Model studies and preparation of composite gas separation membranes

A resistance model for the transport of gases through composite membranes is proposed . The support membrane used in this paper is a k ind of isotropic m icroporous membrane with high surface porosity. The properties of the composite membrane are mainly determined by the coating layer. The relation between three main factors L_1(effective thickness of the coating layer)?f (penetrat ion degree of the coating material in the microporous substructure)?e(surf ace porosity o f the substructure layer) and Ο_2/N_2 gas separation properties were stud ied on the basis of the model. To obtain composite membranes with a high permeat ion rate, we introduced a pre-coating liquid to the microporous support membrane s and investigated the influence of the pre-coating liquid and coating solvents on the structure and gas permeation rate of the resulting composite membranes.