Phase Behavior and Morphological Studies of Polyimide/PVP/Solvent/Water Systems by Plase Inversion

摘要

The solubility gaps for poly(vinyl pryyolidone) (PVP) in four polyimide solution (NMP, DMF, GBL, DMSO) were determined by cloud point measurement and correlated with X_PI/Solvent and #DELTA##delta#_PVP/Solvent. Membranes prepared with NMR and DMF systems showed a tendency of suppressing fingerlike structure with addition of PVP. On the other hand, membranes prepared with GBL and DMSO systems showed an inclination toward inducing macrovoid formation. These effects of PVP on the membrane morphology were explained by means of miscibility gap, viscosity of the polymer solution, polymer-phase separation, and overall porosity.