(336c) Development of Membrane Morphology in Relation to Phase Diagrams of Amorphous Polyamide/Polyvinylpyrrolidone Blends Containing a Phytochemical

Miscibility behavior of an amorphous polymer blend containing a crystalline 'phytochemical' was studied in relation to membrane formation via non-solvent induced phase separation. Dimethylsulfoxide (DMSO) and water were predominantly used as solvent and non-solvent, respectively. Factors influencing membrane morphology of the membranes were analyzed. Differential scanning calorimetry and optical microscope results revealed that the binary PA/PVP blends were completely miscible at all compositions. However, binary blends of PA/phytochemical and PVP/phytochemical showed a solubility limit of phytochemical in the polymer matrix. Cloud point measurements were carried for PA-PVP/DMSO/Water system (unmodified membrane) to establish the immiscibility gap. The addition of phytochemical to the membrane forming system (modified membrane) increased the area of immiscibility. SEM and AFM micrographs showed the presence of finger-like/sponge-like morphologies in the membrane cross-section, whereas dense/porous morphologies at the skin layer. The effects of casting parameters such as polymer concentration, PA/PVP blend ratio, solvent, humidity and concentration on the membrane morphology were investigated.