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Books > Science & Mathematics > Chemistry > Organic chemistry > Polymer chemistry
New technologies constantly generate new demands for exotic materials to be used in severe environments. The rapid developments of aerospace industries during the last two decades have required new materials to survive extreme high and low temperatures and various radiations. The exploration of new energy sources, e.g., solar and geothermal, has led us to develop new solar collectors and geothermal devices. Even the search for new oils has demanded that we study the corrosive environment of oil fields. In the telecommunication industries, optical fibers have been adopted broadly to replace metallic conductors. However, none of the optical fibers can survive abrasion or corrosion without the application of a coating material. For microelectronics, protection in terms of coatings and encapsulants is deemed necessary to prevent corrosion. One of the major causes of corrosion has been shown to be water which appears to be abundant in our earthly environments. Water can attack the bulk adhesive (or sealant), the interface, or the adherend. Water can also cause delamination of coating film, and it is definitely the major ingredient in causing cathodic or anodic corrosion. Thus, water becomes the major obstacle in solving durability problems of various materials in harsh environments.
Targeting of drugs via carrier systems to sites in the body in need of pharmacologic intervention is a rapidly growing area of research in the treatment or prevention of disease. It has evolved from the need to preferentially deliver drugs, enzymes, vitamins, hormones, antigens, etc. to target cells and organs so as to avoid toxicity, waste of drugs through premature secretion or inactivation and at the same time render treatment more convenient and cost-effective. A wide assortment of naturally occ urring or semi-synthetic drug carriers (e. g. antibodies, glycoproteins, lectins, peptide hormones, cells and liposomes), their inter action with relevant receptors and mediation of optimal pharmacological action were discussed in the two previous NATO Advanced Studies Institutes (ASI) of this series, "Targeting of Drugs" and "Receptor-Mediated Targeting of Drugs," the proceedings of wh ich were published by Plenum in 1982 and 1984 respectively. This book contains the proceedings of the 3rd NATO ASI "Targeting of Drugs with Synthetic Systems" held as be fore at Cape Sounion, Greece during 24 June-5 July 1985. It deals mostly with man-made carriers such as a variety of polymers, matrices, liposomes and other colloidal micro particles. The twenty chapters discuss the interaction of such carriers with the biological milieu, approaches to bypass the reticuloendothelial system (or, when needed, take advantage of its interception of carriers to optimally deliver drugs to phagocytes) and ways to improve delivery to specific cells, often with the help of carrier-linked ligands."
Ring-Opening Polymerization of Bicyclic and Spiro Compounds The Development of Well-defined Catalysts for Ring-Opening Olefin Metathesis CaptodativeOlefins in Polymer Chemistry Synthesis and Properties of Fluorinated Diols Synthesis and Properties of Fluorinated Telechelic Monodis- persedCompounds Synthesis and Metal Complexation of Poly(ethyleneimine) and Derivatives Oxidation of Hydrocarbon Polymers
The basis for this volume is the 11th Symposium on Analytical
Ultracentrifugation held in March 25-26, 1999 at the University of
Potsdam, Germany. This book presents a comprehensive collection of
33 contributions from leading scientists in this field including:
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1. K. Zamaraev, R. Khairutdinov: Photoinduced Electron Tunneling Reactions in Chemistry and Biology 2. P. Suppan: The Marcus Inverted Region 3. H.D. Roth: Structure and Reactivity of Organic Radical Cations
Gellan gum, a microbial polysaccharide, consisting of tetra-saccharide unit, glucose, glucuronic acid, glucose and rhamnose, forms a transparent gel which is heat-resistant in the presence of divalent cations. Since 1989, the collaborative research group was organised in the Research Group of Polymer Gels affiliated to the Society of Polymer Science, Japan, consisting of various laboratories with different disciplines to clarify the mechanism using the common purified sample. This special issue contains 19 papers on the molecular conformation, gel-sol transition, interaction of gellan and water, cations and sugar, based on rheology, NMR, ESR, DSC, light scattering, osmotic pressure, small angle x-ray scattering, dielectric measurement, atomic force microscopy and the industrial application of gellan gum presented at the 4th International Conference on Hydrocolloids - OCUIS '98 by the collaborative group members and by international experts.
In the early 1980s capillary liquid chromatography was being established; it was a period in which only a few research groups published a relatively small number of papers on the subject. In terest has since taken off, and a period of intense development, to which no end is yet in sight, is now upon us. More investiga tors and instrument-making firms are now entering the field. This greater interest has resulted in the rapid appearance of two collec tions [1, 2] and a series of topical reviews [3-6]. However, it could hardly be said that all the problems in this area have been formulated, let alone solved. The preparation of very efficient - open tubular or packed - microbore columns, for example, remains more an art than a science, while the relation ship between radial and longitudinal mass transfer, and the effect of transcolumn velocity profiles on chromatographic efficiency, have been very poorly studied. Indeed, recent publications on these subjects have sometimes, far from clarifying matters, only muddied them further. Many instrument-making firms are trying to unify their equip ment so that it is suitable for microbore, conventional (analytical), and preparative liquid chromatography. This approach has not real ized the full potential of capillary chromatography, and there also remains room for improving the performance of capillary columns.
This volume "Deformation of Ceramic Materials II" constitutes the proceedings of an international symposium held at The Pennsyl vania State University, University Park, PA on July 20, 21, and 22, 1983. It includes studies of semiconductors and minerals which are closely related to ceramic materials. The initial conference on this topic was held in 1974 at Penn State and the proceedings were published in the volume entitled "Deformation of Ceramic Materials." This conference emphasized the deformation behavior of crystals and po1ycrysta11ine and polyphase ceramics with internationally recognized authorities as keynote lecturers on the major subtopics. Several papers dealing with cavity nucleation and creep crack growth represent a major new research thrust in ceramics since the first conference. This collection of papers represents the state-of-the art of our understanding of the plastic deformation behavior of ceramics and the crystals of which they are composed. We are grateful for the suggestions of our International Advisory Committee .in recommending experts in their respective countries to participate. We are particularly grateful that the organizers of the previous Dislocation-Point Defect Interaction Workshops agreed to participate in the Penn State Symposium as an alternative at the suggestion of Prof. A. H. Heuer. We acknowledge the financial support of the National Science Foundation for this conference."
Integral, or structural, foams are one of the most remarkable materials that have been developed over the last fifteen years. As with all rapidly growing fields, the terminology seems to have grown even faster. Thus there are two names for the material structure itself. In the United States and in Japan the term for these plastics is Structural Foams, whereas in Europe and the USSR the term used is usually Integral Foams. We have adhered to the European term in the text and hope our colleagues will bear with us. Integral foams have a specific structure: a cellular core that gradually turns into a solid skin. The skin gives the part its form and stiffness, while the cellular core contributes to the very high strength-to-weight values of the material. These are higher than those of some unfoamed plastics and metals. The sandwich-like structure with its unique mechanical properties was prompted by nature. Wood and bone are strong and light-weight natural materials having a cellular structure. Since the sandwich-like structure of the integral foams resembles that of natural wood, the foams are often referred to as artifical wood or plastic wood, thereby emphasizing not only the formal structural similarity of these materials, but also one of the main functional applications of integral foams - replacement of wooden articles in various fields of engineering and construction.
The series of Conferences on the Spectroscopy of Biological Molecules aims to stimulate research and development in this area of Science. The relationship between the structure and the biological activity of such materials as proteins, lipids, and nucleic acids is fundamental. The 5th European Conference on the Spectroscopy of Biological Molecules (ECSBM) is held at the Hotel Poseidon Club, Loutraki, Greece, on 5-10 September 1993. The scientific contents are remained the same as in the past conferences. Emphasis is given to vibrational spectroscopy, mainly infrared and Raman applied to the study of structure and dynamics of proteins, nucleic acids, porphyrins, carbohydrates, membranes, etc. Most of the contributions describe molecular dynamics and excitation processes, in particular the electronic-vibrational excitations, which are studied by Fr-Raman, Fourier Transform Infrared (Fr-IR) coupled often with microscopy and chromatography. Contributions also include Fr-Raman and FT-IR instrumentation and new developments in this area, and applications in Biology and Medicine. Furthermore, there is a plenary lecture in Mass Spectrometry and its applications in biomedical analysis, and a session devoted to Nuclear Magnetic Resonance (NMR) and its application in the study of biological molecules. Several contributions are devoted to other methods, such as CD, optical absorption, fluorescence and molecular graphics simulations. This volume of ECSBM contains shon articles by the invited and contributed lectures as well as from the Poster presentations from many European and non-European countries.
Modern Synthetic and Application Aspects of Polysilanes: An
Underestimated Class of Materials?, by A. Feigl, A. Bockholt, J.
Weis, and B. Rieger;
Since the discovery that polymer single crystals are composed of chain folded macromolecules in 1957, the crystallization of polymers has attracted considerable interest and still provides fascinating and fruitful areas of research. Only a few books have been fully devoted to the crystallization of polymers in the past. This book contains the proceedings of the NATO ARW devoted to the `Crystallization of Polymers' which took place in September 1992 at the University of Mons-Hainaut (Belgium). In view of the variety of papers devoted to the crystallization of polymers, this book will be used in the next few years as a reference book for scientists concerned in the field of polymer physical chemistry. Crystallization of Polymers is mainly devoted to the experimental and theoretical study of the crystallization of synthetic polymers. As a kinetic study of the growth of polymer crystals should always be preceded by a morphological or a structural investigation, the structure, the morphology of polymer crystals and more particularly the lamellar and supralamellar organizations, as well as the nature of the crystal amorphous interface are reviewed and discussed.
Photochromic polymer systems are of two main types: those which are merely solid solutions of photochromes in polymeric matrices and those custom-designed polymers which inherently exhibit photochromism. This book provides a concise review of developments in such systems over the past two decades. The coverage has been limited specifically to applied sys tems, or areas with potential applications, although over 500 references cite much of the literature on the fundamentals of the subject. In general, non-biological organic photochromism in organic matrices has been covered. However, the unique properties of polysiloxanes merit special mention in Chapter 4, because of the attributes that such inorganic polymers can provide in certain systems such as liquid crystalline photochromic polymers, where two extremely interesting phenomena are combined. In addition to outlets in polarization-sensitive holographic recording media, such materials exhibit interesting non-linear optical effects suitable for optical switching and rheo-optical phenomena which may find application in mechano-optic transduction. Within this framework examples of all the important photochromic mechanisms are covered by authors from both the industrial and the academic sectors. Given the photonic nature of the phenomenon under discussion, it is not surprising that many optical applications have been proposed. It is perhaps more surprising, however, that, until recently, no large scale markets had been identified that could commercially exploit photochromic phenomena."
This book represents the proceedings of the First International Conference on Frontiers of Polymer Research held in New Delhi, India during January 20-25, 1991. Polymers have usually been perceived as substances to be used in insulations, coatings, fabrics, and structural materials. Defying this classical view, polymers are emerging as a new class of materials with potential applications in many new technologies. They also offer challenging opportunities for fundamental research. Recognizing a tremendous growth in world wide interest in polymer research and technology, a truly global "1st International Conference on Frontiers of Polymer Research" was organized by P. N. Prasad (SUNY at Buffalo), F. E. Karasz (University of Massachusetts) and J. K. Nigam (Shriram Institute for Industrial Research, India). The 225 participants represented 25 countries and a wide variety of academic, industrial and government groups. The conference was inaugurated by the Prime Minister of India, Mr. Chandra Shekhar and had a high level media coverage. The focus of the conference was on three frontier areas of polymer research: (i) Polymers for photonics, where nonlinear optical properties of polymers show great promise, (ii) Polymers for electronics, where new conduction mechanisms and photophysics have generated considerable enthusiasm and (iii) High performance polymers as new advanced polymers have exhibited exceptionally high mechanical strength coupled with light weight.
This handbook provides essential practical information for Industrial and State Control Laboratories and others concerned with ensuring compliance with European Community directive 90/128/EEC relating to plastic materials and articles intended to come into contact with foodstuffs. This new book on additives used in plastics for food contact can be seen as a companion to Spectra for the Identification of Monomers in Food Packaging (Kluwer Academic Publishers, 1993). The handbook begins with a chapter describing the legal framework and the implementation of the European legislation. There is a brief description of the Dutch fast method to test compliance with legislation using this handbook. Then, a collection of spectra is given for the identification of a hundred of the most important additives used in plastic packaging and coatings. These additives were selected from Synoptic Document N. 7 after extensive consultation with researchers in the field and with representatives from European industry. For every additive there is an entry in the handbook giving the structural formula, CAS and PM number and trivial name, together with information on physical characteristics, the food contact uses of the derived plastic materials. There is a brief description of the analytical approach for testing compliance with SML or QM limits and reference to the literature including European research projects. FT-IR, MS and 1H-NMR spectra are proved in standard format for each substance, and gas-chromatographic retention data are provided as a help in identification. Most of the additives listed in this volume will be made available on request as reference substances as either the pure substance or as a calibrant solution.
Existing surfactants directories tend to focus on product identification by tradename, producer or chemical type, enabling the user only to identify product equivalents and surfactant suppliers. Application information, where available, is usually scant or given as a footnote. This new directory approaches the identification of surfactants primarily from the applications standpoint. Hence the formulator or end-user can readily assess the products available for use in a particular industry sector and select materials giving the required surface active properties. For example, a formulator of agrochemicals for crop protection can turn to the section which refers to surfactants for use in the agrochemical industry and then easily identify a wetter/dispersant system for the production of water dispersible granules. Information is presented in an alternative format in the second part of the directory, which will help the user to identify swiftly products for a particular application by surface active properties. It is difficult, if not impossible, to identify an industry which does not directly or indirectly utilise surfactants. Therefore it has proved necessary to simplify industry classifications to encompass a variety of uses under broader sector titles. The industry classifications adopted here have been used in many previous publications and papers, and define as accurately as possible the major industries and applications serviced by the surfactant industry. The editors have been particularly pleased with the support and response of the industry in the supply of data."
In order to adapt the properties of living materials to their biological functions, nature has developed unique polyelectrolytes with outstanding physical, chemical and mechanical behavior. Namely polyampholytes can be suitable substances to model protein folding phenomenon and enzymatic activity most of biological macromolecules due to the presence of acidic and basic groups. The ability of linear and crosslinked amphoteric macromolecules to adopt globular, coil, helix and stretched conformations and to demonstrate coil-globule, helix-coil phase transitions, and sol-gel, collapsed expanded volume changes in relation to internal (nature and distribution of acid and base substituents, copolymer composition, hydrophobicity etc. ) and external (pH, temperature, ionic strength of the solution, thermodynamic quality of solvents etc. ) factors is very important and constantly attracts the attention of theorists and experimentalists because the hierarchy of amphoteric macromolecules can repeat, more or less, the structural organization of proteins. That is why polyampholytes fall within eyeshot of several disciplines, at least polymer chemistry and physics, molecular biology, colloid chemistry, coordination chemistry and catalysis. The main purpose of this monograph is to bridge the gap between synthetic and natural polymers and to show a closer relationship between two fascinating worlds. The first chapter of the book acquaints the readers with synthetic strategy of "annealed", "quenched" and "zwitterionic" polyampholytes. Radical copolymerization, chemical modification and radiation-chemical polymerization methods are thoroughly considered. Kinetics and mechanism of formation of random, alternating, graft, di-block or tri-block sequences is discussed. The second chapter deals with behavior of polyampholytes in solutions.
For several decades, polymer science has sought to rationalize the mechanical and thermodynamic properties of polymer networks largely within the framework of statistical thermodynamics. Much of this effort has been directed toward the rubbery rather than the glassy state. It is generally assumed that networks possess an av erage composition to which average properties may be assigned; from such a continuum view, a powerful analysis of such properties as modulus, swelling, birefringence and thermoelasticity has emerged. In the years following the rise of polymer characterization (the late 40's and early 50's), many scientists began to study ap parent relations between the properties of linear polymer molecules and the networks obtainable therefrom. This search was also stimu lated by the wide range of applications of polymer networks in com mercial elastomers, thermosets and coatings. Frequently, these data were confidently matched with curves obtained from statisti cally describable models of networks of ghost chains, uniformly distributed in space. More recently, it has become apparent that polymer chains in networks are not as ideal as assumed in the formulation of statis tical models, and there has been a shift in emphasis towards the less than ideal, perturbed and possibly inhomogeneous networks which are more frequently encountered in practice. The continuum approach, however, had to be developed before inhomogeneous systems could be described; the present volume, therefore, contains both views."
Over the past decade high performance computing has demonstrated the ability to model and predict accurately a wide range of physical properties and phenomena. Many of these have had an important impact in contributing to wealth creation and improving the quality of life through the development of new products and processes with greater efficacy, efficiency or reduced harmful side effects, and in contributing to our ability to understand and describe the world around us. Following a survey ofthe U.K.'s urgent need for a supercomputingfacility for aca demic research (see next chapter), a 256-processor T3D system from Cray Research Inc. went into operation at the University of Edinburgh in the summer of 1994. The High Performance Computing Initiative, HPCI, was established in November 1994 to support and ensure the efficient and effective exploitation of the T3D (and future gen erations of HPC systems) by a number of consortia working in the "frontier" areas of computational research. The Cray T3D, now comprising 512 processors and total of 32 CB memory, represented a very significant increase in computing power, allowing simulations to move forward on a number offronts. The three-fold aims of the HPCI may be summarised as follows; (1) to seek and maintain a world class position incomputational scienceand engineering, (2) to support and promote exploitation of HPC in industry, commerce and business, and (3) to support education and training in HPC and its application.
These volumes, 9 and 10, of Fracture Mechanics of Ceramics constitute the proceedings of an international symposium on the fracture mechanics of ceramic materials held at the Japan Fine Ceramics Center, Nagoya, Japan on July 15, 16, 17, 1991. These proceedings constitute the fifth pair of volumes of a continuing series of conferences. Volumes 1 and 2 were from the 1973 symposium, volumes 3 and 4 from a 1977 symposium, and volumes 5 and 6 from a 1981 symposium all of which were held at The Pennsylvania State University. Volumes 7 and 8 are from the 1985 symposium which was held at the Virginia Polytechnic Institute and State University. The theme ofthis conference, as for the previous four, focused on the mechanical behavior ofceramic materials in terms of the characteristics of cracks, particularly the roles which they assume in the fracture processes and mechanisms. The 82 contributed papers by over 150 authors and co-authors represent the current state of that field. They address many of the theoretical and practical problems ofinterest to those scientists and engineers concerned with brittle fracture.
Polymer composites represent materials of great and of continuously growing importance. Their potential for application appears to be limitless. They have been the subject of numerous studies both at academic and industrial levels. Much progress has been made in the incisive formulation of composites; sophisticated methods of property evaluation have been developed in the past decade and many, largely empirical solutions have been proposed to resolve the problem of their long-term performance under typical conditions of use (i. e. the use of silane or titane coupling agents to enhance adhesion within composite materials). Assuredly one of the most essential factors in the performance of these systems is the condition of the interface and interphase among the constituents of a given system. It has become clear that it is the interface/interphase, and the interactions which take place in this part of a system, which determine to a significant degree the initial properties of the material. In order to achieve leadership in the formulation and application of polymer composites, it is evident that in depth understanding of interfacial and interphase phenomena becomes a prerequisite.
Approximately half of the world production of the petrochemical industry (more than 100 million tonnes) is in the form of polymers, yet it would probably surprise most people to learn how much their lifestyle depends on polymers ranging, as they do, from detergents, kitchenware and electrical appliances to furnishings and a myriad other domestic goods. Still less are they likely to be aware of the extensive part they play in engineering applications for mechanical machine components and advanced high performance aircraft. This versatility derives from the fact that polymeric materials are made up of a range of molecules of varying length, whose properties are related to molecular structure and the proportions of the chains in the mixture. For example, polypropylene is a commodity polymer which is produced in hun dreds of different grades to meet specific market requirements. This depends on the catalyst as well as the operating conditions and reactor design. A major area for growth is in substituting polymers for conventional materials such as ceramics and metals. Not only can they match these materials in terms of mechanical strength and robustness but they have very good resistance to chemical attack. Polyamides, for example, are widely used for car bumpers and new polymers are being developed for engine manifolds and covers. In 1993 there is, typically, 100 kg of various polymers used in cars and this is continually increasing, giving a net weight reduction and hence better fuel economy." |
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