教師資料查詢 | 類別: 期刊論文 | 教師: 黃國楨 Hwang, Kuo-Jen (瀏覽個人網頁)

標題:Effect of salt additive on the formation of microporous poly(vinylidene fluoride) membranes by phase inversion from LiClO4/Water/DMF/PVDF system
學年91
學期1
出版(發表)日期2003/01/01
作品名稱Effect of salt additive on the formation of microporous poly(vinylidene fluoride) membranes by phase inversion from LiClO4/Water/DMF/PVDF system
作品名稱(其他語言)
著者Lin, Dar-jong; Chang, Cheng-liang; Huang, Fane-ming; Cheng, Liao-ping
單位淡江大學化學工程與材料工程學系
出版者London: Elsevier Ltd
著錄名稱、卷期、頁數Polymer 44(2), pp.413-422
摘要The effect of a salt additive, lithium perchlorate, on the morphology and crystal structure of PVDF membranes prepared by wet phase inversion process was studied. The gelation phase boundaries of the quaternary system, LiClO4/water/DMF/PVDF, were determined at 25 °C. It was found that the gelation lines shifted up progressively with increasing salt contents in this system. For a salt-free casting dope, the formed membrane exhibited a typical asymmetric structure characterized by the skin, parallel columnar macrovoids, and cellular pores. WAXD analysis indicated that PVDF crystallized into ‘α’ (type II) structure in this membrane. By contrast, when PVDF was precipitated from high salt-content dopes (e.g. ≥5 wt%), the macrovoids bent and extended towards the bottom region while the original cellular pores evolved into very large voids. The PVDF crystallites became ‘β’ form (type I) in these membranes. Thermal analysis (DSC) of all membranes showed dual melting peaks at low heating rates (≤5 °C/min), suggesting that the crystallites formed in the immersion–precipitation process were imperfect and they underwent re-crystallization during the heating process. Using low voltage SEM at high magnifications (e.g. 100 KX at 0.55 KV) on uncoated samples, the fine structures (10–20 nm) of the PVDF crystallites were observed. And at very high magnifications (225 KX at 0.59 KV), it was observed that the skin region of the membrane prepared from high salt-content dopes actually contained many nano-pores (e.g. 20 nm). This contributes to the high permeation rate and low solute rejection as revealed from the water-flux measurements.
關鍵字Poly(vinylidene fluoride); Membrane; Crystallization
語言英文
ISSN0032-3861
期刊性質國外
收錄於SCI
產學合作
通訊作者
審稿制度
國別英國
公開徵稿
出版型式電子版
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