回淡江大學首頁
Effect of solvent on the dipole rotation of poly(vinylidene fluoride) during porous membrane formation by precipitation in alcohol baths

類別:期刊論文

學年 / 學期:105-2

出版日期:2017-04-21 00:00:00

著者:Hsu-Hsien Chang; Liang-Kuei Chang; Cheng-Dau Yang; Dar-Jong Lin; Liao-Ping Cheng

著錄名稱、卷期、頁數:Polymer 115,頁164-175

摘要:Microporous PVDF membranes were prepared by isothermal immersion precipitation of PVDF/DMSO and PVDF/TEP casting dopes in different alcohol baths. The formed membranes exhibited the so-called particulate morphology, being packed by interconnected crystalline particles of a similar size. For the alcohol/TEP/PVDF system, the particles appeared as sheaf-like spherulites consisting of curled lamellae with thickness of ∼15 nm. In contrast, for the alcohol/DMSO/PVDF system, the formed membranes comprise relatively compact globules whose surface was covered with granular objects of ca. 30 nm dia. Wide angle X-ray diffraction patterns of the membranes indicate that the sheaf-like crystals were of the α-type structure, while the compact globules the γ-type structure, as were confirmed by FTIR-ATR analyses. 19F NMR spectroscopy indicated that PVDF chains exhibited TG+TG− conformation in TEP and T3G+T3G− conformation in DMSO. These conformations remained unchanged during immersion-precipitation to yield the α- and γ-type crystal structures. The crystallinity of the membranes, as determined by X-ray diffraction and differential scanning calorimetry, was found to be ∼68%. Furthermore, desalination by membrane-distillation of 3.5% NaCl(aq) feed at 50 °C were carried to see the desalination capability of the membranes. High fluxes (10–13 LMH) and rejections (∼99.8%) were obtained for both types of membranes.

語言:en_US

期刊性質:國外

審稿制度:

國別:TWN

出版型式:電子版