Life cycle assessment of polyol synthesis from waste cooking oil versus virgin rapeseed oil: Toward sustainable polyurethane foam production

• An LCA of polyol production from waste cooking oil (WCO) was investigated. • Polyol production from virgin rapeseed oil (VRO) was considered as a reference. • The use of WCO was the best option both at midpoint and endpoint level. • The recovery of chemicals can further improve the overall process. • Compared to VRO, the use of WCO can reduce CO2 emissions by up to 42%. Polyurethanes (PU) are lightweight polymeric materials with a broad range of properties and applications, and its market has shown consistent growth. Currently, PU are primarily synthesized from petroleum-derived feedstocks through a polyaddition reaction between isocyanates (R-NCO) and polyols (R-OH). For a sustainable development, the adoption of renewable raw materials and innovative manufacturing processes has become an urgent priority, promoting the replacement of the main fossil-based precursors with bio-based compounds. This study investigated the life cycle environmental impacts generated by the production of 1 ton of polyol from waste cooking oil (WCO) at midpoint and endpoint level. A gate-to-gate approach was adopted, accounting for material and energy use in the following steps: WCO collection, transportation, pretreatment and polyol production via epoxidation and ring-opening reactions. The cultivation and use of virgin rapeseed oil (VRO) as feedstock for bio-polyol production was considered as reference. According to ReCiPe 2016 Midpoint (H), WCO-derived bio-polyol production outperformed the VRO route in 17 out of 18 environmental indicators, reducing CO 2 -equivalent emissions by 15%. Endpoint and sensitivity analyses confirmed the results obtained, highlighting that the combined recovery of chemicals and catalyst used for epoxidation and ring-opening reactions could further increase the environmental benefits in each impact category (e.g., up to 42% reduction in CO 2 -equivalent emissions). The innovative use of WCO in bio-polyol production has proven to be a valid alternative to VRO, improving process sustainability and increasing land availability for agricultural purposes.