Calculation of Quaternary Phase Diagram of Water-N-Met hyl-2-Pyrrolindone-Additives (Small Alcohols) -Poly (ether sulfone)

The quaternay diagrams of water-N-methyl-2-pyrrolindone(NMP)-additives(small alcohols)-poly(ether sulfone)(PES) were calculated.The effect of small alcohols additives on the quaternay diagrams of water-NMP-additives(small alcohols)-PES and gel-speed were analyzed.In the process of membrane formation,the ratio of additive to solvent in polymer-lean phase increased and then decreased.Such a result implies that small alcohols in the casting solution were priory replaced as compared with the solvent.The more ethanol in the casting solution,the more increment of ethanol concentration in the polymer-lean phase.The more additive in the casting solution of the quaternay membrane,the higher gel speed.The capability of small alcohols to increase the gel speed follows the order: 1-propanol