TECHNOLOGICAL APPLICATIONS OF DISPERSIONS SURFACTANT SCIENCE SERIES CONSULTING EDITORS MARTIN J. SCHICK FREDERICK M. FOWKES Consultant (1915-1990) New York, New York 1. Nonionic Surfactants, edited by Martin J. Schick (see also Volumes 19 and 23) 2. Solvent Properties of Surfactant Solutions, editedbyKozo Shinoda (out of print) 3. Surfactant Biodegradation, by R. D. Swisher (see Volume 18) 4. Cationic Surfactants, edited by Eric Jungermann (see also Volumes 34 and 37) 5. Detergency: Theory and Test Methods (in three parts), edited by W. G. Cutler and R. C. Davis (see also Volume 20) 6. Emulsions and Emulsion Technology (in three parts), edited by Kenneth J. Lissant 7. Anionic Surfactants (in two parts), edited by Warner M. Linfield (out of print) 8. Anionic Surfactants: Chemical Analysis, edited by John Cross (out of print) 9. Stabilization of Colloidal Dispersions by Polymer Adsorption, by Tatsuo Sato and Richard Ruch 10. Anionic Surfactants: Biochemistry, Toxicology, Dermatology, edited by Christian Gloxhuber (see Volume 43) 11. Anionic Surfactants: Physical Chemistry of Surfactant Action, edited by E. H. Lucassen-Reynders (out of print) 12. Amphoteric Surfactants, edited by B. R. Bluestein and Clifford L. Hilton (out of print) 13. Demulsification: Industrial Applications, by Kenneth J. Lissant 14. Surfactants in Textile Processing, by Arved Datyner 15. Electrical Phenomena at Interfaces: Fundamentals, Measurements, and Applications, edited by Ayao Kitahara and Akira Watanabe 16. Surfactants in Cosmetics, edited by Martin M. Rieger 17. Interfacial Phenomena: Equilibrium and Dynamic Effects, by Clarence A. Miller and P. Neogi 18. Surfactant Biodegradation, Second Edition, Revised and Expanded, by R. D. Swisher 19. Nonionic Surfactants: Chemical Analysis, edited by John Cross 20. Detergency: Theory and Technology, edited by W. Gale Cutler and Erik Kissa 21. Interfacial Phenomena in Apolar Media, edited by Hans-Friedrich Eicke and Geoffrey D. Parfitt 22. Surfactant Solutions: New Methods of Investigation, edited by Raoul Zana 23. Nonionic Surfactants: Physical Chemistry, edited by Martin J. Schick 24. Microemulsion Systems, edited by Henri L. Rosano and Marc Clausse 25. Biosurfactants and Biotechnology, edited by Nairn Kosaric, W. L. Cairns, and Neil C. C. Gray 26. Surfactants in Emerging Technologies, edited by Milton J. Rosen 27. Reagents in Mineral Technology, edited by P. Somasundaran and Brij M. Moudgil 28. Surfactants in Chemical/Process Engineering, edited by Darsh T. Wasan, Martin E. Ginn, and Dinesh O. Shah 29. Thin Liquid Films, edited by I. B. Ivanov 30. Microemulsions and Related Systems: Formulation, Solvency, and Physical Properties, edited by Maurice Bourrel and Robert S. Schecter 31. Crystallization and Polymorphism of Fats and Fatty Acids, edited by Nissim Garti and Kiyotaka Sato 32. Interfacial Phenomena in Coal Technology, edited by Gregory D. Botsaris and Yuli M. Glazman 33. Surfactant-Based Separation Processes, edited by John F. Scamehorn and Jeffrey H. Harwell 34. Cationic Surfactants: Organic Chemistry, edited by James M. Richmond 35. Alkylene Oxides and Their Polymers, by F. E. Bailey, Jr., and Joseph V. Koleske 36. Interfacial Phenomena in Petroleum Recovery, edited by Norman R. Morrow 37. Cationic Surfactants: Physical Chemistry, edited by Donn N. Rubingh and Paul M. Holland 38. Kinetics and Catalysis in Microheterogeneous Systems, edited by M. Gratzel and K. Kalyanasundaram 39. Interfacial Phenomena in Biological Systems, edited by Max Bender 40. Analysis of Surfactants, by Thomas M. Schmitt 41. Light Scattering by Liquid Surfaces and Complementary Techniques, edited by Dominique Langevin 42. Polymeric Surfactants, by Irja Piirma 43. Anionic Surfactants: Biochemistry, Toxicology, Dermatology. Second Edition, Revised and Expanded, edited by Christian Gloxhuber and Klaus Kunst/er 44. Organized Solutions: Surfactants in Science and Technology, edited by Stig E. Friberg and Bjorn Lindman 45. Defoaming: Theory and Industrial Applications, edited by P. R. Garrett 46. Mixed Surfactant Systems, edited by Keizo Ogino and Masahiko Abe 47. Coagulation and Flocculation: Theory and Applications, edited by Bohuslav DobiaS 48. Biosurfactants: Production • Properties • Applications, edited by Nairn Kosaric 49. Wettability, edited by John C. Berg 50. Fluorinated Surfactants: Synthesis • Properties • Applications, Erik Kissa 51. Surface and Colloid Chemistry in Advanced Ceramics Processing, edited by Robert J. Pugh and Lennart Bergstrom 52. Technological Applications of Dispersions, edited by Robert B. McKay 53. Cationic Surfactants: Analytical and Biological Evaluation, edited by John Cross and Edward J. Singer ADDITIONAL VOLUMES IN PREPARATION TECHNOLOGICAL APPLICATIONS OF DISPERSIONS edited by Robert B. McKay Ciba Pigments Paisley, Scotland Marcel Dekker, Inc. New York*Basel*Hong Kong Library of Congress Cataloging-in-Publication Data Technological applications of dispersions / edited by Robert B. McKay. p. cm. ~ (Surfactant science series; v. 52) Includes bibliographical references (p. - ) and index. ISBN 0-8247-9180-0 (acid-free) 1. Emulsions. 2. Suspensions (Chemistry) I. McKay, Robert B. II. Series. TP156.E6I53 1994 660'.2945»dc20 93-50099 CIP The publisher offers discounts on this book when ordered in bulk quantities. For more information, write to Special Sales/Professional Marketing at the address below. This book is printed on acid-free paper. Copyright © 1994 by Marcel Dekker, Inc. All Rights Reserved. Neither this book nor any part may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, microfilming, and recording, or by any information storage and retrieval system, without permission in writing from the publisher. Marcel Dekker, Inc. 270 Madison Avenue, New York, New York 10016 Current printing (last digit): 10 9 8 7 6 5 4 3 21 PRINTED IN THE UNITED STATES OF AMERICA Preface Dispersion science is of fundamental importance to a wide variety of tech- nologies. Indeed there are few chemically based technologies in which it does not feature in some role. This book aims to substantiate these state- ments by giving insight into a range of well established technologies of diverse character and in which dispersed particles play a key role. It is intended to provide a technological background for later books in the Sur- factant Science Series on specific aspects of dispersion science. The term dispersion in its broadest sense describes any system in which at least one phase is distributed in finely divided form throughout a contin- uous second phase. However, the technologies discussed in this book place emphasis on dispersions of solid particles in liquid or solid media. Emul- sions have been discussed in previous volumes of this series. The chapters are overviews of specific technologies written by technical experts. They illustrate the effects of dispersions in application and the means necessary for optimal achievement of these effects. The book should be of interest to formulators and users of dispersions, suppliers of compo- nents, industrial and academic scientists, and students of colloid science. The major application areas exemplified are surface coating, optical effects, uses of polymer dispersions, strength enhancement of inorganic materials, recording and display of information, and biological systems. Some of the major components of dispersions, especially pigments, are also discussed. Two major applications, namely ceramics (hence aspects of clays, and related materials) and agricultural chemicals, are the subjects of separate books in the series (in preparation), and so are mentioned only briefly here. The chapter on polymer dispersions for special purposes wid- iii iv Preface ens the scope of the book to include specific aspects of various other impor- tant applications, some of which could have become chapters in their own right. Clays have been discussed briefly in the chapter on paper coatings. The extensive literature quoted by the authors provides a further source of information. Some of the technologies included are interrelated. For example, the technologies of paints, printing inks, plastics, and man-made fibers are in part dependent upon pigment technology, and vice versa, and through this have much in common. There have been few texts that deal with such interrelated technologies collectively, and one aim of the book is to fill such gaps. The disperse phase has a specific function in all the applications, through factors such as chemical constitution, solid state and liquid-crystalline properties, physical structure, particle size, surface character. In some cases it does not survive as such in end use and in others it is transformed. The continuous phase may be solid or liquid, and in the latter case may be transformed by cooling, loss of solvent, or polymerization into a solid matrix or binder for the disperse phase. Interfacialproperties are of course critically important to the effectiveness of dispersions, through their influ- ences on dispersibility, dispersion stability, rheology, particle interactions, and interactions with substrates. It was difficult to decide the order of chapters. Paints were chosen as the subject of the first chapter because they are probably the earliest man-made dispersions and the most ubiquitous today. Then follow chapters on other technologies that entail or relate to dispersion of powders in liquids. The latter part of the book deals with more complex dispersions —first, those where changes are induced within the disperse phase by external influences during application and, second, those for probably the most complex appli- cation of all, biological systems. Some points of terminology require comment. The terms aggregate and agglomerate commonly used in dispersion technology present difficulty. IUPAC recommends that aggregate be used as a general term to describe any structure formed by the cohesion of colloidal particles [I]. Agglomerate is often used in colloid science and technology to describe small, strongly coherent aggregates. In pigment and pigment user industries, for example, the terms are used in an almost converse way — aggregate describing a strongly coherent cluster of colloidal particles and agglomerate a more loosely coherent assembly of particles, usually in a powder. In this book aggregate has been used in the general sense recommended by IUPAC, with some indication of strength of cohesion of constituent particles where appropriate. The term agglomerate has been avoided. Traditional terminology of some technologies is at odds with more gener- Preface v ally accepted terminology in dispersion science. For example, photographic emulsions and emulsion paints are really dispersions of solid particles, as indeed are many so-called polymer emulsions. In paper coating the terms pigment and color are applied to clay and calcium carbonate, even though, strictly speaking, such solids are colorless and have little direct opacifica- tion effect. I should like to thank Ciba Pigments for their encouragement and support. Robert B. McKay REFERENCE D. H. Everett (for IUPAC), Pure and Applied Chemistry, 57:579 (1972).