Laser-induced plasma spectroscopy for plastic identification

The goal of this work was instant identification of post-consumer plastics by laser induced plasma spectrometry (LIPS). LIP spectra from plastics in a 200-800 nm spectral window were compared with reference spectral libraries stored in a computer. The libraries consisted of representative spectra fr om different groups of recycled plastic samples. The plasma emission spectr a of polyethylene terephthalate (PET), high density polyethylene (HDPE), po lyvinyl chloride (PVC), low density polyethylene (LDPE), polypropylene (PP) and polystyrene (PS) were studied. Simple statistical correlation methods including linear and rank correlations were used. The probabilities of corr ect identification ranged from 0.8 to 1 with values close to unity for most of the polymers studied.