Aspects Of Polyurethanes

"Polyurethanes are formed by reacting a polyol (an alcohol with more than two reactive hydroxyl groups per molecule) with a diisocyanate or a polymeric isocyanate in the presence of suitable catalysts and additives. Because a variety of diisocyanates and a wide range of polyols can be used to produce polyurethane, a broad spectrum of materials can be produced to meet the needs of specific applications. During World War II, a widespread use of polyurethanes was first seen, when they were used as a replacement for rubber, which at that time was expensive and hard to obtain. During the war, other applications were developed, largely involving coatings of different kinds, from airplane finishes to resistant clothing. Subsequent decades saw many further developments and today we are surrounded by polyurethane applications in every aspect of our everyday lives. While polyurethane is a product that most people are not overly familiar with, as it is generally "hidden" behind covers or surfaces made of other materials, it would be hard to imagine life without polyurethanes."--Publisher's website

Polyurethanes are formed by reacting a polyol (an alcohol with more than two reactive hydroxyl groups per molecule) with a diisocyanate or a polymeric isocyanate in the presence of suitable catalysts and additives. Because a variety of diisocyanates and a wide range of polyols can be used to produce polyurethane, a broad spectrum of materials can be produced to meet the needs of specific applications. During World War II, a widespread use of polyurethanes was first seen, when they were used as a replacement for rubber, which at that time was expensive and hard to obtain. During the war, other applications were developed, largely involving coatings of different kinds, from airplane finishes to resistant clothing. Subsequent decades saw many further developments and today we are surrounded by polyurethane applications in every aspect of our everyday lives. While polyurethane is a product that most people are not overly familiar with, as it is generally "hidden" behind covers or surfaces made of other materials, it would be hard to imagine life without polyurethanes.

This book, cohesively written by an expert author with supreme breadth and depth of perspective on polyurethanes, provides a comprehensive overview of all aspects of the science and technology on one of the most commonly produced plastics. Covers the applications, manufacture, and markets for polyurethanes, and discusses analytical methods, reaction mechanisms, morphology, and synthetic routes Provides an up-to-date view of the current markets and trend analysis based on patent activity and updates chapters to include new research Includes two new chapters on PU recycling and PU hybrids, covering the opportunities and challenges in both

A comprehensive account of the physical / mechanical behaviour of polyurethanes (PU ́s) elastomers, films and blends of variable crystallinity. Aspects covered include the elasticity and inelasticity of amorphous to crystalline PUs, in relation to their sensitivity to chemical and physical structure. A study is made of how aspects of the constitutive responses of PUs vary with composition: the polyaddition procedure, the hard segment, soft segment and chain extender (diols and diamines) are varied systematically in a large number of systems of model and novel crosslinked andthermoplastic PUs. Results will be related to: microstructural changes, on the basis of evidence from x-ray scattering (SAXS and WAXS), and also dynamic mechanical analyses (DMA), differential scanning calorimetry (DSC) and IR dichroism. Inelastic effects will be investigated also by including quantitative correlations between the magnitude of the Mullins effect and the fractional energy dissipation by hysteresis under cyclic straining, giving common relations approached by all the materials studied. A major structural feature explored is the relationship between the nature of the hard segment (crystallising or not) and that of the soft segments. Crystallinity has been sometimes observed in the commercial PUs hard phase but this is usually limited to only a few percent for most hard segment structures when solidified from the melt. One particular diisocyanate, 4,4’-dibenzyl diisocyanate (DBDI) that, in the presence of suitable chain extenders ( diols or diamines), gives rise to significant degrees of crystallinity [i-iii] and this is included in the present work. Understanding the reaction pathways involved, in resolving the subtle morphological evolution at the nanometre level, and capturing mathematically the complex, large-deformation nonlinear viscoelastic mechanical behaviour are assumed to bring new important insights in the world basic research in polyurethanes and towards applied industrial research in this area.

Contains 25 reports of significant aspects of polyurethane technology and specific recent developments of importance. Historical, technical, economic, and marketing developments are covered. Technical advances treated include advances in polyols and polyurethane additives such as catalysts, surfacta

Handbook of Polyurethanes serves as the first source of information of useful polymers. This new book thoroughly covers the entire spectrum of polyurethanes - from current technology to buyer's information. Discussions include: block and heteroblock systems rubber plasticity structure-property relations microphase separation catalysis of isocyanate reactions synthesis of polyurethanes for thermoplastics, thermosets, and curable compositions by either heat or U.V. energy biomedical applications of urethane elastomers castables, sealants, and caulking compounds flexible and semi-flexible foams health and safety This handbook compiles data from many sources, exhaustively illustrating the complex principles involved in polyurethane chemistry and technology. Handbook of Polyurethanes represents invaluable information for corporations, universities, or independent inventors.

Applications of Polyurethanes in Medical Devices provides detailed coverage of polyurethane (PU) chemistry, processing and preparation for performant medical devices. Polyurethanes have found many uses in medical applications, due to their biocompatibility, biostability, physical properties, surface polarity, and the ability to suit the field of application. This book enables the reader to understand polyurethane and how this valuable material can be used in medical devices. Sections cover the chemistry, structure, and properties of polyurethane, with in-depth sections examining raw materials, reaction chemistry, synthesis techniques, reaction kinetics, material microstructure, and structure-property relationships. Subsequent chapters demonstrate how polyurethane can be utilized in medical device applications, examining biological properties, rheology and processing before methodical coverage explains how polyurethane may be used for each category of medical device. Finally, future directions, and safety and environmental aspects, are covered. Bridges the gap between polyurethane chemistry, processing and preparation for cutting-edge medical device applications Includes in-depth coverage of polyurethane, covering raw materials, chemistry, synthesis techniques, reaction kinetics, properties and microstructural analysis Takes a valuable and practical approach, addressing manufacturing issues and using testing and modeling to solve problems encountered in processing

User-friendly, even for those with limited knowledge of chemistry, it contains clear details of processing, applications, and safety. New to this edition is an appendix covering the considerable progress that has taken place since 1987, including the development of alternatives for chlorofluorocarbons (CFCs) and the advent of polyurea elastomers.