موضوعات
آموزش و پرورش
ادبیات و زبان
پزشکی، دندانپزشکی و داروسازی
تاریخ و جغرافیا
داستان و رمان
دیگر
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ریاضیات و آمار
سلامتی، تناسب اندام و رژیم غذایی
شیمی و پلیمر
علوم اجتماعی و حقوق
علوم زیستی و بیوتکنولوژی
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کامپیوتر و اینترنت
کتابهای کودکان و داستان
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کشاورزی و دامپزشکی و غذا
معماری
مهندسی و فناوری
هنر و تئاتر
محصولات
Structured Fluids: Polymers, Colloids, Surfactants - Original PDF
نویسندگان: خلاصه: Over the last thirty years, the study of liquids containing polymers, surfactants, or colloidal particles has developed from a loose assembly of facts into a coherent discipline with substantial predictive power. These liquids expand our conception of what condensed matter can do. Such structured-fluid phenomena dominate the physical environment within living cells. This book teaches how to think of these fluids from a unified point of view showing the far-reaching effects of thermal fluctuations in producing forces and motions. Keeping mathematics to a minimum, the book seeks the simplest explanations that account for the distinctive scaling properties of these fluids. An example is the growth of viscosity of a polymer solution as the cube of the molecular weight of the constituent polymers. Another is the hydrodynamic radius of a colloidal aggregate, which remains comparable to its geometrical radius even though the density of particles in the aggregate becomes arbitrarily small. The book aims for a simplicity, unity and depth not found in previous treatments, and includes numerous figures, tables and problems. It will be an ideal textbook for teaching undergraduates in physical science how to understand soft matter, but will also be of interest to industrial scientists, who want to gain a broader understanding of soft matter systems
Laser Application of Polymers - Original PDF
نویسندگان: خلاصه: Abstract Laser ablation of polymers has been studied with designed materials to evaluate the mechanism of ablation and the role of photochemically active groups on the ablation process, and to test possible applications of laser ablation and designed polymers. The incorporation of photochemically active groups lowers the threshold of ablation and allows high-quality structuring without contamination and modification of the remaining surface. The decomposition of the active chromophore takes place during the excitation pulse of the laser and gaseous products are ejected with supersonic velocity. Time-of-flight mass spectrometry reveals that a metastable species is among the products, suggesting that excited electronic states are involved in the ablation process. Experiments with a reference material, i.e., polyimide, for which a photothermal ablation mechanism has been suggested, exhibited pronounced differences. These results strongly suggest that, in case of designed polymers which contain photochemically active groups, a photochemical part in the ablation mechanism cannot be neglected. Various potential applications for laser ablation and the special photopolymers were evaluated and it became clear that the potential of laser ablation and specially designed material is in the field of microstructuring. Laser ablation can be used to fabricate three-dimensional elements, e.g., microoptical elements
Alkylene Oxides and Their Polymers - Original PDF
نویسندگان: خلاصه: The poly(alkylene oxide)s are linear or branched-chain polymers that contain ether linkages in their main polymer chain structure and are derived from monomers that are vicinal cyclic oxides, or epoxides, of aliphatic olefins, principally ethylene and propylene and, to a much lesser extent, butylene. These polyethers are commercially produced over a range of molecular weights from a few hundred to several million for use as functional materials and as intermediates. Lower polymers are liquids, increasing in viscosity with molecular weight. The high polymers can be thermoplastic. Solubilities range from hydrophilic water-soluble polymers that are principally derived from ethylene oxide, to hydrophobic, oil-soluble polymers of propylene oxide and butylene oxide. A wide variety of copolymers is produced, both random copolymers and block copolymers. The latter may be used for their surface-active characteristics.
Absorbable biodegradable polymers - Original PDF
نویسندگان: خلاصه: Egyptians sutured wounds as early as 3500 B.C. using a variety of natural polymers including treated intestines, which are the early versions of collagen-based surgical gut sutures.1 Synthetic, absorbable polyesters based on 2-hydroxyacetic acids were developed for preparing less tissue reactive alternatives to surgical gut sutures in the early 1970s. In addition to collagenbased polymers, other natural, absorbable polymers, such as albumin, chitosan, and hyaluronic acid and derivatives thereof have been used for many pharmaceutical and biomedical applications for several decades.2 Of these polymers, the application of chitosan and hyaluronic acid–based polymers has received a great deal of attention in the past 15 years for use in controlled drug delivery systems, tissue repair, tissue engineering, and controlling certain biological events.
Handbook of Biodegradable Polymers - Original PDF
نویسندگان: خلاصه: Biodegradable polymers are niche market materials finding focused applications, including agricultural applications such as mulch films, flowerpots and controlled-release fertilisers and packaging items such as carrier bags and food wrapping and containers. They have the potential to provide a solution to a range of environmental concerns: decreasing availability of landfill space, declining petrochemical sources, and also offer an alternative option to recycling. Rapra's Handbook of Biodegradable Polymers is a complete guide to the subject of biodegradable polymers and is ideal for those new to the subject or those wanting to supplement their existing knowledge. The book covers the mechanisms of degradation in various environments, by both biological and non-biological means, and the methods for measuring biodegradation. The degree and rate of biodegradation is dependent on the chemical composition of the polymer and its working environment, and so there is no single optimal method for determining biodegradation. This handbook provides discussion of international and national standards and certification procedures developed to ensure accurate communication of a material's biodegradability between producers, authorities and consumers. The book goes on to consider the characteristics, processability and application areas for biodegradable polymers, with key polymer family groups discussed.
Liquid Crystalline Polymers - Original PDF
نویسندگان: خلاصه: As we know, there are three basic states of matter, solid, liquid, and gaseous states. These states of matter can be transformed into each other at appropriate conditions. In the solid state (generally meaning the crystalline state), the building blocks, such as atoms, or molecules, or clusters of molecules are packed closely and regularly, forming a crystal lattice. The X-ray diffraction of the state shows many regular diffraction spots. Over 95% of matter on the earth exist in the form of the crystalline state. The types of crystal structure are enormous. The physical properties of crystals are basically anisotropic. The crystals have a constant melting temperature (except for amorphous solids).
Macromolecules Containing Metal and Metal-Like Elements, Transition Metal-Containing Polymers - Original PDF
نویسندگان: خلاصه: Transition metal-containing macromolecules come in a wide variety of structures. While volume 5 of this series dealt with metal coordination polymers, in this book we focus on transition metal-containing polymers where the metal is bonded to at least one organic group through σ- and/or π-bonds. Many of the macromolecules covered in this volume are often referred to as organometallic polymers. The term organometallic compound refers to compounds that contain at least one metal–carbon (M–C) bond, whether the bond is σ or π or some combination of both types of bonding.
Crystallization of polymers. Volume 1, Equilibrium concepts - Original PDF
نویسندگان: خلاصه: Polymers of high molecular weight have now been accepted as respectable members of the molecular community. This situation was not always true.(1) It is now recognized, however, that polymer molecules possess the unique structural feature of being composed of a very large number of chain units that are covalently linked together. This property is common to all macromolecules despite their diverse origin, their widely differing chemical and stereochemical structures and uses and function. It is, therefore, possible to study this class of substances from a unified point of view that encompasses the relatively simpler polymers prepared in the laboratory, as well as the more complex ones of nature. The characteristic thermodynamic, hydrodynamic, physical, and mechanical properties possessed by high polymeric substances can be explained, in the main, by their covalent structure and the attendant large size of the individual molecules.
Synthetic Polymers for Biotechnology and Medicine - Original PDF
نویسندگان: خلاصه: One of the most powerful group of chemicals in the body are organic compounds collectively referred to as hormones. The glands responsible for the production and release of hormones comprise the endocrine system. Endocrine activities have been identified in certain organs, such as the heart, kidneys, duodenum, liver and the islets of Langerhans in the pancreas (which contains the insulin gland), which are normally associated with other system functions. There have been numerous attempts to replace organ function using cell transplantation including direct injections of dissociated cells into organs such as the liver, kidney or spleen.1-5 Subcutaneous and intraperitoneal routes have also been evaluated.6-10 More recent investigations have applied extracellular matrix polymers as structural supports for cell transplantation and immunoprotection.11,12 Potential medical applications of such “artificial cells” or “tissue engineered” organoids include an extracorporeal bioartificial liver for detoxification,2 artificial red blood substitutes,13 the extracorporeal artificial kidney for hemodialysis,14 immunosorbents15 and drug delivery systems.16The transplantation of immunoisolated (microencapsulated) cells represents another emerging area in biotechnology research and commercialization. Under such a scenario, the encapsulated cells, which could be a xenograft, would be hidden from the immune system of the body, but would still be able to respond to extracellular stimuli (e.g., blood glucose), with the required hormone, in the case of diabetes therapy insulin, secreted into the systemic circulation. Other applications of the microencapsulation concept include the encapsulation of genetically modified cells, which represents a novel approach to somatic gene therapy.17 This chapter will review recent advances in cell encapsulation from material science, technological and tissue-related perspectives. Cell coating, microencapsulation devices and bioartificial organs will be discussed with the artificial pancreas and treatment of diabetes used as a case study denominator throughout the review.
Adhesives, Sealants, and Coatings for Space and Harsh Environments - Original PDF
نویسندگان: خلاصه: 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.آیا کتاب مورد نظر هنوز بر روی سایت قرار نگرفته است؟ جای نگرانی نیست! کافی است بر روی گزینه سفارش کتاب کلیک کرده و درخواست خود را ثبت کنید. در کمتر از چند ساعت کتاب شما را آماده خواهیم کرد.