Recycling plastics from waste computer equipment

In light of recent European legislation, an increase in recycling and recovery activities is required in the electrical and electronic sector in order to meet stipulated targets. For waste plastics this also includes the separation of plastics containing brominated flame retardants from those that do not. Studies into the FTIR (Fourier transform infrared) spectra of a collection of plastics from waste housings for computer equipment and comparisons with spectra from a selection of flame retardants, as well as testing different plastics identification systems have concluded that infrared spectroscopy cannot be used to detect flame retardants in plastics in the current state of technology. However flame retardants may be detected by using a combination of identification techniques such as IR (infrared) for plastic identification and pyrolytic spectroscopy for additive detection. The effects of recycling and blending on a commercial scale have been assessed on mechanical properties of the four most used plastics in computer equipment housings. Recycled ABS (acrylonitrile-butadiene-styrene), HIPS (high impact polystyrene), modified PPO (polyphenylene oxide) and PC (polycarbonate) /ABS alloy were tested in the pure form and as various blends of ABS and HIPS, HIPS and modified PPO (mPPO), ABS with PC/ABS and a blend of all four plastics. Properties tested were tensile and impact properties, DMT A (dynamic mechanical thermal analysis), viscosity, molecular weight and surface and bulk microscopy. Generally changes to mechanical properties following recycling of pure ABS, HIPS, PPO and PC/ABS are quite small, although there are slight reductions in ductility for HIPS and mPPO. All plastics used in this study appear unaffected by the presence of a small proportion of another plastic, although at higher blend proportions impact strengths of ABS/PC/ABS deteriorate, properties of ABS/HIPS blends remain unaffected and larger proportions of HIPS/PPO are beneficial to all properties. These results indicate that a plastics identification system probably does not need to be exactly 100% accurate.