Preparation Of Copoly (Phthalazinone Ether Sulfone) Hollow Fiber Ultrafiltration Membrane

Copory (phthalazinone ether sulfone)(PPBES) is a novel material for ultrafiltratbn membrane and support membrane of composite membrane with high glasstransition temperat-ure, good mechanical performance and chemical stability, especially excellent flexibility. In this paper, by using PPBES as membrane material and N,N-dimethyl acetamide (DMAc) as solvent, hollow fiber ultrafiltration membranes were prepared with dry-wet spinning technique. The effects of the macro molecular additives, mixing additives, small organic molecules additi-ves and the technology of membrane preparation on the membrane structure and performance were investigated. Also, the conditions of dry-membrane preparation were optimized.We rendered thermodynamics phase diagram of PPBES/DMAC/PVP/H2O by cloud point titration method and then investigated the compatibility and precipitation ability of additives to the casting solution by the phase diagram The results showed that polyvinylpyrrolidone (PVP) promoted the phase separation of the casting solution..The effect of PPBES content on the membrane structure and performance was investigat-ed. It showed that the flux of the membrane decreased with the increasing of PPBES content, while the rejection rate increased. By using PVP as macromolecular additive, PVP and LiCl as mixed additive, butanone, ethylene glycol monomethyl ether(EGME), propionic acid and propanol as organic small molecule additives, the effect of their content on the membrane structure and performance were investigated. The results showed that with different type and different content of additives, hollow fiber ultrafiltratbn membrane with different structure and separation performance could be prepared successfully.The influence ofdry-spinning path and coagulation temperature on the membrane perfor-mance was also studied. The results found that under different humidity conditions, dry-spinning path had different effect on membrane performance. In conditions of high humidity, the longer the dry-spinning path was, the higher the flux was; while in conditions of low humidity, the longer the dry-spinning path was, the lower the flux was. Both of them had little change in the rejection rate of PEGl0000. Through the investigation of the coagulation temper-ature, we found that the flux increased significantly with the increasing of the coagulation temperature, while the rejection rate changed little. The optimized conditions of dry-membrane preparation were studied. The results showed that the PPBES hollow fiber ultrafiltration membrane soaked in30%aqueous solution of glycerol which was30℃, and immersed for2hours, then was dried at13℃, the flux could be maintained above94%of the wet film and the rejection rate remained unchanged. The dry-membrane prepared under the optimized condition was stored50days, its performance was still well maintained.