Up/down frunk: comparing recycling methods for non-woven poly(ethylene terephthalate) from an electric vehicle

When assessing optimal recycling routes for a specific plastic product, the object geometry and formulation complexity play a significant role. For example, poly(ethylene terephthalate), PET, depolymerization processes that work well on bottles may not apply well to other sectors. Here, we compare the technical feasibility of two recycling methods for a non-woven PET textile from an electric vehicle. We consider thermomechanical recycling through shredding and re-extruding to produce a new filament, as well as chemical recycling by glycolysis. The success of each technique and the scale up thereof is compared, along with the need for pretreatment. Thermomechanical recycling proved challenging, as the material did not feed consistently into the extruder, resulting in an inconsistent and degraded filament. Glycolysis was successful, and indeed faster than when utilizing bottle feedstocks, and could be readily scaled to 1 kg of material. Therefore, for a non-woven PET with a carbon black colorant, glycolysis performed better than mechanical processing, highlighting the need to consider object-level technical feasibility alongside sustainability when proposing recycling methods.