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Calculation of alcohol‐acetone‐cellulose acetate ternary phase diagram and their relevance to membrane formation
Author(s) -
Hao Ji Hua,
Wang Shichang
Publication year - 2001
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1259
Subject(s) - cellulose acetate , acetone , methanol , cellulose , chemistry , solvent , cellulose triacetate , membrane , ethanol , cyclohexane , phase (matter) , phase diagram , ternary operation , alcohol , polymer chemistry , chemical engineering , chromatography , organic chemistry , biochemistry , computer science , engineering , programming language
ABSTRACT Alcohol‐acetone‐cellulose acetate phase diagrams incorporated with methanol, ethanol, and isopropanol as nonsolvents are calculated according to a new form of the Flory–Huggins equation. Nonsolvent–cellulose acetate interaction parameters are measured by swelling experiments. Concentration‐dependent nonsolvent–solvent interaction parameters are obtained by vapor–liquid equilibrium and the Wilson equation. It is shown that alcohol is a week coagulant compared with water, and water > methanol > ethanol > isopropanol for cellulose acetate. The phase diagrams characteristic of acetone‐cellulose acetate combined with water, methanol, ethanol, and isopropanol as nonsolvents is different, which leads to the different morphological structure of a cellulose acetate membrane. The structure of a water coagulated membrane has large macrovoids from liquid–liquid phase separation. A methanol coagulated membrane has a honeycomb‐like structure from spinodal microphase separation. An ethanol or isopropanol coagulated membrane has a thicker, dense top layer from the delay time phase separation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1650–1657, 2001