Green Fabrication\nof Biobased and Degradable Poly(lactic\nacid)/Poly(butylene succinate) Open-Cell Foams for Highly Efficient\nOil–Water Separation with Ultrafast Degradation

Biobased poly(lactic acid) (PLA)/poly(butylene\nsuccinate)\n(PBS)\nfoams with excellent oil–water separation capability were fabricated\nusing supercritical fluid foaming. PBS acts as the cell-opener and\nnucleating agent, and the introduction of a chain extender (a multifunctional\nepoxide oligomer, Joncryl ADR-4468, ADR) enhances the compatibility\nbetween PLA and PBS and improves the rheological properties of PLA/PBS.\nPLA with 6 wt % PBS (PLA/PBS6) exhibits a high expansion ratio of\n52 and an open cell content of 97.9%. It is notable that different\ncell structures of varying sizes show significant differences in the\nadsorption capacity and rate. Compared to PLA/PBS9 foam with a similar\nexpansion ratio and open-cell content, the adsorption capacity of\nPLA/PBS6 has increased from 18.8 to 24.5 g/g, but the adsorption rate\nconstant decreased. Smaller cells are more effective at increasing\nthe adsorption capacity, while larger ones are beneficial in reducing\nthe saturation time. PLA/PBS6 foam shows a contact angle of 139°\nwith deionized water, oil adsorption capacities ranging from 24.5\nto 50.7 g/g, and retains 84.3% of its CCl<sub>4</sub> adsorption capacity\nafter 10 cycles. PLA/PBS6 foam degrades over 90% in 5 days in alkaline\nenvironments (pH = 13). The work provides a novel strategy for the\ngreen fabrication of ultralight foams with outstanding oil–water\nseparation properties. It is expected to meet the requirements of\ndifferent oil–water separation situations by regulating the\ncell structure and size distribution via controlling the adsorption\ncapacity and adsorption rate.