Polymers energy recovery from

Recycling of polymer materials is also increasingly desirable due to the overall environmental and social benefits, particularly for plastics from post-consumer waste. Energy recovery from plastic waste and the biodegradation of packaging materials are other areas of recent development. 

Materials and energy recovery from polymer wastes by pyrolysis and combustion. 

Energy recovery from waste by incineration is a very controversial issue. It has a low degree of acceptance due to environmental pollution and corrosion problems. Polymer wastes, particularly polyolefin ones, have a high calorific value of 36-46 MJ/kg. Hence they will give an important contribution to reducing the energetic needs in the production of hot water, steam, electricity, etc. 

The last quadrant in Figure 16 shows the areas for eventual product diversification from energy and/or liquid biofuel vectors. Although these do not appear to offer great market potential they can address niche markets for the production of bio-chemicals and/or the recovery of the valuable products such as the monomer from waste polymers and aluminium from drink packaging. 

Since the plastics are produced from petrochemicals derived from hydrocarbons, the motivation to reuse, recycle, or reprocess for energy recovery is primarily driven by an interest in conservation of petroleum resources. Economic factors are also important, but the potential saving of landfill space is more a perception rather than a reality [9]. Most of the categories of vinylic polymers discussed in this chapter are melt-formable, that is, they are thermoplastic materials, rather than nonmelting or thermosetting as are several of the condensation polymers discussed in Chapters 20 and 21. Thus,... 

Beside the raw material supply and the fermentation process itself, downstream processing for polymer recovery from the surrounding cells is another cost-determining factor in biopolymer production. Especially for this process step, additional research progress is required in order to decrease the demands for energy and chemicals that severely antagonize the sustainability of PHA production. 

As seen in Fig. 4.2 and 4.3, in particular, polymer B with DBDI hard segments, showed higher stiffness and strength than the conventional MDI-based polymer A, but with lower strain recovery and strain energy recovery on cycling—a primary consideration for elastomers. Both features of the response were attributed to differences in hard phase plastic flow stress, resulting from crystallinity in the DBDI phase [60, 61,127,135], absent in MDI. 

Compatibilisers are certain to benefit from the recycling trend, but the reuse of polymers for plasties (as opposed to their use as fuel or their conversion to feedstock for chemical intermediates) may be aeeompanied by the reuse of at least a proportion of the additives. Researeh is being earned out to make possible the systematic recovery of additives from used artieles. Several observers believe that energy recovery and feedstock recycling will often be more eeonomie than eonversion to second-life plastics products. 

M. Xanthos and A.L. Bisio, "Energy Savings from Plastics Recovery Technologies", The Intersociety Polymer Conference, Baltimore, MD, October 7-10, 1995. 

Many fields of expertise are necessary for the understanding of problems involved in the value recovery from plastics waste, either as materials, chemicals or energy. For these reasons contributions are required from chemists, physicists, engineers as well as polymer and materials scientists. Due to the dimension of the subject, the participation of the environmental, legal and economic experts is also of paramount importance. 

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