[...]... Significance of Plastic Materials in Today’s Society 2 Classes of Organic Polymers and their Main Applications Classification of Polymers 3 4 Thermoplastics Thermosets Plastic Additives Rubber Plastic Wastes The Economic and Environmental Impact of Plastic Wastes Management of Plastic Wastes Mechanical Recycling Feedstock Recycling Sorting and Separation of Mixed Plastics Future Trends in Plastic Waste... Impact of Plastic Wastes From an economic point of view, used plastic can be considered as both an important source of valuable chemicals, mainly hydrocarbons, and an energy source The calorific value of most plastics is similar to that of fuel oils and higher than that of coals Plastic wastes can therefore be viewed as potential fuels, when other alternatives of valorization are not possible.' Plastic wastes. .. per year in Japan.8 3 Plastic Wastes The increase in the use of plastic materials in all sectors of industry and in everyday life, as well as the reduction in the lifetime of most plastic products, have led to a continuous increase in the generation of plastic wastes Figure 1.7 illustrates the distribution of solid wastes by sector in Western Europe for 1996 The total volume of waste was 2.6 x lo9... a minimum recycling rate of 15% was established for each individual material There are several reasons for the lack of recycling of plastic wastes, compared to other solid materials such as paper/cardboard and glass A number of problems arise from the large variety of chemical compositions and properties of the different types of plastics, which makes it difficult to establish a general recycling procedure... of used plastic it is necessary to collect about 20000 plastic bottles Because plastic wastes are found in MSW mixed with other solid wastes, complex and costly separation steps are required to produce used plastic streams of relatively high purity Despite all these problems, substitution of plastics by other materials is not environmentally sound According to Gebauer and Hofmann, l 1 replacement of. .. formation of dioxins depends mainly on the incineration conditions rather than on the waste composition On the basis of this hierarchical approach, only non-recyclable and nonenergy valuable wastes should be disposed of in landfills However, the current picture of plastic wastes management is far from this situation Figure 1.10 shows the destiny of plastic wastes in Western Europe during 1996 Most of the plastics... United States Environmental Protection Agency, plastics contribute 28 Yo of all cadmium present in MSW and about 2% of all lead." As a consequence of their low density, plastics cause a greater visual impact on disposal than many other materials Similarly, the light weight of plastics is the origin of important limitations on the recycling of plastic wastes, due to increased collection and transportation... Mechanical Recycling As shown in Figure 1.1 1, mechanical or material recycling of plastics involves a number of treatments and operations: separation of plastics by resin, washing to remove dirt and contaminants, grinding and crushing to reduce the plastic particle size, extrusion by heat and reprocessing into new plastic Because thermosets cannot be remoulded by the effect of heat, this type of recycling. .. on the mechanical recycling of plastic wastes highlight the interest and potential of feedstock recycling, also called chemical or tertiary It is based on the decomposition of polymers by means of heat, chemical agents and catalysts to yield a variety of products ranging from the starting monomers to mixtures of compounds, mainly hydrocarbons, with possible applications as a source of chemicals or fuels... 1996 Approximately 63% of the total plastics waste is disposed of in municipal solid waste (MSW) mixed with a wide variety of other solid wastes There is a relationship between the sector that originates the plastic waste and the life of the plastic products Plastics used in packaging and agriculture generally have a lifetime of less than 1 year, hence in this case the composition of the waste directly . Impact of Management of Plastic Wastes Mechanical Recycling Feedstock Recycling Sorting and Separation of Mixed Plastics Future Trends in Plastic Waste Management 3 Plastic Wastes Plastic. compara- tive study of the various alternatives for the feedstock recycling of plastic wastes. The final conclusion is that feedstock recycling of both plastic and rubber wastes has a high potential. mechanical recycling by melting and regranulation of the used plastics, (ii) feedstock recycling and (iii) energy recovery. Mechanical recycling is limited both by the low purity of the polymeric wastes