ISOTROPIC OR ANISOTROPIC POROUS SYNDIOTACTIC POLYSTYRENE MEMBRANE AND MANUFACTURE THEREOF

摘要

PURPOSE: To improve solvent resistance and thermal strain temp. and to improve ultrafiltratability, microfiltratability or the like by forming a thin semipermeable membrane as a microporous membrane consisting of a syndiotactic polystyrene having an isotropic or anisotropic property. CONSTITUTION: A mixture composed of the syndiotactic polystyrene and its solvent is heated to form a uniform fluid having a viscosity sufficient for membrane formation. This uniform fluid is extruded or cast to the membrane and the membrane is passed through such >=1 zone where the membrane solidifies, by which the membrane is rapidly cooled or solidified. The membrane is then passed through >=1 zone where at least the substantial portion of the solvent may be removed from the membrane. The membrane is thereafter leached simultaneously or in succession thereto, by which the thin semipermeable membrane having the isotropic or anisotropic syndiotactic polystyrene microporous structure is formed. The semipermeable membrane having the form of hollow fibers is more adequate.