Plastic packaging typically consists
of a mixture of polymers and
contains a whole range of components, such as paper, organic residue,
halogens, and metals, which pose problems during recycling. Nevertheless,
until today, limited detailed data are available on the full polymer
composition of plastic packaging waste taking into account the separable
packaging parts present in a certain waste stream, nor on their quantitative
levels of (elemental) impurities. This paper therefore presents an
unprecedented in-depth analysis of the polymer and elemental composition,
including C, H, N, S, O, metals, and halogens, of commonly generated
plastic packaging waste streams in European sorting facilities. Various
analytical techniques are applied, including Fourier transform infrared
(FTIR) spectroscopy, differential scanning calorimetry (DSC), polarized
optical microscopy, ion chromatography, and inductively coupled plasma
optical emission spectrometry (ICP-OES), on more than 100 different
plastic packaging products, which are all separated into their different
packaging subcomponents (e.g., a bottle into the bottle itself, the
cap, and the label). Our results show that certain waste streams consist
of mixtures of up to nine different polymers and contain various elements
of the periodic table, in particular metals such as Ca, Al, Na, Zn,
and Fe and halogens like Cl and F, occurring in concentrations between
1 and 3000 ppm. As discussed in the paper, both polymer and elemental
impurities impede in many cases closed-loop recycling and require
advanced pretreatment steps, increasing the overall recycling cost.
