1,721,028 research outputs found
The instant expert: plastics, processing and properties
No full text"Plastics - they are everywhere." The first sentence of this book hints at the problem it seeks to address. The shear diversity of plastics materials has led to their use in products as varied as disposable packaging, life-saving medical devices, giant wind-turbine blades and tiny electronic components. Their prices and properties vary as widely, and they can be moulded, extruded, blown, formed, and shaped in many other ways. Traditionally made from petrochemicals, designers can now also choose from a range of natural materials. Performance will depend on chemical constitution, but also on the selection of processing aids and property modifiers which can be added to the basic material. For years, people have asked for a simple book to help them understand this complex subject. This is that book! Managers, sales personnel, industry newcomers, designers and end-users are all confronted with a bewildering range of technology and terminology by their colleagues, customers and suppliers. The Instant Expert: Plastics, Processing and Properties provides clear descriptions of the wide range of plastic materials, and explanations of the basic shaping and finishing processes. The author also talks about materials properties and testing, and provides some simple examples of why particular plastics are used in common or more challenging applications. Common abbreviations are explained. Readable from cover-to-cover, or easily referred to when questions arise, this book will be indispensible
Management, recycling and reuse of waste composites
No full textThis authoritative reference work provides a comprehensive review of the management, recycling and reuse of waste composites. These are issues which are of increasing importance due to the growing use of composites in many industries, increasingly strict legislation and concerns about disposal of composites by landfill or incineration. Part one discusses the management of waste composites and includes an introduction to composites recycling and a chapter on EU legislation for recycling waste composites. Part two reviews thermal technologies for recycling waste composites with chapters on pyrolysis, catalytic transformation, thermal treatments for energy recovery and fluidized bed pyrolysis. Part 3 covers mechanical methods of recycling waste composites. This section includes chapters on additives for recycled plastic composites, improving mechanical recycling and the quality and durability of mechanically recycled composites. Parts 4 discusses improving sustainable manufacture of composites, with chapters on environmentally-friendly filament winding of FRP composites, process monitoring and new developments in producing more functional and sustainable composites. Part 5 gives a review of case studies including end-of-life wind turbine blades, aerospace composites, marine composites, composites in construction and the recycling of concrete. With its distinguished editor and international team of contributors, Management, recycling and reuse of waste composites is a standard reference for anyone involved in the disposal or recycling of waste composites
Plastic recycling
No full textThis review covers the options for recycling of plastic waste and provides a general overview of the main issues associated with plastic disposal. It provides a summary of the quantities and type of plastics in the waste stream and also the main effects of recycling on the plastic material itself. The four types of recycling: primary, secondary, tertiary and quarternary, the requirements each places on the feed stock, and the uses of each are given
Injection moulding : a practical guide
No full textThis revised 3rd edition details the factors involved in the injection moulding process, from material properties and selection to troubleshooting faults, and includes the equipment types currently in use and machine settings for different types of plastics. Since material flow is critical in moulding, the book covers rheology and viscosity. High temperature is also discussed as it can lead to poor quality mouldings due to material degradation
Interfacial instabilities: implications for multi-material moulding
Get PDFThis work investigates and identifies the mechanisms that are at work in the creation of instabilities during co-injection moulding. Two aspects are investigated, neither of which has been previously reported. One seeks to eliminate the instabilities, the other to control them to produce mechanical interlocking of incompatible polymeric materials. Complex rheological and thermodynamic interactions take place during the co-injection moulding of materials of different generic families, which need to be understood before successful multi material mouldings can be achieved. Moulding trials on miscible, compatibilised and immiscible polymer systems were carried out to determine processing parameter effects.
Analysis of tensile behaviour identified differences between injection moulding and co-injection moulding samples which are indicative of different heating and cooling regimes in the systems. Scanning electron microscopy analysis also assisted explanation of these effects. A previously unobserved bulk weakness in compatibilised systems was found. Surface profilometry was used to measure the size of disturbances at the wave fronts. The extent to which the interfacial instability occurs and to the material systems to which it applies was found. Instabilities were found or induced in all material systems investigated, including those where skin and core materials are the same. Mechanisms of instability at the melt front interface were determined and were found to be the result of stratification of elastic properties. Processing conditions were found to minimize instability by minimizing differences in elasticity at the interface. A novel process route using controlled instabilities was also proposed and investigated for the use of immiscible material systems. By controlling the moulding parameters, the potential problem of instability was used to provide a solution to bonding immiscible materials in co-injection mouldings without the use of compatibiliser
Recycling of elastomer and polymer matrix composites
No full textWaste disposal strategy for composites is dominated by the so called four “R”s: reduce, reuse, recycle, recover. For polymer and elastomeric matrix composites this process is complicated by the mixed nature of the constituent parts and their subsequent economic viability. Therefore, this article outlines the various process options and major issues in reuse, recycling and recovery of these materials. As composite materials have become increasingly widespread due to their advantages, commercially viable recycling and recovery solutions are yet to be satisfactorily defined for all materials streams. For this reason this article will consider major themes in relation to the reprocessing distinction between thermoset and thermoplastic matrix materials and the impact of various components on the subsequent recovery efforts. It will also cover processes for recycling and recovery. The design concepts of ‘reduce’ are also covered as part of more holistic design possibilities and future prospects and conclusions are presented in the drive towards the circular economy
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