SPINNING OF CELLULOSE-ACETATE HOLLOW-FIBER BY DRY-WET TECHNIQUE OF 3C-SHAPED SPINNERET

Cellulose acetate hollow fibers were spun by a new method-a dry-wet sp inning technique of a 3C-shaped spinneret. The spinning technique para meters effecting the form and the reverse osmosis performances of the hollow fiber were investigated in detail, such as polymer concentratio n, the kind of solvent and additive, spinneret temperature, extrusion rate, evaporation distance, and take-up rate. Heat treating for differ ent times in several treating baths was tested. The results showed tha t cellulose acetate hollow fiber spun by this method is feasible and i s a kind of ''loose'' reverse osmosis membrane and suitable to operate at ultralow pressure, 0.8 MPa, and exhibits a higher flux rate at a s alt rejection of 60-85% for tap water. Cellulose acetate hollow fiber for ultralow pressure reverse osmosis should find wide application in industrial processes. (C) 1996 John Wiley & Sons, Inc.