Supercritical CO2 Extrusion Foaming of Highly Open-Cell Poly(lactic Acid) Foam with Superior Oil Adsorption Performance.

Addressing marine oil spills and industrial water pollution necessitates the development of eco-efficient oilabsorbing materials. With increasing concern for the environment, there is a consensus to decrease the use of petroleum -based polymers. Herein, lightweight poly(lactic acid) (PLA) blend foams with varying thermoplastic polyurethane (TPU) content were fabricated via a solvent -free, eco-friendly supercritical carbon dioxide (scCO 2 ) extrusion foaming technology. The incorporation of TPU significantly enhanced the crystallization rate of PLA, with the semi -crystallization time of PT30 and PT50 blends at 105 degrees C exhibiting a reduction of 77.2 % and 47.9 %, respectively, compared to neat PLA. The resulting foams exhibited an open -cell structure with excellent selective oil adsorption capabilities. Notably, the PT30 foam achieved a remarkable maximum expansion ratio of 36.0, while the PT50 foam attained the highest open -cell content of 96.2 %. The PT50 foam demonstrated an outstanding adsorption capacity, spanning from 4.7 to 18.8 g/g for diverse oils and solvents, with rapid adsorption kinetics, reaching 94.9 % of the equilibrium adsorption capacity for CCl 4 within just 1 min. Furthermore, the PT50 foam retained 95.2 % of its adsorption capacity for CCl 4 over 10 adsorption -desorption cycles. This study presents a scalable and sustainable approach for large-scale production of high-performance, bio-based foams, facilitating efficient oil -water separation.