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

• PLA membrane with high thermal stability was prepared.
• Surface crosslinking induced crystallization was first revealed.
• β-cyclodextrin was used to enhance permeability as a pore forming agent.
• Hydrophilicity and fouling resistance was improved by 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.

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