UV誘導接枝丙烯酸於聚醯胺/聚丙烯腈超薄複合薄膜並應用於滲透蒸發分離醇類水溶液之研究

Pervaporation of aqueous alcohol mixtures through a UV grafted acrylic acid onto polyamide/polyacrylonitrile TFC membrane

張銘維(Ming-Wei Chang)

指導教授 ： 李魁然 ； 黃書賢

中原大學/工學院/化學工程研究所/碩士(2012年)

https://doi.org/10.6840/cycu201200620

摘要

本研究使用二胺單體1,4bis(3-aminopropyl)piperazine(BAPP)與醯氯單體　trimesoyl chloride(TMC)於polyacrylonitrile(PAN)非對稱基材膜上進行界面聚合反應，製備一聚醯胺複合薄膜(polyamide/PAN thin-film composite membrane, PA/PAN TFC membrane)。為了抑制在高濃度醇類進料操作下聚醯胺選擇層產生之膨潤現象，試圖利用UV聚合法接枝上丙烯酸單體(acrylic acid, AA)改質聚醯胺複合薄膜，並應用於滲透蒸發分離醇類水溶液上。研究中利用全反射式傅立葉轉換紅外線光譜儀(ATR-FTIR)與X射線光電子能譜儀(XPS)鑑定聚合層的化學結構及組成，熱重分析儀(TGA)及熱示差掃描卡量計(DSC)鑑定聚合層之熱學性質，並使用掃描式電子顯微鏡(SEM)與原子力顯微鏡(AFM)分析表面及截面型態與粗糙度。
實驗結果發現經UV接枝聚合後，薄膜表面化學及物理結構產生明顯的變化；聚醯胺接枝聚丙烯酸後之熱重損失及玻璃轉移溫度大幅的改變，這可關聯到分離效能上升的結果；由於接枝上親水性高分子且選擇層厚度無明顯改變，因此可在提升選擇性的情況下，不至於損失其透過量。
　　研究中同時探討接枝聚合條件如UV聚合單體濃度、照射時間、照射強度，對於滲透蒸發分離效能的影響。實驗結果顯示，其最佳接枝聚合條件為：20 wt% 丙烯酸單體溶液，照射時間1min及照射距離30cm，在此情況下所製備的聚丙烯酸-聚醯胺/聚丙烯腈複合膜(polyacrylic acid-polyamide/PAN)應用於滲透蒸發程序分離90wt%乙醇水溶液，具有最佳的分離效能，其透過量大800g/m2h，而出口端水濃度大於99wt% 。在此也探討滲透蒸發操作條件變化，其中包含進料溫度、濃度、不同碳數醇類溶液及真空度高低，對於滲透蒸發分離效能的影響，實驗結果發現此薄膜在大部分條件下均可維持良好的分離效能。

關鍵字

滲透蒸發 ； 聚醯胺 ； UV誘導接枝

並列摘要

The polyamide thin-film composite (TFC) membranes were prepared by the interfacial polymerization of diamine monomer 1,4bis(3-aminopropyl)piperazine(BAPP) and acry chloride monomer trimesoyl chloride(TMC) onto the surface of the asymmetric polyacrylonitrile (PAN) membranes. These TFC membranes were applied in the pervaporation of separating aqueous ethanol solution. In order to improve the pervaporation performance and anti-swelling, the TFC membranes had been modified by means of UV-initiated graft polymerization technique using hydrophilic monomer acrylic acid (AA). Attenuated total reflection infrared spectroscopy (ATR-FTIR) and x-ray photoelectron spectroscopy (XPS) were used to characterize the chemical structures and composition of element of the ultra-thin active layers. The thermal properties of ultra-thin active layer were characterized by thermogravimetric analyzer (TGA) and differential scanning calorimetry (DSC). Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to characterize the surface and cross-sectional morphologies of the polyamide active layers of the TFC membranes.
The results indicated that the polyacrylic acid (PAA) were grafted and entangled on/with the polyamide (PA) polymer chains, causing the increase of glass transition temperature. Meanwhile, the chemical properties, membrane morphology, and surface properties of PAA-PA/PAN were changed significantly. The above results that we mentioned were highly consistent with the pervaporation performance.
The effects of UV-initiated graft polymerization conditions, such as the monomer concentration of acrylic acid, irradiation time, irradiation distance, on the membrane performance were investigated. From the results of the pervaporation separation experiments, the most desirable conditions for the PAA-PA/PAN TFC membrane are as follows: the membrane grafted for 1 min at a 30 cm UV-irradiation distance with 20 wt% acrylic acid monomer solution. The resulting membrane is obtained and has the best pervaporation performance of a 90 wt% aqueous ethanol solution, which is a permeation flux of above 800 g/m2h and a water concentration in permeate higher than 99 wt%. The operating conditions of pervaporation process, such as operating temperature, feed concentration, permeate pressure, feed component, were also investigated.

並列關鍵字

prvaporation ； polyamide ； UV grafted

參考文獻

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