**Meet the editor**

Dimitris S. Achilias occupies the position of Associate Professor in Polymer Chemistry and Technology at the Department of Chemistry, Aristotle University of Thessaloniki, Greece. He obtained his diploma in Chemical Engineering in 1985 and his Ph.D. in 1991 from AUTh. He has published 105 papers in international refereed scientific journals and has received nearly 2800 citations

with h-index 29. He has presented almost 130 research works in conferences and written 7 chapters in international books. Dr. Achilias edited the book Materials Recycling, InTech, with 98000 all chapters downloads. He has supervised 47 graduate, 27 post-graduate and 5 doctorate theses. He has participated in a number of Greek and European research projects. Dr. Achilias research interests include the chemical recycling of polymers and modelling of polymerization kinetics.

## Contents

#### **Preface XI**


## Preface

The continuous improvement of the standards of living has lead to a dramatic increase in the produc‐ tion and consumption of materials. Since the life duration of a number of wastes is very small (roughly 40% have duration of life smaller than one month), there is a vast waste stream that reaches each year to the final recipients creating a serious environmental problem. Presently, most common practice of han‐ dling such waste streams is to incinerate them with energy recovery or to use them for land-filling. Dis‐ posing of the waste to landfill is becoming undesirable due to legislation pressures, rising costs and the poor biodegradability of commonly used materials. Reducing the amount of solid wastes in landfills is one of the main targets in nowadays wastes' treatment. Therefore, recycling seems to be the best solu‐ tion. The major driving force in today's recycling project is not only to re-use the materials but also to produce secondary value-added products, reducing the consumption of natural resources and the amount of energy needed, while lowering CO2 emissions in the environment. One additional goal in a globally successful recycling project is to use environmentally friendly procedures (such as those de‐ creasing energy consumption, or using naturally occurring materials) in order not to surcharge the envi‐ ronment. To this direction, there is a great need in finding of smart recycling techniques which should, as is possible, to be environmentally friendly.

As it is well-known, the word re-cycling comes from the Greek word 'κύκλος' meaning cycle and is usually used to denote the involvement of materials in a continuous cycle from 'cradle' (resources) to 'grave' (dis‐ posal of waste) and back to 'cradle' (re-formation of resources).

The intention of this book is to present some recent methods for the recycling of several materials, in‐ cluding plastics and wood, as well as to show the importance of composting of polymers. It targets pro‐ fessionals, recycling companies, researchers, academics and graduate students in the fields of waste management and polymer recycling in addition to chemical engineering, mechanical engineering, chemistry and physics.

This book comprises 5 chapters that have been prepared from the contribution of 7 co-authors from Japan, Greece, I.R. Iran and USA. In the first three chapters, different novel polymer recycling techni‐ ques are presented using environmentally friendly procedures, in the forth, the importance of compo‐ stable polymers and nanocomposites is discussed, whereas in the fifth, the potential for introduction of preservative treated wood in wood waste recycling streams is illustrated. A brief description of each chapter follows.

Chapter 1. Recycling of Expanded Polystyrene Using Natural Solvents

In this chapter, the selective dissolution of expanded polystyrene (EPS) is illustrated as a way of its recy‐ cling. Several naturally-occurring solvents, including terpenes and terpenoids are examined. The solu‐ bility of EPS in these solvents is presented together with the dissolving power of these monoterpenes. Certain criteria are set to define whether a specific terpene is suitable to be used as a solvent for PS recycling. PS is finally recovered using steam distillation. Thus, harmful organic solvents are omitted from the recycling procedure.

Chapter 2. Hydrothermal Depolymerization of Polyesters and Polycarbonate in the Presence of Ammo‐ nia and Amines

In this chapter, methods for the chemical recycling of poly(ethylene terephthalate) PET, poly(ethylene naphthalate) PEN and polycarbonate, PC using hydrothermal conversion of the polymers in aqueous ammonia and amine solutions are reviewed. This process is attractive due to highly selective conversion to monomers, easy separation of monomers in resultant aqueous solutions, and relatively mild reaction conditions, i.e., temperature lower than the melting point of polymer and low concentration of ammo‐ nia or amines.

Chapter 3. Chemical and Thermo-chemical Recycling of Polymers from Waste Electrical and Electronic Equipment

This chapter provides a critical review on the chemical and thermo-chemical methods proposed and/or applied, during mainly the last decade, on the recycling of polymers from waste electrical and electronic equipment (WEEE). Recycling methods such as the dissolution-reprecipitation and pyrolysis are pre‐ sented. Special emphasis is given in three different polymers, i.e. polycarbonate (PC), high impact poly‐ styrene (HIPS) and Acrylonitrile-Butadiene-Styrene (ABS) which are commonly found in WEEE. The state-of-the-art of the chemical and thermo-chemical recycling methods of these polymers is illustrated, emphasizing to environmentally friendly techniques, such the use of microwave irradiation instead of conventional heating.

Chapter 4. Compostable Polymers and Nanocomposites - A big chance for the Planet Earth.

In this chapter, the significance of composting composites and nanocomposites based on bio-based pol‐ ymers used in various applications to reduce the amount of solid waste in landfills is presented. Fur‐ thermore, composting methods to produce compostable materials and international standard test methods for evaluation of the above mentioned materials are illustrated.

Chapter 5. Potential for Introduction of Preservative Treated Wood in Wood Waste Recycling Streams and its Prevention

Recycling of woody debris promises to remove a substantial volume from the waste stream, thereby prolonging the useful life of the limited landfill capacity. One potential issue with these recycling pro‐ grams is the potential for contamination of the recycling stream with treated wood. Treated wood is supposed to be either reused in a similar application or, if that cannot be done, disposed of in a munici‐ pal solid waste facility. However, it can sometimes be difficult to distinguish treated wood from other materials and varying amounts of treated wood are entering the waste stream. This chapter outlines methods for assessing volumes of treated wood in the recycling stream, examines the potential risks of this material and then identifies possible methods for excluding these materials.

I want to express my sincere thanks to all the contributors who provided their expertise and enthusiasm to this project and InTech for making this work possible. I would like also to thank my wife Maria and the sons Savvas, Diamantis and Yiannis for their patience and the time deprived them during the prepa‐ ration of my chapter and the book editing. I dedicate this book to them.

> **Dimitris S. Achilias** Associate Professor Department of Chemistry Aristotle University of Thessaloniki Greece
