Chemical Recycling of Polymers from Waste Electric and Electronic Equipment

This research is focused on the recycling of three types of polymers, namely polycarbonate (PC), poly(acrylonitrile-butadiene-styrene) (PABS), and polystyrene (PS) from Waste Electric and Electronic Equipment (WEEE). Initially, the chemical structure of each polymeric material in a variety of WEEE was identified by Fourier Transform Infra Red (FTIR) spectroscopy and Differential Scanning Calorimetry (DSC). The potential recycling of these polymers from these wastes was examined by employing two different approaches, the dissolution/reprecipitation method and the more challenging technique of pyrolysis. During the first, the polymer is separated and recycled through a solvent/non-solvent system. It is a simple and economic technique leading to high recovery of pure polymer. Both, model polymers and plastic parts from WEEEs were studied and optimum experimental conditions, including dissolution temperature and time, polymer concentration and type of solvent were proposed to achieve significant recovery of the polymer (>90 wt %). Furthermore, pyrolysis of waste Compact Disks (CD) was investigated and compared with model poly(bisphenol A carbonate) (PC) through a laboratory-scale fixed bed reactor. The appropriate pyrolysis temperature was selected after measuring the thermal degradation of model PC by Thermogravimetric analysis (TGA). A large amount of oil was measured, together with a smaller amount of gaseous product, leaving also a solid residue. For both samples, the gaseous fraction consisted mainly Of CO2 and CO whereas in the liquid fraction a large amount of different phenolic compounds, including the monomer bisphenol A, was measured. It seems that recycling of used CDs by pyrolysis is a very promising technique having the potential of producing useful high-value chemicals, which may find applications in the petrochemical industry. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 114: 212-221, 2009