Frontiers in the Science and Technology of Polymer Recycling NATO ASI Series Advanced Science Institute Series A Series presenting the results of activities sponsored by the NATO Science Committee, which aims at the dissemination of advanced scientific and technological knowledge, with a view to strengthening links between scientific communities. The Series is published by an international board of publishers in conjunction with the NATO Scientific Affairs Division A Life Sciences Plenum Publishing Corporation B Physics London and New York C Mathematical and Physical Sciences K1uwer Academic Publishers D Behavioural and Social Sciences Dordrecht, Boston and London E Applied Sciences F Computer and Systems Sciences Springer-Verlag G Ecological Sciences Berlin, Heidelberg, New York, London, H Cell Biology Paris and Tokyo I Global Environment Change PARTNERSHIP SUB-SERIES 1. Disarmament Technologies K1uwer Academic Publishers 2. Environment Springer-Verlag / K1uwer Academic Publishers 3. High Technology Kluwer Academic Publishers 4. Science and Technology Policy Kluwer Academic Publishers 5. Computer Networking Kluwer Academic Publishers The Partnership Sub-Series incorporates activities undertaken in collaboration with NATO's Cooperation Partners, the countries of the CIS and Central and Eastern Europe, in Priority Areas of concern to those countries. NATo-PCo-DATA BASE The electronic index to the NATO ASI Series provides full bibliographical references (with keywords and/or abstracts) to about 50,000 contributions from international scientists published in all sections of the NATO ASI Series. Access to the NATO-PCO-DATA BASE is possible via a CD-ROM "NATO Science and Technology Disk" with user-friendly retrieval software in English, French, and German (©wrv GmbH and DATAWARE Technologies, Inc. 1989). The CD-ROM contains the AGARD Aerospace Data- base. The CD-ROM can be ordered through any member of the Board of Publishers or through NATO-PCO, Overijse, Belgium. Series E: Applied Sciences - Vol. 351 Frontiers in the Science and Technology of Polymer Recycling edited by Guneri Akovali Middle East Technical University, Ankara, Turkey Carlos A. Bernardo University of Minho, Guimares, Portugal Jacob Leidner Ortec Corp., Missisagua, Ontario, Canada Leszek A. Utracki National Research Council of Canada, Boucherville, Quebec, Canada and Marino Xanthos Polymer Processing Institute at Stevens Institute of Technology, Hoboken, U.S.A. Springer-Science+Business Media, B.v. Proceedings of the NATO Advanced Study Institute on Frontiers in the Science and Technology of Polymer Recycling Antalya, Turkey 16 -27 June 1997 A C.I.P. Catalogue record for this book is available from the Library of Congress. ISBN 978-90-481-5074-8 ISBN 978-94-017-1626-0 (eBook) DOI 10.1007/978-94-017-1626-0 Printed on acid-free paper All Rights Reserved © 1998 Springer Science+Business Media Oordrecht Originally published by Kluwer Academic Publishers in 1998 No part of the material protected by this copyright notice may be reproduced or utilized in any form or by any means, electronic or mechanical, including photo- copying, recording or by any information storage and retrieval system, without written permission from the copyright owner. TABLE OF CONTENTS PREFACE IX LIST OF PARTICIPANTS Xlli GROUP PICTURE xxii CHAPTER 1. INTRODUCTION Introduction to Recycling J. Leidner 3 Regulations and Practices of Polymer Recycling in NATO Countries (A). European Countries D. Curto and Y. Ba~ar 17 Regulations and Practices of Polymer Recycling in NATO Countries (B). Canada and United States of America F. H. C. Edgecombe 29 Economic Aspects of Plastics Recycling M. J. Bevis 41 Polymer Recycling for Energy Recovery An Application of Life Cycle Analysis Principles M. Xanthos and A. L. Bisio 57 CHAPTER 2. FUNDAMENTAL ISSUES PERTINENT TO POLYMER RECYCLING Upgrading of Recyclates - the Solution for High Value Applications: Restabilization and Repair H. Herbst, K. Hoffmann, R. Pfaendner and H. Zweifel 73 VI Biodegradable Materials: State of Art and Future Perspectives C. Bastioli 103 Polymer Blends' Technology for Plastics Recycling L. A. Utracki 123 Compatibilization of Heterogeneous Polymer Mixtures from the Plastics Waste Streams H. J. Radusch, J. Ding and G. Akovali 153 Morphology Development During Processing of Recycled Polymers H. J. Radusch 191 CHAPTER 3. REPROCESSING OF SINGLE TYPE POLYMERS Derivation and Validation of Models to Predict the Properties of Mixtures of Virgin and Recycled Polymers C. A. Bernardo 215 Reprocessing of Poly (Vinyl chloride), Polycarbonate and Polyethyleneterepthalate F. P. La Mantia 249 Reprocessing of Polyolefins: Changes in Rheology and Reprocessing Case Studies A. T. P. Zahavich and J. Vlachopoulos 271 CHAPTER 4. REPROCESSING OF MIXTURE OF POLYMERS Separation Technologies J. Leidner and G. Boden 301 Reprocessing of Commingled Polymers and Recycling of Polymer Blends L. A. Utracki 333 Non-Convential Processing Techniques for Polymer Recycling M. J.Bevis 355 vii Reprocessing and Properties of Homopolymer Blends of Virgin and Recycled Polymers F. P. La Mantia 371 CHAPTER 5. RECOVERY OF CHEMICALS AND ENERGY PVC Recycling with Chlorine Recovery G.Menges 389 Thermolytic Processes M. Xanthos and J. Leidner 407 Solvolysis M. Xanthos and S. H. Patel 425 Fluidized Bed Incinerator with Energy Recovery System as a Means of Plastic Recycling S. Suzuki and T. Minoura 437 CHAPTER 6. THE WAY FORWARD Future Perspectives and Strategies of Polymer Recycling H. J. Radusch 451 General Discussion - the Participants' view 469 INDEX 473 PREFACE The main source of energy on earth is the Sun. From the energy and the basic raw materials we make products necessary for the daily life. Then, after a service span, the used-up products are discarded, usually returning to earth as waste. This has been going on for thousands of years. Through out the centuries that has passed, raw-materials were considered as boundless and their availability was only restricted by the capacity to collect and transform them. So was also considered the capacity of the earth to absorb and transform the waste. With time this has changed. On the one hand, world population kept growing and, on the other, the materials became more sophisticated. Not only the volume of the waste started to cumulate exponentially, but also its character has changed. The nature had to assimilate not only the classical materials like wood, but progressively different ones, with extended life-span, viz. ceramics, glasses, synthetics and advanced alloys. In the beginning of the 19th century there was a dramatic change in the availability of structural materials. First the rubber industry, then (about half a century later) the plastic industry was born. There was nothing in the history of humanity resembling the rapid expansion of the plastics technology. By the year 1900, global annual production of plastics was 30,000 tons, whereas 100 years later it will reach 151 million tons. Furthermore, in analogy to metallic alloys, polymers are progressively formulated to be more performing and less prone to the natural degradation processes, for example, during the last 25 years the UV stability of polypropylene fibers increased by a factor of II! Evidently, ancient methods of disposal by relying on the forces of nature are incapable to cope with the volume and quality of modem wastes. Only during the last two decades, the conscience of the natural limits, and the perception of the waste disposal problems become wide spread. We see ourselves interacting with the earth, a part of a cycle of materials and energy, and worry about the optimum way of managing it. The concept of recycling and recovery emerged mainly from this worry. So did ultimately this book. The twentieth century has been known as the century of plastics. On the volume basis, the plastics production is about three times as large as that of steel. In the industrialized countries, the annual consumption of plastics varies from 50 to 200 kg per person. It is amazing that this prominence was reached in less than two generations. IX x The notoriety of plastics is enhanced by their dominant role in disposable items, e.g., in packaging. Light in weight, high in rigidity and transparency, inexpensive plastic packaging is designed to be discarded after a single use. For many people this is unreasonable waste of high quality materials that clearly contributes to the growing problem of the global waste disposal. Few realize that the plastics content in the municipal waste amounts to 4-6 %. Plastics are visible, long lasting pollutants, that float on rivers, lakes and oceans. They are considered the eye-sore of the environment, or the so-called "visual pollution." To blame plastics for pollution is equivalent to blaming trees for the forest fires. However, in spite of the poor logic, the vision of plastics as being the main culprit for pollution, permeates the legislative bodies that impose targets for plastics recycling. Environmentalists have given the highest priority to reuse and recycle as means to handle plastics, or any other material, after their projected service time. However, these activities are only a part of the broader concept of recovery, that includes mechanical and chemical feedstock recycling as well as energy recuperation. Thus, recycling includes the concept that burning plastics can be used to save natural resources. Recycling also includes reprocessing of the waste generated by the plastics industry directly in-plant. Many fields of expertise are necessary for the understanding of problems involved in the value recovery from plastics waste, either as materials, chemicals or energy. For these reasons contributions are required from chemists, physicists, engineers as well as polymer and materials scientists. Due to the dimension of the subject, the participation of the environmental, legal and economic experts is also of paramount importance. It was therefore opportune for the workers in the forefront of these different areas to meet, to discuss and to exchange ideas. This, indeed, was achieved in the NATO Advanced Study Institute held at Antalya, Turkey, from June 16 to 27,1997. The lectures and discussions held during the Institute covered the totality of problems associated with plastics recycling. Regulations and practices of recycling in NATO countries, economics and energy criteria for assessing recycling provided the necessary framework for the discussion of these themes. Various educational, legal and economic aspects of the waste collection, as well as availability of raw materials for the recycling plants were considered in depth. While one of the principal emphasis was on the mechanical recycling (reprocessing) of plastics, other options, viz. thermolysis, solvolysis and energy recovery; have also been discussed in depth. Within the scope of the mechanical recycling, three basic areas were discussed: (I) the fundamentals of recycling, (2) the technology of recycling, and (3) the pertinent aspects of recycling specific polymers or their mixtures. Thus, basic properties of polymers found most Xl commonly in the waste stream were identified. The mechanical recycling can be performed using either a single-type of decontaminated resin, a clean mixture of polymers, or their contaminated varieties. For these reasons, diverse aspects of waste separation, segregation and cleaning were hotly debated. Fundamental and applied aspects of blends, their compatibilization and methods of suitable morphology development were presented. This constituted a basis for understanding the processing and performance of parts made from plastics waste. Since the materials were already exposed to melt processing and weathering, their stabilization is also of a paramount importance. One of the alternative of recycling is the use of polymers that can be easily decomposed by natural processes, namely by UV - and bio-degradation. The biodegradability of polymers is gaining acceptance in several domains of modern life, viz. compo sting bags, agricultural mulching films, loose-filler (to replace EPS), etc. The present world market is about 12 kton/y. Thus, the aspects of weatherability of polymers and their biodegradability were also discussed. Most of the lectures and discussions are presented in this volume. It is hoped that the book meets the ambitious goals of the Institute, and will become a reference for those interested in helping the society to attain sustainable development with plastics. The meeting was made possible by the supports of Nato Scientific Commitee and Advanced Study Institute and we want to acknowledge the kind cooperation provided to us at all times. Finally we want to thank to Prof. N. Uyanik (Istanbul Technical University), Miss T. Demir and Mr. S. Gokcesular (both from Middle East Technical University, Ankara) for their invaluable helps during the preparation and duration of the meeting. G. Akovali C. A. Bernardo J. Leidner L. A. Utracki M. Xanthos