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Books > Science & Mathematics > Chemistry > Organic chemistry > Polymer chemistry
Natural products like wool, leather or cotton are permeable to water vapor. Their complex fibrous structure makes it difficult to imitate this natural phenomenon by synthesis. This book discusses ways to obtain water vapor permeability by microporosity or through a hydrophilic structure. Various areas of application include the medical sector for implants and dialysis, the industrial sector for filtration or for processes requiring the slow release of substances, and the consumer sector for leather substitutes or performance textiles.
In 1975, a symposium was held in Midland, Michigan, co-sponsored by the Dow Chemical Company and the then Midland Macromolecular Institute in honor of Raymond F. Boyer on the occasion of his 65th birthday and retirement from Dow. The topic of that first Boyer symposium dealt with an area of interest to Boyer, namely, polymer transitions and relaxations. One decade later, after ten years of additional fruitful scientific endeavor at MMI, Ray Boyer was again honored with a symposium, this time celebrating his 75th birthday and 10th anniversary at the Michigan Molecular Institute. The topic of the second Boyer symposium in 1985 was somewhat more focused, this time concentrating on the subject of order (or structure) in the amorphous state of polymers and the attendant polymer transitions that are observed. This volume contains the full manuscripts of the contributors to the 17th MMI International Symposium, held in Midland, Michigan on August 18-21, 1985. Eleven one-hour plenary lectures and ten 20-minute contributed papers were presented during the Symposium. An open forum panel discussion was also scheduled; the edited transcript of that session is included at the end of this volume. One of our tasks in organizing this Symposium was to attempt to gather together a number of speakers who would be able to define what, if any, physical structure might be present in anwrplwus polymers and what the nature of this order might be.
Until comparatively recently, trace analysis techniques were in general directed toward the determination of impurities in bulk materials. Methods were developed for very high relative sensitivity, and the values determined were average values. Sampling procedures were devised which eliminated the so-called sampling error. However, in the last decade or so, a number of developments have shown that, for many purposes, the distribution of defects within a material can confer important new properties on the material. Perhaps the most striking example of this is given by semiconductors; a whole new industry has emerged in barely twenty years based entirely on the controlled distribu tion of defects within what a few years before would have been regarded as a pure, homogeneous crystal. Other examples exist in biochemistry, metallurgy, polyiners and, of course, catalysis. In addition to this of the importance of distribution, there has also been a recognition growing awareness that physical defects are as important as chemical defects. (We are, of course, using the word defect to imply some dis continuity in the material, and not in any derogatory sense. ) This broadening of the field of interest led the Materials Advisory Board( I} to recommend a new definition for the discipline, "Materials Character ization," to encompass this wider concept of the determination of the structure and composition of materials. In characterizing a material, perhaps the most important special area of interest is the surface.
Everything flows, so rheology is a universal science. Even if we set aside claims of such width, there can be no doubt of its importance in polymers. It joins with chemistry in the polymerisation step but polymer engineering is supreme in all the succeeding steps. This is the area concerned with the fabrication of the polymer into articles or components, with their design to meet the needs in service, and with the long and short term performance of the article or component. This is a typical area of professional engineering activity, but one as yet without its proper complement of professional engineers. An understanding of polymer rheology is the key to effective design and material plus process selection, to efficient fabrication, and to satisfactory service, yet few engineers make adequate use of what is known and understood in polymer rheology. Its importance in the flow processes of fabrication is obvious. Less obvious, but equally important, are the rheological phenomena which determine the in-service performance. There is a gap between the polymer rheologist and the polymer engineer which is damaging to both parties and which contributes to a less than satisfactory use of polymers in our society. It is important that this gap be filled and this book makes an attempt to do so. It presents an outline of what is known in a concise and logical fashion. It does this starting from first principles and with the minimum use of complex mathematics.
'Recent Advances in Elastomeric Nanocomposites' reviews the recent progresses in the synthesis, processing as well as applications of elastomeric nanocomposites. Elastomers are a very important class of polymer materials and the generation of their nanocomposites by the incorporation of nano-filler has led to significant enhancement of their properties and, hence, expansion of their application potential. Most of the studies related with these materials are present in the form of research papers. Here, the authors present a comprehensive text covering the whole of the subject. The book is tailored more from the applications point of view, but also provide enough introductory material for research scholars new to this field.
The title of this volume implies a progression of sorts from species of molecular size to a product described on the basis of continuum prop erties. The difference in approach from the standpoint of molecular be havior, on the one hand-more the forte of chemists-and from the standpoint of large-scale properties, on the other-more the province of chemical engineers and materials scientists-represents a severe cultural divide, but one with much potential for creative input from both sides. Chapter 1 of this volume attempts a broad survey of trends toward the synthesis of large, well-defined molecular systems with interesting physical, chemical, or material properties. Review articles with more de tailed treatments are emphasized. In Chapter 2, Newkome and Moore field summarize work on synthesis of /I cascade" molecules. Next, Denti, Campagna, and Balzani describe the synthesis of assemblies with con nected metal-containing chromophore units which transmit electrons or electronic energy in defined ways. In Chapter 4 Wuest describes the con struction of hydrogen-bonded organic networks, and in Chapter 5 Michl defines a molecular-level construction set. Finally, Jaszczak points out how nature's attempts over geological time spans are emulated by recent human synthetic activity in the fullerene arena, through the appearance of various morphologies of natural graphite. The book concludes with a method for describing fractal-like mole cules, and an index based on the method for appropriate compounds described in the text."
This book is intended to provide a fundamental basis for the study of the interaction of polymers with living systems, biochemicals, and with aqueous solutions. The surface chemistry and physics of polymeric materials is a subject not normally covered to any significant extent in classical surface chemistry textbooks. Many of the assumptions of classical surface chemistry are invalid when applied to polymer surfaces. Surface properties of polymers are important in the development of medical devices and diagnostic products. Surface properties are also of vital importance in fields such as adhesion, paints and coatings, polymer-filler interactions, heterogeneous catalysis, composites, and polymers for energy generation. The book begins with a chapter considering the current sources of information on polymer surface chemistry and physics. It moves on to consider the question of the dynamics of polymer surfaces and the implica tions of polymer surface dynamics on all subsequent characterization and interfacial studies. Two chapters are directed toward the question of model polymers for preparing model surfaces and interfaces. Complete treatments of X-ray photoelectron spectroscopy and attenuated total reflection infrared spectroscopy are given. There is a detailed treatment of the contact angle with particular emphasis on contact angle hysteresis in aqueous systems, followed by chapters on interfacial electrochemistry and interface acid-base charge-transfer properties. The very difficult problem of block and graft copolymer surfaces is also discussed. The problem of theoretical calculations of surface and interfacial tensions is presented. Raman spectroscopy is considered as an analytical technique for polymer surface characterization."
This volume constitutes the Proceedings of the Sixth University Conference on Ceramic Science which was held at North Carolina State University in Raleigh, December 7-9, 1970. Previous host institutions and resultant publications in this ongoing series have been: 1. North Carolina State University, November 16-18, 1964. W. W. K:r>iegeZ and H. PaZmour III~ Eds. ~ The RoZe of Grain Boundaries and Surfaaes in Ceramias. 631 pp.~ Mater'iaZs Saienae Researah~ Vol-. 3~ PZenwn P1'eSs~ New York~ 1966 . * 2. University of Notre Dame, June 21-23, 1965. G. C. Kuazynski~ N. A. Hooten and C. F. Gibbon~ Eds.~ Sintering and ReZated Phenomena~ 894 pp. Gordon and Breaah Saienae PubZishers~ Ina.~ New York~ 1967. 3. University of California at Berkeley, June 13-16, 1966. R. M. FuZrath and J. A. Pask~ Eds.~ Ceramia ~arostruatures- Their AnaZysis~ Signifiaanae and Produatidn. 1008 pp. John WiZey & Sons~ Ina.~ New York~ 1968. 4. State University of New York, College of Ceramics at Alfred University, June 18-23, 1967. T. J. Gray and V. D. Freahette~ Eds.~ Kinetias of Reaations in Ionia SoZids. 571 pp. MateriaZs Saienae Researah~ VoZ. 4~ PZenwn Press~ New York~ 1969. 5. University of Florida, Novem1:>er 10-14, 1969. L. L. Henah and D. B. Dove~ Eds.~ Physias of EZeatronia Ceramias. M. Dekker~ Ina. (In Press).
Polymer science is a technology-driven science. More often than not, technological breakthroughs opened the gates to rapid fundamental and theoretical advances, dramatically broadening the understanding of experimental observations, and expanding the science itself. Some of the breakthroughs involved the creation of new materials. Among these one may enumerate the vulcanization of natural rubber, the derivatization of cellulose, the giant advances right before and during World War II in the preparation and characterization of synthetic elastomers and semi crystalline polymers such as polyesters and polyamides, the subsequent creation of aromatic high-temperature resistant amorphous and semi-crystal line polymers, and the more recent development of liquid-crystalline polymers mostly with n~in-chain mesogenicity. other breakthroughs involve the development of powerful characterization techniques. Among the recent ones, the photon correlation spectroscopy owes its success to the advent of laser technology, small angle neutron scattering evolved from n~clear reactors technology, and modern solid-state nuclear magnetic resonance spectroscopy exists because of advances in superconductivity. The growing need for high modulus, high-temperature resistant polymers is opening at present a new technology, that of more or less rigid networks. The use of such networks is rapidly growing in applications where they are used as such or where they serve as matrices for fibers or other load bearing elements. The rigid networks are largely aromatic. Many of them are prepared from multifunctional wholly or almost-wholly aromatic kernels, while others contain large amount of stiff difunctional residus leading to the presence of many main-chain "liquid-crystalline" segments in the "infinite" network.
The 27th Europhysics Conference on Macromolecular Physics focused on applications of scattering methods to the dynamics of polymer dense systems and covered Rayleigh-Brillouin scattering and photon correlation spectroscopy, quasi-elastic neutron scattering, holographic methods, real time X-ray and neutron scattering techniques as well as the treatment of theoretical models and computer simulations of polymer dynamics.
Simulation and molding are efficient techniques that can aid the city and regional planners and engineers in optimizing the operation of urban systems such as traffic light control, highway toll automation, consensus building, public safety, and environmental protection. When modeling transportation systems such as freeway systems, arterial or downtown grid systems, the city planner and engineer is concerned with capturing the varied interactions between drivers, automobiles, and the infrastructure. Modeling and simulation are used to effectively optimize the design and operation of all of these urban systems. It is possible that in an urban simulation community workshop, citizens can work interactively in front of computers and be able using the click of the mouse to walk up to their own front porch, looking at the proposed shopping mall alternatives across the street from virtually any angle and proposed bridge or tunnel and see how it can reduce traffic congestion. Buildings can be scaled down or taken out, their orientation can be changed in order to check the view and orientation in order to have better site with efficient energy-conservation. The stone or brick material on a building can be replaced by colored concrete, or more trees and lampposts can be placed on the site. Such flexibility in simulation and animation allows creative ideas in the design and orientation of urban sites to be demonstrated to citizens and decision makers before final realization.
This marks the first publieation of the Division of Polymer Chemistry, Ine., Ameriean Chemieal Soeiety, bien nia1 polymer symposia. This new series will feature new and novel deve10pments in polymer seience and technology as presented at these symposia. This volume reports the proeeeding of the Eighth Bi ennia1 Polymer Symposium of the Division of Polymer Chem istry held at Key Biseayne, Florida on November 20 - 24, 1976. It is eoneerned with a number of developments having both scientifie and praetical significance. These inelude polymerie liquid erysta1 systems in the melt and in solu tion, polymer blends, and nove1 polymers in extended chain conformations produced by solid-state polymerization. Rates of eonformationa1 transitions and cis-trans isomeri zations in polymers, a new look at rubber elasticity theory and new synthetie procedures for stiffening polymer ehains are some of the new scientific developments. The book conc1udes with two approaches for the use of polymers in the important field of slow drug release. The authors are all we1l-known seientists and inelude Nobel Laureate Paul Flory, first recipient of the Polymer Division Award whieh was presented at this Symposium. Eli M. Pearee John R. Schaefgen v CONTENTS The Molecular Theory of Rubber Elasticity 1 (Polymer Division Award Address) P. J. Flory Liquid Crystalline Solutions from POlyhydrazides in Aqueous Organic Bases . . . . . . . 19 J. D. Hartzler and P. W. Morgan Properties of Rigid-Chain Polymers in Dilute and Concentrated Solutions . . . ."
Triennial the Division of Biomedical Engineering of the Institute of Textile Technology and Chemical Engineering, Denkendorf, is organizing conferences on specific topics in the field of polymeric materials for use in the biomedical areas. The aim is to bring together scientists from allover the world working on this speci fic topic, to present the newest state of the art and to discuss their problems in a more concentrated atmosphere and at last to create and intensivate their cooperation. Following two conferences on "Polyurethanes in Biomedical Engi neering" (1983 and 1986), the Institute of Textile Technology and Chemical Engineering set a theme, which is very closely related to its own task: "Medical Textiles for Implantation". As technical materials, textiles can be classified in two fields of application: - first, textiles used for highly flexible, strong, but only tension load bearing systems, e.g. tows; - second, textiles manufactured to flat shaped devices to separate two regions more or less semipermeable, e.g. clothing; - a combination of both are reinforced systems like tubular fabrics e.g.; here pressure load will be transformed to tensile load, the separation may be performed by a coating. In the biological systems the classification can be used in the same manner: - Tension load bearing structures are ligaments and tendons, semipermeable separation is realized by cell membranes as well as by cell layers, for example the skin. - The combination of both of the principles can be found for example in arteries and the trachea.
To the surprise of practically no one, research and engineering on multi polymer materials has steadily increased through the 1960s and 1970s. More and more people are remarking that we are running out of new monomers to polymerize, and that the improved polymers of the future will depend heavily on synergistic combinations of existing materials. In the era of the mid-1960s, three distinct multipolymer combinations were recognized: polymer blends, grafts, and blocks. Although inter penetrating polymer networks, lPNs, were prepared very early in polymer history, and already named by Millar in 1960, they played a relatively low-key role in polymer research developments until the late 1960s and 1970s. I would prefer to consider the IPNs as a subdivision of the graft copolymers. Yet the unique topology of the IPNs imparts properties not easily obtainable without the presence of crosslinking. One of the objectives of this book is to point out the wealth of work done on IPNs or closely related materials. Since many papers and patents actually concerned with IPNs are not so designated, this literature is significantly larger than first imagined. It may also be that many authors will meet each other for the first time on these pages and realize that they are working on a common topology. The number of applications suggested in the patent literature is large and growing. Included are impact-resistant plastics, ion exchange resins, noise-damping materials, a type of thermoplastic elastomer, and many more."
The molecules of block and graft copolymers are molecules of a higher order; they consist of homopolymer subchains which are interconnected by chemical valence bonds. This structural com plexity is manifested in the unusual behavior of block and graft copolymers both in solution and in bulk. Many types of interac tions are possible in block and graft copolymers in the solid state. Polymer subchains of one molecule can interact with other polymer subchains which may belong to the same molecule or to different molecules. Since polymer chains of chemically different composition are usually incompatible, thermodynamically unfavorable as well as thermodynamically favorable interactions exist in the solid state. In solutions of block and graft copolymers, the sit uation becomes even more complex, because interactions between the solvent molecules and the various subchains of the copolymer mole cules occur in addition to the interactions between the polymer chains. This multitude of interactions gives rise to a wide spec trum of colloidal and morphological properties which have no paral lel in less complex polymer systems such as homopolymers or random copolymers. Research on the colloidal and morphological behavior of block and graft copolymers is a relatively new field of endeavor. It started in 1954, when F. M. Merrett fractionated mixtures of grafted na tural rubber with the corresponding homopolymers and observed that colloidal sols were formed at certain points during his fractional precipitations."
Natural polymers, such as proteins, starch, cellulose, hevea rubber, and gum which have been available for centuries, have been applied as materials for food, leather, sizings, fibers, structures, waterproofing, and coatings. During the past century, the use of both natural and syn thetic polymers has been expanded to include more intricate applications, such as membranes, foams, medicinals, conductors, insulators, fibers, films, packaging and applications requiring high modulus at elevated temperatures. The topics in this symposium which are summarized in this book are illustrative of some of the myriad applications of these ubiquitous mater ials. As stated in forecast in the last chapter in this book, it is cer tain that revolutionary applications of polymers will occur during the next decades. Hopefully, information presented in other chapters in this book will catalyze some of these anticipated applications. It is appropriate that these reports were presented at an American Chemical Society Polymer Science and Engineering Division Award Symposium honoring Dr. O.A. Battista who has gratifying to note that Phillips Pet roleum Company, which has paved the way in applications of many new poly mers, is the sponsor of this important award. We are all cheerfully expressing our thanks to this corporate spon sor and to Distinguished Professor Raymond B. Seymour of the University of Southern Mississippi who served as the organizer of this symposium and editor of this important book."
Th i s book had its orl gl n in the sympos i urn on "Polymers for Desalination" sponsored by the Division of Polymer Chemistry of the American Chemical Society and held in September, 1971 in Wash ington D. C. at the 162nd national meeting of the Society. However, the book is not simply the proceedings of that symposium. A num ber of additional papers were contributed by other workers in the field, and the original papers presented at the symposium have, for the most part, been expanded. The book thus represents a broad cross section of membrane research and development activities in the United States and abroad within the field of reverse osmosis. The purposes of the book are to bring attention to important new developments in this field, to suggest what the next generation of reverse osmosis equipment may look like, and to indicate where fur ther research and development are needed. The vast majority of the papers collected here represent work supported by the Office of Saline Water of the United States Department of the Interior, and the emphasis here is clearly on the application of the reverse os mosis process to water purification. However, many of the concepts, methods, and conclusions are expected to be useful in other areas of membrane science and technology."
The first concern of scientists who are interested in synthetic polymers has always been, and still is: How are they synthesized? But right after this comes the question: What have I made, and for what is it good? This leads to the important topic of the structure-property relations to which this book is devoted. Polymers are very large and very complicated systems; their character ization has to begin with the chemical composition, configuration, and con formation of the individual molecule. The first chapter is devoted to this broad objective. The immediate physical consequences, discussed in the second chapter, form the basis for the physical nature of polymers: the supermolecular interactions and arrangements of the individual macromolecules. The third chapter deals with the important question: How are these chemical and physical structures experimentally determined? The existing methods for polymer characterization are enumerated and discussed in this chapter. The following chapters go into more detail. For most applications-textiles, films, molded or extruded objects of all kinds-the mechanical and the thermal behaviors of polymers are of pre ponderant importance, followed by optical and electric properties. Chapters 4 through 9 describe how such properties are rooted in and dependent on the chemical structure. More-detailed considerations are given to certain particularly important and critical properties such as the solubility and permeability of polymeric systems. Macromolecules are not always the final goal of the chemist-they may act as intermediates, reactants, or catalysts. This topic is presented in Chapters 10 and 11."
Almost thirty years ago the author began his studies in colloid chemistry at the laboratory of Professor Ryohei Matuura of Kyushu University. His graduate thesis was on the elimination of radioactive species from aqueous solution by foam fractionation. He has, except for a few years of absence, been at the university ever since, and many students have contributed to his subsequent work on micelle formation and related phenomena. Nearly sixty papers have been published thus far. Recently, in search of a new orientation, he decided to assemble his findings and publish them in book form for review and critique. In addition, his use of the mass action model of micelle has received much criticism, especially since the introduction of the phase separation model. Many recent reports have postulated a role for Laplace pressure in micellization. Although such a hypothesis would provide an easy explanation for micelle formation, it neglects the fact that an interfacial tension exists between two macroscopic phases. The present book cautions against too ready an acceptance of the phase separation model of micelle formation. Most references cited in this book are studies introduced in small group meetings of colloid chemists, the participants at which included Professors M. Saito, M. Manabe, S. Kaneshina, S. Miyagishi, A. Yamauchi, H. Akisada, H. Matuo, M. Sakai, and Drs. O. Shibata, N. Nishikido, and Y. Murata, to whom the author wishes to express his gratitude for useful discussions.
From the symposium on Advances in Zeolites and Pillared Clays Synthesis, sponsored by the Petroleum Chemistry Division of the American Chemical Society experts from around the world review: You'll find everything you've ever wanted to know about zeolites and pillared clays: For the novice - how to information on zeolite synthesis. For the expert - a survey of advances in novel zeolites. The mechanism of zeolite crystallisation and crystal growth; spectroscopic characterization of reactants and reaction intermediates; chemistry of silicate solution and reaction effects on crystallization products; the role of organic additives in zeolite formation; novel synthesis methods and procedures for zeolites and pillared clays preparation; new pillaring agents and pillared products; delaminated clays.
Phase transfer catalysis or interfacial catalysis is a syn thetic technique involving transport of an organic or inorganic salt from a solid or aqueous phase into an organic liquid where reaction with an organic-soluble substrate takes place. Over the past 15 years there has been an enormous amount of effort invested in the development of this technique in organic synthe sis. Several books and numerous review articles have appeared summarizing applications in which low molecular weight catalysts are employed. These generally include either crown ethers or onium salts of various kinds. While the term phase transfer catalysis is relatively new, the concept of using a phasetrans fer agent (PTA) is much older Both Schnell and Morgan employed such catalysts in synthesis of polymeric species in the early 1950's. Present developments are really extensions of these early applications. It has only been within the last several years that the use of phase transfer processes have been employed in polymer synthesis and modification. Similarly, the use of polymer-bound phase transfer agents is also a recent development. These and related areas have nonetheless enjoyed explosive growth as mea sured by the number of publications and the variety of applica tions which have appeared. Several reviews dealing with these l 6 polymer-related investigations have been published."
Molecular systems are assemblies of molecules designed to possess special qualities and desired functionality. Such systems are important because they provide materials with novel properties, and they will be particularly useful for minimizing electronic devices. In this two volume work, the first volume, subtitled 'From Molecules to Molecular Systems', covered the fundamentals of molecular design, while volume 2 deals with the potential applications of molecular systems. Information transduction and energy conversion are the basis of any practical device, and these considerations, along with the required interconnections and interfaces, are analyzed to produce the architectural design for a molecular system. The preparation of molecular systems is also considered, including that of self-organizing molecular assemblies, ultrathin films, and ultrafine particles.
Most practitioners and students of polymer chemistry are familiar, in general terms at least, with the established methods of polymer synthesis - radical, anionic, cationic and coordination addition polymerization, and stepwise con densation and rearrangement polymerization. These methods are used to synthesize the majority of polymers used in the manufacture of commercially important plastics, fibres, resins and rubbers, and are covered in most introduc tory polymer chemistry textbooks and in most undergraduate and graduate courses on polymer science. Fewer polymer chemists, however, have much familiarity with more recent developments in methods of polymer synthesis, unless they have been specifically involved for some time in the synthesis of speciality polymers. These developments include not only refinements to established methods but also new mechanisms of polymerization, such as group transfer and metathesis polymerization and novel non-polymerization routes to speciality polymers involving, for example, the chemical modification of preformed polymers or the linking together of short terminally functionalized blocks." |
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