aData for Hong Kong has been separately compiled although it is a part of China. b 1997 data. Table was compiled from data in reference [1].

aData for Hong Kong has been separately compiled although it is a part of China. b 1997 data. Table was compiled from data in reference [1].

4 Recent admission of China into the World Trade Organization (WTO) can also favor the processing industry as the import tariffs on advanced equipment are gradually reduced and export subsidies the industry operates under are removed.

Asian countries; the data is approximate [1] but adequate to yield some idea of the magnitude of the industry.

A comprehensive introduction to common polymers and their manufacture within a single chapter is impractical and is not the present objective. It is only those plastics that are used in high enough volume in common applications that interact significantly and visibly with the environment. This is particularly true of solid-waste related issues where attention has often focused on polystyrene foam and polyolefin packaging materials. Also, the magnitude of environmental impacts generally increases with the worldwide production volume of a material (although the intensity of such impacts may change with individual materials in question). Therefore, this chapter is limited to a discussion of the common thermoplastic materials that are produced in large volume and therefore of particular environmental significance. The treatment is intended to introduce the reader to the manufacture and general uses of these plastics. For the present purpose "common" plastics include the high-volume commodity resins polyethylene, polypropylene, poly(vinyl chloride), polystyrene, and thermoplastic polyester. Also included in the discussion are polymeric foams that are a visible and environmentally interesting group of products because of their link to the use of chemicals that are stratospheric ozone-depleting substances (ODS). The five most commonly used thermoplastics in the U.S. and their consumption levels are shown in Table 2.2.

A fundamental question on plastic materials is their true cost in terms of nonrenewable resource use and energy use, as well as the emission loads associated with their manufacture. This will be discussed in detail in Chapter 3. The energy estimates shown in Table 2.3 were taken from a recent U.S. study carried out by Franklin Associates for the Society of Plastics Industry [2, 3]. The total energy per 1000 lb of plastic products includes the energy content of raw materials (petroleum and natural gas resources), the energy used in manufacture of the resin, processing energy used to fabricate the product, as well as the associated transportation energy. The margin of error in the estimates is about 10%. Plastics compare well with competing materials such as glass, metal, and wood

Table 2.2 U.S. Resin Production in 2000 and Change from Previous Year

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