Ultrahigh molecular weight polyethylene (UHMWPE) fibers are high-performance materials typically obtained via gel spinning, a technique that requires extensive use of organic solvents to wash the produced fibers, posing significant environmental concerns. This study presents a novel washing method employing supercritical carbon dioxide (scCO2) and evaluates its environmental sustainability using life cycle assessment, across 17 midpoint indicators. The new scCO2-based process (scCO2W) enables the recovery and reuse of CO2 and residual mineral oil from gel spinning. Comparative results indicated that scCO2W outperforms conventional hexane-based washing (HW) in 13 categories, including a 2.4-fold reduction in the global warming potential (GWP). Energy consumption for fiber washing was identified as the main hotspot in scCO2W, and a sensitivity analysis indicated that switching to renewable electricity sources can lead to a 45% reduction to the estimated GWP. Scenario analysis of alternative solvents showed that hexane performed better than heptane and dichloromethane in most indicators. Evaluation of two end-of-life scenarios for HW showed that incineration with energy recovery is generally more beneficial than solvent recovery; however, the recovery option showed advantages in GWP reduction with up to 33% lower impact. Finally, scenario analysis of the scCO2W process highlighted the critical role of CO2 and mineral oil recovery, suggesting that benefits of scCO2W are only evident when recovery is ensured. The findings support the adoption of scCO2W as a more environmentally sustainable alternative for cleaning UHMWPE fibers with the potential to transform the footprint of current manufacturing processes.
Guzmán et al. (Sat,) studied this question.