Development and theoretical analyses of polymeric membranes and mixed matrix membranes for gas separation

Abstract

Polymeric membranes play a vital role in many industrial separation processes. A considerable amount of work is presently in progress to improve the performance of polymeric membranes for gas separation. Many research efforts are devoted to the development of membranes that exhibit both high selectivities and permeabilities to specific gases. In this thesis, motivated by the idea that the combinations of polymer matrices and inorganic fillers could obtain the desirable properties of the individual components and probably achieve better separation performance in terms of high permeabilities and selectivities, the work focused mainly on the study of organic-inorganic mixed matrix membranes (MMMs). A comprehensive study on the effects of membrane thickness and heat treatment, the selection of inorganic fillers and the preparation methods, on the properties of the resulting membranes, is presented. Various instruments such as TGA (thermogravimetric analysis), DSC (differential scanning calorimetry), XRD (X-ray diffraction), SEM (scanning electron microscope) and TEM (transmission electron microscope) were used to characterize the membranes. The main objective of this research programme was to determine the relationship between the membrane structures and the gas separation performance. Besides the mixed matrix membranes, it was also desirable to study asymmetric membranes, researching into the effects of the preparation conditions on the separation properties of the resulting asymmetric membranes.