凝膠相轉換製備PVDF薄膜及薄膜蒸餾應用

Preparation and characterization of PVDF membranes by phase inversion with gelled dopes and application to membrane distillation

高國翔(kuo-Hsiang Kao)

指導教授 ： 林達鎔

淡江大學/工學院/化學工程與材料工程學系碩士班/碩士(2011年)

https://doi.org/10.6846/TKU.2011.00518

摘要

本研究主要探討聚偏二氟乙烯(PVDF)/二甲基乙醯胺(DMAc)/異丙醇(IPA)三成份所組成的凝膠態製膜液，以相轉換法中的恆溫浸漬沉澱法來製備薄膜。除了探討凝膠態製膜液本身的特性之外，也依傳統濕式製膜程序，改變各項製程變數，以瞭解各個變因對於薄膜成形的影響。藉由流變儀、SEM、DSC、XRD、接觸角、拉力測試等來作膜材物性分析。從XRD的檢測顯示凝膠過程中確實有結晶的產生。製膜液完全凝膠的狀態下，SEM結果顯示，其後續步驟成形的薄膜，其內部結構就不會有太大的變化。例如改變沉澱槽溫度或成份對整體內部薄結構沒有太大的影響。然而，改變沉澱槽溫度或成份時，卻對於薄膜表面形態結構有明顯影響。根據DSC檢測的第一次掃描結果，得知薄膜結晶度約為30%，與XRD結果大致上相符合。
其次，利用上述所製備的多孔性薄膜，將其應用於海水淡化的薄膜蒸餾程序。藉著薄膜的高疏水性，水只能以蒸氣的狀態才能通過薄膜，進而達到純化水的目的。藉由改變不同表面形態的薄膜，探討對純水和氯化鈉水溶液蒸餾滲透通量的影響。從最後的結果中我們得知：（1）表面孔洞所佔面積越多，其滲透通量越大；（2）薄膜表面流體流速越大，其滲透通量也越大。

關鍵字

濕式成膜 ； 高分子凝膠 ； 薄膜蒸餾 ； PVDF

並列摘要

The first part of the present research focused on the investigations of the dopes in gel state consisting of poly(vinylidene fluoride) (PVDF) / N,N-Dimethylacetamide (DMAc) / Isopropanol (IPA), and the membrane formation following the gel state by using the traditional immersion-precipitation method, where DMAc and IPA were used as the solvent and nonsolvent, respectively. The characterization of gels and membranes were done with Rheometry, SEM, DSC, XRD, Universal Testing Machine, and contact angle measurement to study the effect of processing parameters.
The second part concerned the application of the aforementioned porous membranes to membrane distillation for desalination of sea water. The membrane distillation is a process where only the water vapor permeates through the membrane. By varying the surface morphology of membranes and other parameters of operation, the permeate flux from sodium chloride solution was investigated. The results are：
The greater flux can be obtained with increasing surface pore area as well as superficial velocity of fluid.

並列關鍵字

PVDF ； wet method ； membrane distillation ； physical gel

參考文獻

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