Effects of Organic Additives on the Relationship Among PAN Casting Solution, Gelation Dynamics and Membrane Performances

Abstract

This paper demonstrates the effects of organic additives including PEG400 (polyethylene glycol 400), OA (oxalic acid), PEG4000 (polyethylene glycol 4000), and PEO-PPO-PEO (polyethylene oxide-polypropylene oxide-polyethylene oxide) adopted the liquid-solid phase inversion approach on casting solution, gelation dynamics process and polyacrylonitrile (PAN) membrane performances, furthermore, the relationship among them is analyzed. The four additives enlarged the casting solution viscosity, in which OA and PEO-PPO-PEO accelerated the gelation velocity. Rejections of membranes were all improved above 80.0%, furthermore, OA, PEG400, and PEO-PPO-PEO also enhanced the water flux of the membrane. All membranes prepared were shown with unbalanced finger-like surface structures. The gelation velocity and water flux changing trends with OA and PEG4000 were similar. The rules of the relationship among membrane performance, gelation process, and casting solution viscosity varied among different additives.