Constructing superhydrophobic flame-retardant DBO/PLA fiber mesh for alkane/water separation

The development of biodegradable oil/water separation meshes with flame retardancy is a novel topic at present, carrying substantial implications for the application of biodegradable materials in membrane separation technology, because biodegradable matrix is beneficial to sustainable development and reduces environmental pollution after disposal. In this study, A functional filler (DBO) was synthesized using 3,5-bis(1,1-dimethylethyl)-2-hydroxy-benzaldehyde, 4,4′-diamino- diphenyl sulfone, and 9,10-dihydro-9-oxa-10- phosphate as raw materials via two-step chemical reaction, which has good solubility in various organic solvents. DBO is blended with polylactic acid (PLA) to make electrospun fiber meshes. When the blend ratio of DBO/PLA is 20 wt%, the water contact angle of fiber mesh reaches 150.6 ± 2.4°, while the limited oxygen index (LOI) and UL-94 test are 27.5 % and V-2 level, respectively. The fiber mesh demonstrates selective separation for alkane/water mixture, achieving permeation flux and separation efficiency of 3030 ± 157 L·m −2 ·h −1 and 99.2 ± 0.7 % for n-hexane/water, separately. It exhibits high stability and durability. After several rounds of alkane/water separation, the fiber mesh maintains the flame retardancy as confirmed by ignition tests. Additionally, the tensile strength and elongation at break of the fiber mesh surpassed those of PLA mesh, which are 1.44 ± 0.18 MPa and 54.83 ± 3.66 %, respectively. The integration of flame retardancy with superhydrophobicity into biodegradable polymers will open new avenues for advanced environmental engineering materials.