Thermoplastic elastomer melt-blown fiber mats for oil spill remediation: Fabrication, oil uptake, and gel formation studies

Melt-blown fibers, featuring porous structures with designed wetting characteristics can provide superior oil/water separation performance. The core objective of this work was to design a material that provides excellent oil/water selectivity for oil spill remediation. For this, the selective oil gelation properties of styrene-ethylene-butylene-styrene (SEBS) and the enhanced surface area provided by melt-blown mats was leveraged to achieve exceptional oil/water selectivity. Nonwoven mats based on SEBS were fabricated with a twin-screw extruder equipped with a custom-engineered melt-blowing die. To address the inherent low melt flow index (MFI) of SEBS, which presents challenges in the melt-blowing process due to decreased stretchability, high MFI polypropylene (PP) was incorporated as a blending additive. Next, the impact of blending polypropylene with SEBS on melt-blowing processability and fiber quality was studied. The inclusion of 10 wt.% PP in SEBS considerably enhanced fiber melt-blowing processability, resulting in a more extensive and evenly spread fiber stream. Further analysis of this fiber composition in terms of oil and water interaction revealed superior oil uptake capacity. Moreover, the increased surface area of SEBS-based fibers enhanced their interaction with oil, resulting in the effective formation of a semi-solid gel. Notably, the generated gel established a barrier that successfully limited further oil dispersion even when the material reached its saturation point. This demonstrated a markedly superior oil immobilizing performance in comparison to polypropylene melt-blown fibers.