Abstract
Membrane formation process of cellulose acetate (CA) for ultrafilter and the performance of the resulting membrane were studied. The membranes coagulated from a dimethyl sulfoxede (DMSO) solution of CA with water have a wide range of ultrafiltration rates (UFR) and high rejections of protein. These membranes have also good permeability properties for low and middle molecular weight (approximate 1000) molecules. It is assumed that a low coagulation value of DMSO causes the rapid precipitation of CA polymer-aggregate network, forming a porous membrane structure. Water permeability increases by diluting the composition of casting solutions, i.e., UFR is proportional to the third power of DMSO/CA ratio. A packed-bed-like membrane structure is proposed from the observation of electron microscanning and the above consideration of permeability properties.
