Plastic waste homogeneous

Mechanical recycling is the preferred route for homogeneous and relatively clean plastics waste streams. It is assumed that the cushion vinyl floor covering will be mechanically recycled [11].1... 

Ideally we would like to reuse plastic waste to form directly new plastic products, but mechanical reprocessing of used plastics into new products has so far limited application. It is restricted to the treatment of relatively pure and well-defined waste, mainly from polymer processing factories. Mechanical reprocessing of municipal plastic waste results in new products of quality inferior to their virgin plastic ones. Separation of waste to streams of the same polymer type on the other hand is still very expensive. This fact restricts the applicability of mechanical reprocessing in polymer waste that is homogeneous in type and properties. 

The heterogeneous commingled plastics waste is converted into a homogeneous liquid or granulated at the exit of the extruder or heated up so much at the end of the extruder... 

Progress in plastic separation and sorting is a key factor in the future development of both mechanical and feedstock recycling. As methods of plastic sorting are improved, the purity and homogeneity of the plastic wastes is increased, which favours the application of more advanced degradation... 

In the same line of recycling plastic waste without the aid of compatibilizers, the family of homogenization and sohd-state pulverization processes can be found (Daren 1998 DubmUe D Orhcel 1993 La Mantia et al. 1996 Khait et al. 1999 Khait et al. 2001) essentially based on the fractionation of plastic waste into fine particles and formation of cross-polymers induced by shear activated reactions that... 

However, in order to expand the recovery and recycling of plastics and decrease the amount of waste disposed in landfills, it will be necessary to overcome these difficulties. Because of its heterogeneous nature and the amount of contaminants present, separation of post-consumer mixed plastic waste is the most difficult. Waste plastics from industrial operations are cleaner and more homogeneous in resin type and scrap form than postconsumer plastics. The term "mixed plastics" has been used to describe broad scale processing of post-consumer plastic waste, although no formal definition yet exists. In its broadest sense, mixed plastics means a collection of a mixture of plastic resins or a mixture... 

La Mantia, F.P. (1996) Basic concepts on the recycling of homogeneous and heterogeneous plastics, in F.P. La Mantia (ed), Recycling of PVC Mixed Plastic Waste, ChemTec Publisher, Toronto, pp. 63-76. 

When mixed plastics waste is processed, one of the main problems is to find the best compromise between homogenization and degradation. In the waste material, there are polymers with different melting points and different thermal stability. Especially, PVC and PET are very difficult to process together, because the melting point of PET is over 250°C, and at this temperature PVC is easily decomposed forming HCl and chary residues. Therefore, the optimal processing... 

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