Plastics Brief

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Resilient materials such as rubber and some plastics may be useful in certain applications, especially under conditions of low cavitation intensities. However, such materials are subject to disbondment at the metal and elastomer interface at high cavitation intensities, even if the exposure is brief. 

After a brief historical review in Chapter 1 the following five chapters provide a short summary of the general methods of preparation of plastics materials and follow on by showing how properties are related to chemical structure. These particular chapters are largely qualitative in nature and are aimed not so much at the theoretical physical chemist but rather at the polymer technologist and the organic chemist who will require this knowledge in the practice of polymer and compound formulation. 

In this book no prior knowledge of plastics is assumed. Chapter 1 provides a brief introduction to the structure of plastics and it provides an insight to the way in which their unique structure affects their performance. There is a resume of the main types of plastics which are available. Chapter 2 deals with the mechanical properties of unreinforced and reinforced plastics under the general heading of deformation. The time dependent behaviour of the materials is introduced and simple design procedures are illustrated. Chapter 3 continues the discussion on properties but concentrates on fracture as caused by creep, fatigue and impact. The concepts of fracture mechanics are also introduced for reinforced and unreinforced plastics. 

This chapter discusses synthetic polymers based primarily on monomers produced from petroleum chemicals. The first section covers the synthesis of thermoplastics and engineering resins. The second part reviews thermosetting plastics and their uses. The third part discusses the chemistry of synthetic rubbers, including a brief review on thermoplastic elastomers, which are generally not used for tire production but to make other rubber products. The last section addresses synthetic fibers. 

In the following sections, a brief account of general laboratory apparatus relevant to quantitative analysis will be given. The commonest materials of construction of such apparatus are glass, porcelain, fused silica, and various plastics the merits and disadvantages of these are considered below. 

Failure can be considered as an actual rupture (stress-rupture) or an excessive creep deformation. Correlation of stress relaxation and creep data has been covered as well as a brief treatment of the equivalent elastic problem. The method of the equivalent elastic problem is of major assistance to designers of plastic products since, by knowing the elastic solution to a problem, the viscoelastic solution can be readily deduced by simply replacing elastic physical constants with viscoelastic constants. 

The remainder of this chapter provides a summary overview on plastic materials. This section reviews different types of plastics. The descriptions are brief listing a few of their main characteristics. Details cannot be included since so many different formulations... 

In the following list of materials brief explanations of performances and limited applications are given for a few of the different plastics. What is presented will provide some degree of familiarity with the variations of properties existing in the different plastics. Throughout this book many different properties are reviewed. The order in which the following descriptions of plastics are arranged... 

With all types of plastic processes, troubleshooting guides are set up to take fast, corrective action when products do not meet their performance requirements. This problem-solving approach fits into the overall fabricating-design interface. One brief example of troubleshooting an RP/composite is in Table 8-44. 

Thompson, J. K., Driving Plastics Use in Auto Design, NASA Tech Briefs, Sep. 1999. 

From this brief discussion it is clear that crosslinking in phenol-formaldehyde resins is complicated and no individual specimen of these materials can be characterised well at the molecular level. Crosslinking is irregular and variable, though it gives rise to a material having sufficiently acceptable properties that it became the first commercially important plastic material indeed, as mentioned in Chapter 1, these resins continue to retain some commercial importance in certain specialised applications. 

This reports on the developments by a German company in the use of gasification in the chemical recycling of plastics waste. Brief details are given. 

This provides brief information from a new report, produced on behalf of the British Plastics Federation, by the Centre for Economics Business Research, which says that over half of the UK s EPS packaging will be reclaimed by the year 2010, using recycling or waste-to-energy schemes. 

This article provides brief information from a study carried out in the Netherlands, which revealed that combustion with energy recovery is the most economical way of processing waste plastics, whilst mechanical recycling is the most environmentally attractive option. 

Thermal recycling of plastics is becoming a more popular option in Japan, largely because of a lack of landfill sites, and also because of the materials potential as an untapped source of energy. The article supplies brief details of the advantages of thermal recycling. 

Current methods of feedstock recovery are reviewed. Brief details are given of pyrolysis, hydrogenation, gasification, and chemolysis. Activities of some European companies are briefly discussed in the areas of recycling mixed plastics waste and closed-loop recycling. 

Brief details are given of two proposed resolutions on the subject of pyrolysis of waste plastic. The first states that pyrolysis and other methods of chemically reprocessing post-consumer plastics is a suitable way of diverting waste from landfills. The second resolution, supported by environmentalists, states that pyrolysis only recovers plastic s energy value, and should not be viewed as recycling. 

Position 5 in Fig. lb describes the brief explosive development of biomass in an ephemeral species capable of exploiting a productive but temporary habitat. Here again morphological plasticity would be expected to predominate. In the vegetative phase, plasticity in root and shoot morphology will be an integral part of the mechanism of resource capture. 

Polyurethanes, as a class of materials, are one of the most versatile available. By varying the reactants, their amounts and the reaction conditions, one can obtain millable elastomeric gums, hard rigid plastics, reactive liquids, and foams. The versatility is such that it is very difficult to provide a brief summary. 

The background to the forthcoming harmonisation of standards and testing procedures for plastics in contact with water is outlined and a brief discussion is presented on the expected unified tests, the synoptic documents in which raw materials, which pass these tests, will be included and the process optimisation carried out by Ticona to conform to the new requirements. (Kunststoffe, 92, No.2, 2002, p.77-9)... 

The use is examined of plastics in medical applications with reference to the US market for additives for these products. The use of plastics for medical applications, which include products and components of equipment, and packaging, is expected to exceed 4 billion US dollars in the next two years, with perhaps double or treble that figure for the world market, it is forecasted. The regulatory bodies governing the use of additives are reviewed, and specific additives discussed include plasticisers, stabilisers, conductive additives, and lubricants. The production of compounds for use in the medical sector is examined with reference to the activities of leading companies, and brief details of product developments are included. 

It is announced in this short article that the European Commission has voted for no further restrictions on the marketing and utilisation of cadmium pigments to colour plastics, thereby halting the trend of recent years in reducing the number of applications in which these pigments are permitted. Brief details are provided. EUROPEAN COMMISSION... 

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