濕式相轉換法中延緩成型時間對非對稱中空纖維膜內皮層之控制

Effect of Delay Demixing Behavior of Polysulfone in Phase Inversion Process on the Skin Layer Structure of Hollow Fiber Membranes

本研究以濕式相轉換法製備非對稱中空纖維膜使具體完整皮層，並利用光穿透測試，探討沉澱槽中延遲成膜時間對於皮層成形之影響，藉此提升非對稱中空纖維膜之分離乙醇水溶液之效能。首先以光穿透試驗探討以不同碳數之醇類作為沉澱劑，討論沉澱劑極性差異對非對稱中空纖維膜延遲成型對膜型態之影響，研究中改變核心液之組成條件，製備出不同內皮層結構之中空纖維膜，結果發現以正丁醇作為沉澱劑能製備出最佳緻密之內皮層結構，研究中同時以不同磺酸程度之聚嘲諷高分子做為膜材，探討高分子極性差異對於內皮層構造之影響，並將上述非對稱中空纖維膜應用於乙醇水溶液之研究，並探討非對稱膜內皮層結構差異對滲透蒸發選擇性效能之影響，研究發現磺酸化高分子因極性改變於成膜系統中形成不同成膜路徑，藉由沉澱劑極性差異可有效控制中空纖維膜內皮層之結構，以正己烷／正丁醇中配製成1:1之比例作為核心液之組成，可延緩磺酸化膜之成型時間獲得良好內皮層，獲得較佳之滲透蒸發分離效能。

The purpose of this study is to prepare the defect free skin layer of hollow fiber membrane via the wet phase inversion process. The effect of delay demixing rate of casting solution on the skin layer structure was investigated by using the light transmittance measurements. The dense skin layer hollow fiber membranes were applied for dehydration of ethanol solution by pervaporation. The effects of carbon number of the alcohols as the coagulant in phase inversion process on the light transmittance were studied. It was found that the polarity difference between the alcohols strongly affected the demixing rate of the casting solution in water bath. It is indicated that low polarity coagulant n-butanol showed the significantly delay demixing effect in the wet phase inversion process. The hollow fiber membrane showed the largely enhancement on the separation performance in pervaporation. On the other case, the sulfonated polysulfone hollow fibers were prepared following the above procedure. The poor performance was found due to the less demixing time in coagulant bath. The mixed coagulant with n-hexane and n-butanol were used as the coagulant in membrane preparation. It was found that the polarity change in n-hexane additive induced the delay demixing behavior in sulfonated piolysulfone solution. The skin layer structure became denser with declining the polarity coagulant in membrane formation. It was concluded that the equivalence n-hexane and n-butanol as the core liquid in hollow fiber formation obtained the best skin layer structure.