A new strategy to simultaneously improve the permeability, heat-deformation resistance and antifouling properties of polylactide membrane via bio-based β-cyclodextrin and surface crosslinking

The permeability and thermal stability are crucial to the application of environmentally benign, sustainable and bio-based polylactide (PLA) membrane. In the present work, we introduce a bio-based pore forming agent β-cyclodextrin to enhance the permeability of PLA membrane. Furthermore, we improve the protein resistance and heat-deformation resistance via a surface crosslinking strategy. P(VP-VTES) copolymer was first synthesized and seeded on the surface of PLA membranes steadily through the swelling, hydrolysis and condensation. The physicochemical property of PLA membrane was characterized by XPS , FTIR and SEM. The hydrophilicity, pure water flux and BSA fouling resistance were evaluated respectively. The crystallization evolution of PLA membrane was investigated by DSC and XRD . It was found that the surface crosslinked P(VP-VTES) significantly improved the hydrophilicity, dry membrane flux recovery (~98%) and BSA resistance. Meanwhile, the surface crosslinking induced the crystallization of PLA membrane up to ~38% degree of crystallinity and withstood ~100   °C hydrothermal treatment without dimension deformation or filtration performance deterioration. This study suggests a simple but effective strategy to simultaneously enhance the fouling resistance and thermal stability, as well as the permeability of PLA membranes through the surface crosslinking and the pore forming agent β-cyclodextrin.