Development of porous polyketone membrane via liquid-liquid thermally induced phase separation

In recent years, polyketone (PK) porous membranes have attracted significant attention in separation technology owing to its high tolerance to organic solvents. However, its excellent solvent resistance complicates PK membrane preparation procedure, requiring the use of toxic solvents in the conventional nonsolvent induced phase separation (NIPS) method. In this study, the thermally induced phase separation (TIPS) method was explored to prepare porous membranes with PK homopolymer and copolymer. By screening many diluents, we found potential diluents that could be applied to the TIPS method for PK membrane preparation. Two kinds diluent (PEG300 and DPrP) for CPK and one kind pure diluent (PEG200) for HPK were screened to induce L-L phase separation. In the membrane preparation by the liquid-liquid (L-L) phase separation system, the influence of the PK type, cooling conditions, and polymer concentration on the final membrane structure was investigated. Finally, the porous structure, water permeance, and mechanical properties of the membranes prepared using the NIPS and TIPS methods were compared. Prepared CPK and HPK membrane with 25 wt% concentration by TIPS method showed high water permeability (400 and 480 L m(-2)h(-1)bar(-1)) and tensile strength (4.6 and 4.9 MPa). This study will facilitate the development of high-performance PK membranes using the TIPS method, particularly in the selection of diluents.