Polymers, main components of plastics and rubbers, are being discarded in increasing quantities. But this waste can also be considered as plastic gold'. Public concern, coupled with the inherent value of the material, means that recycling is imperative. The present book presents a survey of current knowledge in the form of case studies, including current legal and educational issues. Topics covered also include regulation and practice in NATO countries, the economics of recycling, the reprocessing of single polymers and mixtures, and future prospects and strategies. Audience: Vital reading for all polymer scientists, technicians and engineers.

The fouling of heat exchangers, reactors and catalysts remains one of the most urgent problems facing the process industries. Over the past ten years there has been limited research and investigation into the underlying mechanisms which give rise to this problem. For convenience, particularly in heat exchanger technology, the mechanisms involved have been subdivided into different subject areas. It is often the situation that individuals or groups of workers have concentra ted efforts in one or two of these specialist areas and there is a need to integrate the ideas across the whole spectrum of the subject. In addition, topics such as adhesion and surface phenomena have not been properly taken into account up till now in the assessment of the fouling processes. For this reason it was considered essential that the recognised experts from around the world, who are actively concerned with research, development and design in the fieId, should meet and exchange ideas and experience. Such a meeting was held at Alvor, Portugal, in May 1987, sponsored by the NATO Advanced St dy Institutes Programme. In order to obtain a common basis for the work of the Advanced Study Institute, the whole technological field was reviewed right from the basic concepts to the frontiers of present knowledge. Each invited contributor was asked to make an overall presentation covering his or her area of expertise."

Carbon filament, vapor grown carbon fibers and carbon nanotubes have been discovered to have remarkable properties, opening they way for their use in intriguing and novel applications in electronics, chemistry and materials science. There are many similarities between nanotubes and filaments, leading many researchers to critically compare the two materials, their production, and potential applications. The two materials are compared and contrasted in depth in the present book, which is a comprehensive review of current research activity, growth mechanisms, physical properties, industrial production, and applications. The structures are discussed using a unified approach, which helps to compare growth mechanisms, contrasting morphological differences, and detailing how novel properties depend on such differences.

Conventional synthetic materials, like metals, ceramics or glass, are usually isotropic substances, and their suitability for structural applications is achieved by morphological design and combination in the macroscopic scale. However, in modem engineering this is often not acceptable. As an alternative, the use of non-homogeneous, anisotropic materials, with significant stiffness and strength only in the directions these mechanical properties are really needed, can lead to enormous material (and weight) savings. This is the case of multiphase systems called composite materials. In these composites, different material parts are added and arranged geometrically, under clearly designed and controlled conditions. Usually, a structure of fibers provides strength and stiffness and a matrix helds them together, whilst providing the geometric form. Carbon fibers are among the high-performance fibers employed in these advanced structural composites, which are profoundly changing many of today's high technology industries. New research and development challenges in this area include upgrading the manufacturing process of fibers and composites, in order to improve characteristics and reduce costs, and modifying the interfacial properties between fibers and matrix, to guarantee better mechanical properties. The interdisciplinary nature of this "new frontier" is obvious, involving chemistry, materials science, chemical and mechanical engineering. Other topics, which more often are treated separately, are also important for the understanding of the processes of fiber production. Carbon filaments is one such topic, as the study of their mechanisms of nucleation and growth is clearly quite relevant to the production of vapour-grown carbon fibers.

Conventional synthetic materials, like metals, ceramics or glass, are usually isotropic substances, and their suitability for structural applications is achieved by morphological design and combination in the macroscopic scale. However, in modem engineering this is often not acceptable. As an alternative, the use of non-homogeneous, anisotropic materials, with significant stiffness and strength only in the directions these mechanical properties are really needed, can lead to enormous material (and weight) savings. This is the case of multiphase systems called composite materials. In these composites, different material parts are added and arranged geometrically, under clearly designed and controlled conditions. Usually, a structure of fibers provides strength and stiffness and a matrix helds them together, whilst providing the geometric form. Carbon fibers are among the high-performance fibers employed in these advanced structural composites, which are profoundly changing many of today's high technology industries. New research and development challenges in this area include upgrading the manufacturing process of fibers and composites, in order to improve characteristics and reduce costs, and modifying the interfacial properties between fibers and matrix, to guarantee better mechanical properties. The interdisciplinary nature of this "new frontier" is obvious, involving chemistry, materials science, chemical and mechanical engineering. Other topics, which more often are treated separately, are also important for the understanding of the processes of fiber production. Carbon filaments is one such topic, as the study of their mechanisms of nucleation and growth is clearly quite relevant to the production of vapour-grown carbon fibers.

The fouling of heat exchangers, reactors and catalysts remains one of the most urgent problems facing the process industries. Over the past ten years there has been limited research and investigation into the underlying mechanisms which give rise to this problem. For convenience, particularly in heat exchanger technology, the mechanisms involved have been subdivided into different subject areas. It is often the situation that individuals or groups of workers have concentra ted efforts in one or two of these specialist areas and there is a need to integrate the ideas across the whole spectrum of the subject. In addition, topics such as adhesion and surface phenomena have not been properly taken into account up till now in the assessment of the fouling processes. For this reason it was considered essential that the recognised experts from around the world, who are actively concerned with research, development and design in the fieId, should meet and exchange ideas and experience. Such a meeting was held at Alvor, Portugal, in May 1987, sponsored by the NATO Advanced St dy Institutes Programme. In order to obtain a common basis for the work of the Advanced Study Institute, the whole technological field was reviewed right from the basic concepts to the frontiers of present knowledge. Each invited contributor was asked to make an overall presentation covering his or her area of expertise."

Polymers, main components of plastics and rubbers, are being discarded in increasing quantities. But this waste can also be considered as plastic gold'. Public concern, coupled with the inherent value of the material, means that recycling is imperative. The present book presents a survey of current knowledge in the form of case studies, including current legal and educational issues. Topics covered also include regulation and practice in NATO countries, the economics of recycling, the reprocessing of single polymers and mixtures, and future prospects and strategies. Audience: Vital reading for all polymer scientists, technicians and engineers.

Carbon filament, vapor grown carbon fibers and carbon nanotubes have been discovered to have remarkable properties, opening they way for their use in intriguing and novel applications in electronics, chemistry and materials science. There are many similarities between nanotubes and filaments, leading many researchers to critically compare the two materials, their production, and potential applications. The two materials are compared and contrasted in depth in the present book, which is a comprehensive review of current research activity, growth mechanisms, physical properties, industrial production, and applications. The structures are discussed using a unified approach, which helps to compare growth mechanisms, contrasting morphological differences, and detailing how novel properties depend on such differences.