A preliminary study of flat sheet asymmetric membrane formation for gas separation applications

Abstract

The common technique for the preparation of polymeric membranes with asymmetric structure is the phase inversion process. In this process, a polymer is dissolved in an appropriate solvent before casted on a suitable support. The casted film is then immersed in a non-solvent bath and the coagulation process taking place to form a membrane. The asymmetric membrane structure and its properties are influence by many experimental parameters such as the thickness of membrane, the polymer solution composition, coagulation bath composition, choice of solvent and non-solvent, the membrane casting speed and the knife shape which inducing casting shear rate can be determined in the membrane casting procedure. In order to produce a good quality flat sheet asymmetric membrane, a unique pneumatically-controlled flat sheet membrane casting system were designed and fabricated in this study. The present study seeks to optimize those parameters suitable for membrane making, which will exhibits good separation performance in gas separation application. To achieve the above objective, a few framework have been drawn such as optimizing the initial membrane solution formulation, characterizing the thermodynamic and rheological properties of the polymer solution. The orientation of the polymer molecules is also important in membrane making and will also investigated in order to enhance membrane selectivity.