Eckl Fraunhofer Institute for Chemical Technology ICT, Germany

Norbert Eisenreich Fraunhofer Institute for Chemical Technology ICT, Germany

Daan S. van Es Wageningen University and Research Centre – Food and Biobased Research,Netherlands

Hans-Peter Fink Fraunhofer Institute for Applied Polymer Research IAP, Germany

Johannes Ganster Fraunhofer Institute for Applied Polymer Research IAP, Germany

Sebastia Gestı Garcia R&D-Physical Chemistry Laboratory, Novamont S.p.A., Italy

xviii List of Contributors

Emilia Regina Inone-Kauffmann Fraunhofer Institute for Chemical Technology ICT,Germany

Stephan Kabasci Fraunhofer Institute for Environmental, Safety, and Energy TechnologyUMSICHT, Germany

Frits van der Klis Wageningen University and Research Centre – Food and BiobasedResearch, Netherlands

Rutger J. I. Knoop Wageningen University and Research Centre – Food and BiobasedResearch, Netherlands

Martin Koller Graz University of Technology, Institute of Biotechnology and Biochem-ical Engineering, Austria and ARENA Arbeitsgemeinschaft fur Ressourcenschonende undNachhaltige Technologien, Austria

R.J. Koopmans Dow Europe GmbH, Switzerland

Raul Machado CBMA (Centre of Molecular and Environmental Biology), Department ofBiology, University of Minho, Portugal

Paolo Magistrali R&D-Physical Chemistry Laboratory, Novamont S.p.A., Italy

Karin Molenveld Wageningen University and Research Centre – Food and BiobasedResearch, Netherlands

Helmut Nagele Tecnaro GmbH, Germany

Ramani Narayan Department of Chemical Engineering and Materials Science, MichiganState University, United States

Jurgen Pfitzer Tecnaro GmbH, Germany

Stephan Piotrowski nova-Institut GmbH, Germany

Achim Raschka nova-Institut GmbH, Germany

Marguerite Rinaudo Biomaterials Applications, 6 rue Lesdiguires, France

Anna Salerno Graz University of Technology, Institute of Biotechnology and BiochemicalEngineering, Austria

Lolke Sijtsma Wageningen University and Research Centre – Food and Biobased Research,Netherlands

List of Contributors xix

Hideto Tsuji Department of Environmental and Life Sciences, Graduate School ofEngineering, Toyohashi University of Technology, Japan

Jacco van Haveren Wageningen University and Research Centre – Food and BiobasedResearch, Netherlands

Lars Ziegler Tecnaro GmbH, Germany

1

Bio-Based Plastics – Introduction

Stephan KabasciFraunhofer Institute for Environmental, Safety, and Energy Technology UMSICHT, Germany

The world is becoming increasingly aware of the fact that fossil raw materials are a finiteresource. Around the year 2010, circa 7 × 109 t of fossil carbon were being extracted fromoil, coal and natural gas reservoirs annually. This demand has led to a considerable increasein fossil raw material prices, threatening the world’s economy, and has been responsible forthe rise in atmospheric carbon dioxide concentration over the past two centuries, affecting theworld’s climate. The massive use of fossil materials also presents an ethical problem. It can beforeseen that within a few generations these resources will be depleted. Their use needs to bereduced considerably in order to reach a sustainable level of development, defined by the UNBrundtland Commission in 1987 as: ‘development that meets the needs of the present withoutcompromising the ability of future generations to meet their own needs’.

More than 90% of raw fossil material utilization is for the purpose of satisfying the world’senergy demand. A small fraction is converted to chemical products. Regarding the energysector, several alternative technologies have already been developed. Wind, water, solar andgeothermal sources can be used to set up a sustainable energy supply. Worldwide they alreadyconstitute, for example, 20% of electricity generation. Increasing the proportion of energy thatis produced from renewable sources is a social and political goal in a lot of countries.

In the chemical products sector bio-based raw materials are the only renewable alternativeto replace fossil carbon sources. In some chemical product categories like, for example,detergents, renewable resources already make up a large share of the raw materials used due totheir superior suitability and functionality. In the major chemical product category (with respectto the annually produced amount) of plastics, however, renewable resources still play a verysmall role. Nonetheless, steadily increasing numbers of bio-based polymers and products havebeen developed in recent years. The number of scientific papers on this topic is still growingrapidly while it remains at a constant level for traditional fossil-based polymeric materials.

Bio-Based Plastics: Materials and Applications, First Edition. Edited by Stephan Kabasci.© 2014 John Wiley & Sons, Ltd. Published 2014 by John Wiley & Sons, Ltd.

2 Bio-Based Plastics

This book covers a wide range of different bio-based plastics and highlights some of theirapplications.

1.1 Definition of Bio-Based Plastics

According to the Technical Report 15392, drawn up by the Technical Committee CEN/TC 249of the European Committee for Standardization (CEN) in August 2009, ‘bio-based plastics’are plastics derived from biomass. ‘Plastics’, as laid down in EN ISO 472, are materials thatcontain as an essential ingredient a high polymer and which at some stage in their processinginto finished products can be shaped by flow. ‘Biomass’ means nonfossilized and biodegradableorganic material originating from plants, animals and micro-organisms. Biomass is consideredas a renewable resource as long as its exploitation rate does not exceed its replenishment bynatural processes.

Although the above definition describes bio-based plastics rather unambiguously, someconfusion still can be noticed, mainly due to the use of the inaccurate term ‘bioplastics’. Theprefix ‘bio-’ in bioplastics sometimes is used not to indicate the origin of the material (‘bio-based’) but to express a ‘bio’-functionality of the material, in general either biodegradabilityor biocompatibility.

Biodegradable plastics can undergo decomposition processes induced by micro-organismsin composting or anaerobic digestion processes. Decomposition must proceed down to theultimate stage of small molecules like methane (CH4) and/or carbon dioxide (CO2), water(H2O) and mineral salts. Different national and international standards (e.g. ASTM D 6400,EN 13 432, ISO 17 088) have been developed, in which the process criteria (e.g. temperatureand time) of test procedures and methods to analyse ultimate decomposition are laid down.Only if materials tested according to one of the standards yield more than the required minimumdecomposition rate may they be designated as ‘biodegradable’ with reference to the testingmethod. The process of biodegradation is closely linked to the molecular structure of thepolymer, it does not depend on the origin of the material. Some fossil-based polymers, likepolycaprolactone (PCL), or poly(butylene adipate terephthalate) (PBAT), are biodegradableaccording to these standards. On the other hand, there are bio-based plastics, like polyethylene(PE), from sugar cane, which are resistant to biodegradation.

Biocompatible plastics are used in medicinal applications, and the prefix ‘bio’ indicatesthat the polymer, when being immersed in a living organism (human or animal), does notharm the body or its metabolism in any way. These biopolymers can also be based on fossilraw materials or on renewable resources. They may be durable in the body, as in the case ofartificial blood vessels, or they may disintegrate and be resorbed in the body, as in the case ofresorbable suture threads.

Another form of ambiguity arises from the definition of ‘biopolymers’ in biochemistry.These are polymers synthesized by living organisms (animals, plants, algae, micro-organisms)like polysaccharides, proteins, lignin or nucleic acids. They exhibit different functions in theorganisms like energy storage (starch, proteins, polyhydroxyalkanoates), structural materials(lignin, cellulose, chitin, proteins) metabolism (proteins – enzymes, nucleic acids) or infor-mation storage (nucleic acids). Direct industrial exploitation of native biopolymers is possibleafter extraction and purification, that is, by physical processes. Further industrial exploitationis possible by applying chemical functionalization processes to the natural polymers. Resultsof these physical or chemical processes can be bio-based plastics, like polyhydroxyalkanoates(PHA), or cellulose acetate (CA). On the other hand, bio-based plastics do not need to be

Bio-Based Plastics – Introduction 3

Bio-basedplastics

Based onNatural polymers

Lignin

Proteins

Monomers fromchemical synthesis

Isosorbide,furanics, etc.

Succinic acid,lactic acid, etc.

Cellulose,chitin, etc.

Starch

Cyanophycin,PHAs, etc.

Monomers frombiochemicalsynthesis

Natural rubber

Polysaccharides

Structural P.s.

Storage P.s.

Others

Polymerizedform bio-based

monomers

Figure 1.1 Overview of bio-based plastics.

derived from natural polymers. Poly(lactic acid), one of the most important bio-based plastics,is being produced by chemical polymerization of the bio-based monomer, lactic acid.

Figure 1.1 gives an overview of bio-based plastics. The distinction between materialsbased on natural polymers and those polymerized from bio-derived monomers can be seenfrom this.

Returning to the CEN definition of ‘bio-based plastics’ as plastics derived from biomass,while there is no difficulty in attesting a physically extracted natural biopolymer like poly-hydroxybutyrate (PHB) to be 100% bio-based, applying chemical modifications to naturalpolymers or using bio-based monomers together with petrochemical monomers in a poly-condensation reaction for example yields partially bio-based products. For example, 1,3-propanediol is being produced in the United States from corn starch using a biotechnologicalprocess. This monomer is 100% bio-based. By combining it with fossil-based terephthalicacid in a polycondensation reaction, a polyester, namely poly(propylene terephthalate) alsoknown as poly(trimethylene terephthalate) (PTT), is being produced. This polyester is partiallybio-based. International standardization on defining and measuring the bio-based fraction insuch a material still is underway. Looking, for example, at the bio-based carbon atom contentof PTT yields a bio-based fraction of 3/(3 + 8) = 27%. Nevertheless, different calculations,for example taking all chemical elements into account, are possible in principle.

1.2 A Brief History of Bio-Based Plastics

Looking at the historic development of plastics production, we can see that in the beginning itwas not driven by using fossil raw materials. Quite the contrary – a lot of thermosets, elastomers

4 Bio-Based Plastics

and some thermoplastics were originally developed on the basis of renewable resources. Thus,the history of bioplastics in its first stages stands for the history of polymeric materials ingeneral.

According to the German Plastics Museum, the first mention of a raw material for plasticsproduction in the year 1530 was casein, a milk protein. A Bavarian Benedictine abbey keepsthe recipe for producing artificial horn from casein. In the last decades of the eighteenth centuryand the first half of the nineteenth century, natural rubber was modified and used for differentapplications. This development ranges from the simple natural rubber eraser, described byPriestley in 1770, to Hancock’s masticator in 1819, Goodyear’s vulcanization process and T.Hancock’s hard rubber, which was intended as a substitute for ebony, both in 1841. Soon after,in the mid-1840s, linoleum based on linseed oil (Walton) and cellulose nitrate (Schonbein)were invented. In 1854, J.A. Cutting was the first to use camphor as a plasticizer for cellulosenitrate to produce films. After an intermediate development step from Parkes, who presentedthe compound ‘Parkesin’ in 1856, this material combination, cellulose nitrate and camphor,was optimized by J. W. Hyatt, who created the first thermoplastic material, ‘celluloid’, in 1868.His invention was initiated by a contest for the development of a substitute material for ivoryto produce billiard balls.

This bio-based plastic celluloid and its developer Hyatt gave rise to the plastics industry in theUnited States and worldwide. The production of celluloid billiard balls by the Albany BilliardBall Corporation started in 1869, and three years later Hyatt constructed the predecessorof an injection moulding machine to produce parts in various shapes from celluloid. Atthe end of the nineteenth century the protein casein once again came under the focus ofbioplastics development. In 1897 Krische and Spiteller invented Galalith, also known asErinoid, a thermoset material from formaldehyde-hardened casein that was mainly used forthe production of buttons and jewellery. In 1908, Eichengrun developed cellulose acetate, atransparent material with similar characteristics to cellulose nitrate, but with the huge advantageof being less flammable. Ten years later he also laid the foundation for the further rapiddevelopment of the plastics industry by inventing a manual piston injection moulding machineto process plasticized cellulose acetate. However, with crude oil becoming available at lowprices and based on the theoretic works of Staudinger, in the 1920s and 1930s, the majorityof fossil-based plastics types that are presently used (e.g. PE, PVC, PS, PA, PMMA) weredeveloped. In these same decades, two important bio-based plastics were investigated in detail.Polyhydroxyalkanoates, which are synthesized as energy storage materials by several micro-organisms, were isolated and described by Lemoigne in 1925. Poly(lactic acid) (PLA) had beensynthesized in 1913 and W.H. Carothers, one of the outstanding polymer chemists of that age,investigated the synthesis and the material in detail in 1932. Because of its biocompatibilityand the ability to be resorbed in the human body, PLA and co-polyesters of lactic acid andglycolic acid have been produced for medical applications since the 1950s. Another bio-based raw material, castor oil, was exploited from the 1940s, when undecenoic acid, oneof the pyrolytic degradation products of ricinoleic acid, was firstly used in the production ofpolyamide 11. After this, some decades of massive growth in production of fossil-based plasticsfollowed and materials like PE, PVC, PS, PMMA and later on PP have been dominating theplastics world.

In parallel to the upcoming environmental protection movements of the 1980s, the awarenessof the need for replacing fossil-based raw materials increased. The use of starch for theproduction of bioplastic materials was investigated and the first materials based on this research

Bio-Based Plastics – Introduction 5

entered the market in the 1990s. In that same decade, high-volume production of PLA fornonmedicinal use started and the first tests of biodegradable PHA packaging materials wereperformed. Ten years later, considerable production capacity for several types of bio-basedpolymers had built up. With the advent, in particular, of fully bio-based drop-in materials, likebio-polyethylene (Bio-PE), and partially bio-based drop-in materials, like bio-poly(ethyleneterephthalate) (Bio-PET with bio-derived ethylene glycol), production capacities of bioplasticssurpassed 1 million t in 2011.

1.3 Market for Bio-Based Plastics

Looking at the different types of plastics and their applications large differences in the shareof bio-based materials can be found. In 2010, the German Federal Agency for RenewableResources presented data for the German market in the year 2007, which was analysed inthree different sectors: thermoplastic and thermoset resins, elastomers, and man-made fibres(Figure 1.2).

The proportion of bio-based materials in each of the sectors of elastomers and fibresaccounted for almost 40% due to the use of 290 000 t of natural rubber and 300 000 tof cellulosic fibres. The market size for thermoplastics and thermosets amounted to circa15.8 million t, of which circa 12.5 million t accounted for rigid materials, mainly in packaging,building and construction, automotive and electronics industries as well as for furniture andconsumer goods. A volume of 3.3 million t is attributed to adhesives, paints and lacquers,binders and other polymeric additives. In these areas it is estimated that bio-based materials

Plastics /polymers

Man-madefibres

Thermoplastic andthermoset resins

Elastomers

36% bio-based(290 kt of ca. 800 kt)

38% bio-based(300 kt of ca. 800 kt)

<< 1% bio-based(45 kt of ca. 12.5 million t)

10% bio-based(340 kt of ca. 3.3 million t)

2% bio-based(385 kt of ca. 15.8 million t)

Rigid materials(packaging, building andconstruction, automative,

electronics, etc.)

Other applications(adhesives, paints and

laquers, binders, polymericadditives, etc.)

6% bio-based(975 kt of ca. 17.4 million t)

Figure 1.2 Share of bio-based plastics in the German market (as of 2007). (Data from the German FederalAgency for Renewable Resources.)

6 Bio-Based Plastics

hold a share of circa 10%, while in the sector of rigid materials the bio-based plastics marketsize of 45 000 t merely amounts to circa 0.4% of the total market size.

A lot of market studies focus on thermoplastic bio-based plastics as rigid materials, describ-ing the present status of these materials and predicting future growth rates. In this plasticsapplication segment, global annual production capacity of bio-based materials surpassed 1million t in 2011. Despite the low absolute value, bio-based plastics saw a rapid increase inproduction capacity, for example from 2003 (100 000 t) to 2007 (360 000 t), with a continuousaverage growth rate of 38% p.a.

For the near future this trend will continue. According to a study from the EuropeanBioplastics association and the University of Applied Sciences and Arts of Hannover, thisvalue will increase fivefold to an estimated 5.8 million t in 2016. The main driver of such anenormous expected rise is attributed to the 2011 decision of a leading worldwide soft drinkcompany to substitute all of their PET bottles by (at least) partly bio-based PET, in which theethylene glycol unit is derived from bioethanol – accounting for 4.6 million t. Thus, productioncapacity for bio-based drop-in commodity plastics (Bio-PET and Bio-PE) will largely overtakethat of biodegradable materials. Poly(lactic acid), for example, was the predominant bio-basedplastics material from 2000 to 2010, with annual production capacities of 100 000–150 000 tin this decade. This bio-based and biodegradable resin is predicted to undergo a twofoldproduction capacity increase up to circa 300 000 t in 2016, too. Despite this rise, its share ofthe overall bio-based plastics market will drop from circa 35% to merely 5%.

Looking generally at the broad range of bio-based plastic types, most studies agree upona growth of production capacities due to more and more companies entering and investing inthe market. In 2009, circa 20 companies held 90% of the bioplastics market. By 2015 morethan 250 and by 2020 over 2000 companies are expected to be at that market. Asia and SouthAmerica will most likely have the highest growth rates and investments in the next decade.

Caused by the foreseen increase in Bio-PET production until 2016, bottles together withother packaging applications will be the dominant usage sectors of bio-based plastics. Never-theless, progress in the development of processing and functional additives like, for example,flame retardants will also enhance the use of bio-based plastics in semi-durable and durableapplications like transportation, construction, electronics, furniture and consumer goods ingeneral. Key issues in all of these areas in general are material-, process-, and eco-efficiency.Common requirements for distinct materials in mass production are process efficiency, highperformance and price adequate performance. They can be met by intelligent design, cheapand reliable material choices, as well as by improvements in process design and develop-ment. These optimization steps together with rising prices for fossil raw materials can allowbio-based plastics to reach the limits of maximum technical substitution potential, which wascalculated to be 90% of the total consumption of plastics and fibres, based on the material mixof 2007.

1.4 Scope of the Book

This book focuses on bio-based plastics. It emphasizes materials that are presently in use or thatshow a significant potential for future applications. It presents a broad, up-to-date but conciseoverview of basic and applied aspects of bioplastics. The main focus is on thermoplasticpolymers for material use. Elastomers, thermosets and coating applications, like, for example,natural rubber or alkyd resins, will be covered in other volumes of the series.

Bio-Based Plastics – Introduction 7

The book addresses the most important biopolymer classes like polysaccharides, lignin,proteins and polyhydroxyalkanoates as raw materials for bio-based plastics, as well as materialsderived from bio-based monomers like lipids, poly(lactic acid), polyesters, polyamides andpolyolefines. Additional chapters on general topics – the market and availability of renewableraw materials, the importance of bio-based content and the issue of biodegradability – willprovide important information related to all bio-based polymer classes.