國合計畫：非溶劑蒸氣誘導式相分離之探討
Date Issued
2004-05-03
Date
2004-05-03
Author(s)
DOI
922214E002020
Abstract
PEI (polyetherimide) and PMMA(poly methyl methacrylate) membranes were prepared
by coagulation in humid air with a relative humidity of about 70%. Gravimetric measurements
were performed first to analyze the amount of water drawn into casting solution during the
forming of membranes. To get insight into the local concentration change during membrane
formation, two advanced instruments were used, confocal Raman spectroscopy (in France) and
FTIR microscopy (in Taiwan). The results from membrane structure, confocal Raman, and
FTIR microscopy suggest the membrane forming process be described as follows: NMP
migrates to the surface of casting film and draws water to the casting film due to high affinity
of NMP for water; the migration of NMP towards interface results in a polymer concentration
gradient across the casting film, with lower concentration near the surface, which can well
correlate with the pore size distribution across the membrane; the gelation of the polymer-rich
phase after phase separation would reduce the water permeation rate through the casting film
and generates a liquid layer on top of the casting film because the hold up of water. For the
PEI system, we can analyze quantitatively the concentration of polymer, solvent and
nonsolvent and determine the composition paths in the ternary phase diagram, which has never
been reported before in the literature.
Subjects
membrane formation
vapor induced phase separation
Raman confocal spectroscopy
FT-IR microscopy
morphology control
Publisher
臺北市：國立臺灣大學化學工程學系暨研究所
Type
report
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