FT-IR analysis and hyperspectral imaging applied to post-consumer plastics packaging characterization and sorting

Abstract—Post-consumer plastics packaging waste represents one of the primary source of recovered polymers. One of the main problem now arising is thus the need to certify, in a fast (i.e. “on-line”) and reliable way, recovered plastics composition, as well as to assess polymers mixtures bulk characteristics, in order to partially, or totally, re-use them. The study is addressed to verify the possibility offered by a new technique, HyperSpectral Imaging (HSI) based, in order to perform a real time “on-line” identification of polymers as resulting from a recycling process. This approach was specifically adopted to identify the presence of PolyVinyl Chloride (PVC) in the heavy fraction resulting from an industrial sink-float process. PVC detection is important because heavy fraction recovery is finalized to its further re-utilization as Solid Recovered Fuels (SRF). The presence of this polymer, in fact, for its chlorine content (i.e. dioxin production during combustion) negatively affects the thermal recovery of these products. The study demonstrated as the proposed HSI based approach, in the NIR range (1000-1700 nm), can be successfully utilized to set up “real time” analytical/control strategies to perform a continuous monitoring of the composition of the different flow plastic waste streams resulting from industrial processing, with particular reference to PVC identification.