Advances in radiation chemistry of polymers

IAEA-TECDOC-1420

Advances in radiation chemistry of polymers

Proceedings of a technical meeting held in Notre Dame, Indiana, USA 13?17 September 2003

November 2004

IAEA-TECDOC-1420

Advances in radiation chemistry of polymers

Proceedings of a technical meeting held in Notre Dame, Indiana, USA 13?17 September 2003

November 2004

The originating Section of this publication in the IAEA was: Industrial Applications and Chemistry Section International Atomic Energy Agency Wagramer Strasse 5 P.O. Box 100 A-1400 Vienna, Austria

ADVANCES IN RADIATION CHEMISTRY OF POLYMERS IAEA, VIENNA, 2004 IAEA-TECDOC-1420 ISBN 92?0?112504?6 ISSN 1011?4289

? IAEA, 2004 Printed by the IAEA in Austria

November 2004

FOREWORD

Chemical reactions can be initiated by radiation at any temperature, under any pressure and in any phase (gas, liquid or solid) without the use of catalysts. The irradiation of polymeric materials with ionizing radiation (gamma rays, X rays, accelerated electrons, ion beams) leads to the formation of very reactive intermediates. These intermediates can follow several reaction paths, which result in rearrangements and/or formation of new bonds. The ultimate effects of these reactions can be the formation of oxidized products, grafts, scission of main chains (degradation) or cross-linking. The degree of these transformations depends on the structure of the polymer and the conditions of treatment before, during and after irradiation. Good control of all of these processing factors facilitates the modification of polymers by radiation processing.

This property of radiation processing was used early on for polymer modification. Nowadays, the modification of polymers covers radiation cross-linking, radiation induced polymerization (graft polymerization and curing) and the degradation of polymers. Likewise, medical products to be sterilized by radiation are often made from polymeric materials, which must be resistant to the administered dose.

Polymers are the materials most often treated by radiation. Therefore in the recent past the IAEA has organized Cooordinated Research Projects (CRPs) in closely related areas, namely the stability and stabilization of polymers under irradiation, the radiation vulcanization of natural rubber latex, the modification of polymers for biomedical applications such as the radiation synthesis of membranes, hydrogels and adsorbents.

The CRP on The Stability and Stabilization of Polymers under Irradiation was organized from 1994 to 1997 (IAEA-TECDOC-1062). The participants began research into the production of polymers under preparation of blends, which should withstand irradiation through the course of their useful lifetimes. They concluded that much remains to be learned in terms of understanding degradation mechanisms and phenomena. The application of radiation for the preparation of polymers for biomedical applications was the subject of the CRP on Radiation Synthesis and Modification of Polymers for Biomedical Applications implemented from 1996 to 2000 (IAEA-TECDOC-1324).

The Technical Meeting on Emerging Applications of Radiation Processing for the 21st Century organized in Vienna in April 2003 reviewed the present status and developments in radiation technology and its applications and identified the main fields of research and development to be explored within the framework of the IAEA programmes (IAEATECDOC-1386). The topics of follow-up meetings will cover these issues in order to stimulate research and development in the most important and promising areas. The consultants meeting on Advances in Radiation Chemistry of Polymers held at the University of Notre Dame, USA in September 2003 was the first in this series. The new developments concerning polymer processing were reported and the status of the technology was reviewed during the meeting.

The IAEA wishes to thank all the participants for their valuable contributions. The IAEA officer responsible for this publication was A.G. Chmielewski of the Division of Physical and Chemical Sciences.

EDITORIAL NOTE

This publication has been prepared from the original material as submitted by the authors. The views expressed do not necessarily reflect those of the IAEA, the governments of the nominating Member States or the nominating organizations.

The use of particular designations of countries or territories does not imply any judgement by the publisher, the IAEA, as to the legal status of such countries or territories, of their authorities and institutions or of the delimitation of their boundaries.

The mention of names of specific companies or products (whether or not indicated as registered) does not imply any intention to infringe proprietary rights, nor should it be construed as an endorsement or recommendation on the part of the IAEA.

The authors are responsible for having obtained the necessary permission for the IAEA to reproduce, translate or use material from sources already protected by copyrights.

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