Recycling of Some Polymers Used in Building

For low density, flexible high resilient and rigid PU foam post-consumer wastes, a modified solid state shear extrusion (SSSE) technique was applied for their pulverisation. The fine powder obtained can be nsed as a filler and/or reinforcing material for polymers and mineral products with improved mechanical properties [257]. 

As for the major PVC flows, several recycling schemes mainly based on mechanical recycling have been and will be set up, particularly in the northern EU countries (notably Scandinavia, Germany, Austria and the Netherlands). These schemes rely on covenants between the authorities and the PVC industry, or voluntary incentives of the PVC industry. The potential of PVC waste (pure resin) for chemical recycling in ktons in the period 2000-2010 is given in Table 7.8 [258]. 

Reprinted with permission of TNO Strategy, Technology and Policy, The Netherlands, from TNO report STB-99-55, page 69.  

For collecting purposes with a view to recycling of PVC waste, it is recommended that a single material is used, for example window profiles [260-263]. Complete PVC window frames are made of 38% PVC, 34% glass, 24% metal, 4% other materials. Such a frame contains 18 kg PVC [264]. 

The mechanical properties of recycled PVC are detrimentally affected by the presence of contaminants which act as stress concentrators and so cause premature failure upon loading. Pulverisation of the recyclate to reduce the size of such impurities results in improved properties that compare with those of pure grades. Often contaminants can be other polymers such as PET, PE, paper, and so on [265]. In many countries especially European countries, PVC windows are now the first choice, ahead of those made from conventional materials and recycling is increasing to meet this demand. Thanks to their life span of up to 40 years without necessary maintenance, the qualities of these window frames currently entering the waste stream are modest. This will increase over time as more are used and as the windows, which were installed in the sixties, enter the waste stream. Germany already has automated plants for recycling PVC window frames. 

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