Life cycle assessment of mechanical recycling of low-density polyethylene into film products - towards the need for life cycle thinking in product design

In this study, we conducted LCA on the environmental impacts of recycling LDPE films within two system boundaries. System boundary 1 analysed the operations of a recycling company producing recycled LDPE granules. The results were comparable to the literature, yielding 0.44 kg CO2-eq./kg LDPE. Polymer testing revealed that recycled LDPE foil products had a higher mass per product than virgin materials to compensate for inferior material properties. System boundary 2 was modelled to analyse existing film products, incorporating both recycled and virgin LDPE and using data from system boundary 1, to fulfil the same function. Due to the incineration at the products' end of life, some recycled products showed higher climate change footprint, due to the additional mass. Accordingly, the idea of a threshold called the environmental break-even was introduced, indicating the maximum surplus of low-quality recyclate usable to achieve the same climate change impact than a purely virgin competitor.