Life Cycle Assessment of Chemical Recycling of Polyethylene Terephthalate to Produce Aramid Polymers

With the growing demand for plastics production, there is a need to reduce petroleum dependence and shift toward a more circular economy to mitigate damages on the environment. While there are multiple end-of-life management pathways for plastics, chemical recycling is a key method that could support the recycling of plastics without deterioration of material properties. In this work, we implement a life cycle assessment methodology to assess 12 chemical recycling pathways that facilitate the conversion of polyethylene terephthalate (PET) to a Kevlar-like material (including aramids and polyphthalamides) using aminolysis. We compare various environmental impacts, focusing on pathways that could limit greenhouse gas (GHG) emissions. Results showed that 8 of the 12 scenarios resulted in lower GHGs than conventional virgin Kevlar production, with impacts being driven by the energy demands and solvents used. Of those studied, our results indicate that hexamethylene diamine provides the lowest impacts as a chemical solvent. Higher impacts were commonly linked to low-yield pathways suggesting that chemical recycling methods will need to balance inputs, driving toward low energy, low-impact solvents, and high polymer yield.