Biodegradable polymers are niche market materials finding focused applications, including agricultural applications such as mulch films, flowerpots and controlled-release fertilisers and packaging items such as carrier bags and food wrapping and containers.

They have the potential to provide a solution to a range of environmental concerns: decreasing availability of landfill space, declining petrochemical sources, and also offer an alternative option to recycling.

Rapras Handbook of Biodegradable Polymers is a complete guide to the subject of biodegradable polymers and is ideal for those new to the subject or those wanting to supplement their existing knowledge.

The book covers the mechanisms of degradation in various environments, by both biological and non-biological means, and the methods for measuring biodegradation. The degree and rate of biodegradation is dependent on the chemical composition of the polymer and its working environment, and so there is no single optimal method for determining biodegradation. This handbook provides discussion of international and national standards and certification procedures developed to ensure accurate communication of a materials biodegradability between producers, authorities and consumers.

The book goes on to consider the characteristics, processability and application areas for biodegradable polymers, with key polymer family groups discussed.

About the editor...
Catia Bastioli is the Managing Director and Research Manager of Novamont, a leading innovation company in the sector of bioplastics. She is the author of more than 90 papers on various scientific and industrial subjects published in International Journals, Proceedings of International Conferences and books. She has filed more than 50 patents and patent applications in the sectors of synthetic and natural polymers. The patents in the sector of starch-based materials are a significant part of the Novamont patent portfolio.

 

TABLE OF CONTENTS

1 Biodegradability of Polymers - Mechanisms and Evaluation Methods

1.1 Introduction

1.2 Background

1.3 Defining Biodegradability

1.4 Mechanisms of Polymer Degradation

1.4.1 Non-biological Degradation of Polymers

1.4.2 Biological Degradation of Polymers

1.5 Measuring Biodegradation of Polymers

1.5.1 Enzyme Assays

1.5.2 Plate Tests

1.5.3 Respiration Tests

1.5.4 Gas (CO2 or CH4) Evolution Tests

1.5.5 Radioactively Labelled Polymers

1.5.6 Laboratory-scale Simulated Accelerating Environments

1.5.7 Natural Environments - Field Trials

1.6 Factors Affecting Biodegradability

1.7 Conclusions

2 Biodegradation Behaviour of Polymers in Liquid Environments

2.1 Introduction

2.2 Degradation in Real Liquid Environments

2.2.1 Degradation in Sweet Water and Marine Environment

2.3 Degradation in Laboratory Tests Simulating Real Aquatic Environments

2.3.1 Aerobic Liquid Environments

2.3.2 Anaerobic Liquid Environments

2.4 Degradation in Laboratory Tests with Optimised and Defined Liquid Media

2.5 Standard Tests for Biodegradable Polymers Using Liquid Media

2.6 Summary

3 Biodegradation Behaviour of Polymers in the Soil

3.1 I Introduction

3.1.1 Biodegradable Polymers and the Environment

3.1.2 Biodegradable Polymers and Soil

3.2 How Polymers Reach Soil

3.2.1 Intentional Delivery

3.2.2 Unintentional Delivery: Littering

3.3 The Soil Environment

3.3.1 Surface Factors

3.3.2 Underground Factors

3.4 Degradability of Polymers in Soil

3.4.1 The Standardisation Approach

3.4.2 T Test Methods and Criteria

3.5 Effects of Biodegradable Polymers on Soil Living Organisms

3.5.1 Performing the Assessment: Transient and Permanent Effects

3.5.2 Test Material Concentration

3.5.3 Preparation of the Soil Sample Ready for Ecotoxicity Testing

3.5.4 Test Methods

3.6 Biodegradability of Materials in Soil: A Survey of the Literature

4 Ecotoxicological Aspects in the Biodegradation Process of Polymers

4.1 The Need of Ecotoxicity Analysis for Biodegradable Materials

4.1.1 Standards and Regulations for Testing of Biodegradable Polymers

4.1.2 Detection of the Influences on an Ecosystem Caused by the Biodegradation of Polymers

4.1.3 Potential Influences of Polymers After Composting

4.1.4 Potential Influences of Polymers During and After Biodegradation in Soil and Sediment

4.2 A Short Introduction to Ecotoxicology

4.2.1 Theory of Dose-Response Relationships

4.2.2 Test Design in Ecotoxicology

4.2.3 Toxicity Tests and Bioassays

4.2.4 Ecotoxicity Profile Analysis

4.3 Recommendations and Standard Procedures for Biotests

4.3.1 Bioassays with Higher Plants

4.3.2 Bioassays with Earthworms (Eisenia foetida)

4.3 Preparation of Elutriates for Aquatic Ecotoxicity Tests

4.3.4 Bioassays with Algae

4.3.5 Bioassays with Luminescent Bacteria

4.3.6 Bioassays with Daphnia

4.3.7 Evaluation of Bioassay Results Obtained from Samples of Complex Composition

4.3.8 Testing of Sediments

4.4 Special Prerequisites to be Considered when Applying Bioassays for Biodegradable Polymers

4.4.1 Nutrients in the Sample

4.4.2 Biodegradation Intermediates

4.4.3 Diversity of the Microorganism Population

4.4.4 Humic Substances

4.4.5 Evaluation of Test Results and Limits of Bioassays

4.5 Research Results for Ecotoxicity Testing of Biodegradable Polymers

4.5.1 The Relationship Between Chemical Structure, Biodegradation Pathways and Formation of Potentially Ecotoxic Metabolites

4.5.2 Ecotoxicity of the Polymers

4.5.3 Ecotoxic Effects Appearing After Degradation in Compost or After Anaerobic Digestion

4.5.4 Ecotoxic Effects Appearing During Degradation in Soil

4.6 Conclusion

4.6.1 Consequences for Test Schemes for Investigations on Biodegradable Polymers

4.6.2 Conclusion

5 International and National Norms on Biodegradability and Certification Procedures

5.1 Introduction

5.2 Organisations for Standardisation

5.3 Norms

5.3.1 Aquatic, Aerobic Biodegradation Tests

5.3.2 Compost Biodegradation Tests

5.3.3 Compostability Norms

5.3.4 Compost Disintegration Tests

5.3.5 Soil Biodegradation Tests

5.3.6 Aquatic, Anaerobic Biodegradation Tests

5.3.7 High-Solids, Anaerobic Biodegradation Tests

5.3.8 Marine Biodegradation Tests

5.3.9 Other Biodegradation Tests

5.4 Certification

5.4.1 Introduction

5.4.2 Different Certification Systems

6 General Characteristics, Processability, Industrial Applications and Market Evolution of Biodegradable Polymers

6.1 General Characteristics

6.1.1 Polymer Biodegradation Mechanisms

6.1.2 Polymer Molecular Size, Structure and Chemical Composition

6.1.3 Biodegradable Polymer Classes

6.1.4 Naturally Biodegradable Polymers

6.1.5 Synthetic Biodegradable Polymers

6.1.6 Modified Naturally Biodegradable Polymers

6.2 Processability

6.2.1 Extrusion

6.2.2 Film Blowing and Casting

6.2.3 Moulding

6.2.4 Fibre Spinning

6.3 Industrial Applications

6.3.1 Loose-Fill Packaging

6.3.2 Compost Bags

6.3.3 Other Applications

6.4 Market Evolution

7 Polyhydroxyalkanoates

7.1 Introduction

7.2 The Various Types of PHA

7.2.1 Poly[R-3-hydroxybutyrate] (P[3HB])

7.2.2 Poly[3-hydroxybutyrate-co-3-hydroxyvalerate] (P[3HB-co-3HV])

7.2.3 Poly[3-hydroxybutyrate-co-4-hydroxybutyrate] (P[3HB-co-4HB])

7.2.4 Other PHA Copolymers with Interesting Physical Properties

7.2.5 Uncommon PHA Constituents

7.3 Mechanisms of PHA Biosynthesis

7.3.1 Conditions that Promote the Biosynthesis and Accumulation of PHA in Microorganisms

7.3.2 Carbon Sources for the Production of PHA

7.3.3 Biochemical Pathways Involved in the Metabolism of PHA

7.3.4 The Key Enzyme of PHA Biosynthesis, PHA Synthase

7.4 Genetically Modified Systems and Other Methods for the Production of PHA

7.4.1 Recombinant Escherichia coli

7.4.2 Transgenic Plants

7.4.3 In vitro Production of PHA

7.5 Biodegradation of PHA

7.6 Applications of PHA

7.7 Conclusions and Outlook

8 Starch-Based Technology

8.1 Introduction

8.2 Starch Polymer

8.3 Starch-filled Plastics

8.4 Thermoplastic Starch

8.5 Starch-Based Materials on the Market

8.6 Conclusions

9 Poly(Lactic Acid) and Copolyesters

9.1 Introduction

9.2 Synthesis

9.2.1 Homopolymers

9.2.2 Copolymers

9.2.3 Functionalised Polymers

9.3 Structure, Properties, Degradation, and Applications

9.3.1 Physical Properties

9.3.2 Chemical Properties

9.3.3 Applications

9.4 Conclusions

10 Aliphatic-Aromatic Polyesters

10.1 Introduction

10.2 Development of Biodegradable Aliphatic-Aromatic Copolyesters

10.3 Degradability and Degradation Mechanism

10.3.1 General Mechanism/Definition

10.3.2 Degradation of Pure Aromatic Polyesters

10.3.3 Degradation of Aliphatic-Aromatic Copolyesters

10.4 Commercial Products and Characteristic Material Data

10.4.1 Ecoflex

10.4.2 Eastar Bio

10.4.3 Biomax

10.4.4 EnPol

10.4.5 Characteristic Material Data

11 Material Formed from Proteins

11.1 Introduction

11.2 Structure of Material Proteins

11.3 Protein-Based Materials

11.4 Formation of Protein-Based Materials

11.4.1 'Solvent Process'

11.4.2 'Thermoplastic Process'

11.5 Properties of Protein-Based Materials

11.6 Applications

12 Enzyme Catalysis in the Synthesis of Biodegradable Polymers

12.1 Introduction

12.2 Polyester Synthesis

12.2.1 Polycondensation of Hydroxyacids and Esters

12.2.2 Polymerisation of Dicarboxylic Acids or Their Activated Derivatives with Glycols

12.2.3 Ring Opening Polymerisation of Carbonates and Other Cyclic Monomers

12.2.4 Ring Opening Polymerisation and Copolymerisation of Lactones

12.3 Oxidative Polymerisation of Phenol and Derivatives of Phenol

12.4 Enzymatic Polymerisation of Polysaccharides

12.5 Conclusions

13 Environmental Life Cycle Comparisons of Biodegradable Plastics

13.1 Introduction

13.2 Methodology of LCA

13.3 Presentation of Comparative Data

13.3.1 Starch Polymers

13.3.2 Polyhydroxyalkanoates

13.3.3 Polylactides (PLA)

13.3.4 Other Biodegradable Polymers

13.4 Summarising Comparison

13.5 Discussion

13.6 Conclusions

Appendix 13.1 Overview of environmental life cycle comparisons or biodegradable polymers included in this review

Appendix 13.2 Checklist for the preparation of an LCA for biodegradable plastics

Appendix 13.3 List of abbreviations

14 Biodegradable Polymers and the Optimisation of Models for Source Separation and Composting of Municipal Solid Waste

14.1 Introduction

14.1.1 The Development of Composting and Schemes for Source Separation of Biowaste in Europe: A Matter of Quality

14.2 The Driving Forces for Composting in the EU

14.2.1 The Directive on the Landfill of Waste

14.2.2 The Proposed Directive on Biological Treatment of Biodegradable Waste

14.3 Source Separation of Organic Waste in Mediterranean Countries: An Overview

14.5 'Biowaste', 'VGF' and 'Food Waste': Relevance of a Definition on Performances of the Waste Management System

14.6 The Importance of Biobags

14.6.1 Features of 'Biobags': The Importance of Biodegradability and its Cost-Efficiency

14.7 Cost Assessment of Optimised Schemes

14.7.1 Tools to Optimise the Schemes and their Suitability in Different Situations

14.8 Conclusions

Abbreviations

Contributors

Index