Premium
Pore size of microporous polymer membranes
Author(s) -
Yasuda H.,
Tsai J. T.
Publication year - 1974
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.1974.070180316
Subject(s) - microporous material , membrane , polysulfone , porosity , permeability (electromagnetism) , materials science , polymer , chemical engineering , knudsen diffusion , chromatography , polymer chemistry , chemistry , composite material , biochemistry , engineering
Pore sizes of microporous polymer membranes were determined by the calculation based on the gas permeability of porous media. The gas permeability coefficient K (given by J = K Δ p / l , where J is the steady‐state gas flux, Δ p is the pressure, difference, and l = the thickness of a membrane) for porous membrane can be given generally by\documentclass{article}\pagestyle{empty}\begin{document}$$ K = K_0 + \frac{{B_0 }}{\eta }\Delta \bar p $$\end{document} where K 0 is the Knudsen permeability coefficient, η is the viscosity of the permeant gas, B 0 is the geometric factor of a membrane, and Δp̄ is the mean pressure of the gas on both sides of a membrane. From gas permeability measurements which yield the pressure dependence of gas permeability coefficient (expressed as above equation), the mean pore size of the porous membrane can be estimated as\documentclass{article}\pagestyle{empty}\begin{document}$$ m = \left( {\frac{{B_0 }}{{K_0 }}} \right)\left( {\frac{{16}}{3}} \right)\left( {\frac{{2RT}}{\pi }} \right)^{{\raise0.7ex\hbox{$1$} \!\mathord{\left/ {\vphantom {1 2}}\right.\kern-\nulldelimiterspace} \!\lower0.7ex\hbox{$2$}}} M^{ - {\raise0.7ex\hbox{$1$} \!\mathord{\left/ {\vphantom {1 2}}\right.\kern-\nulldelimiterspace} \!\lower0.7ex\hbox{$2$}}} $$\end{document} where M is the molecular weight of the permeant gas. The validity of this method was examined with various Millipore filters of which nominal pore sizes are known. It was confirmed that the method provided a simple and reliable means of estimating mean pore size of microporous membranes. The method was applied to investigate the influence of factors involved in preparation of microporous polysulfone membranes by coagulation procedure. It was found that the mean pore size of porous polysulfone membrane increases with (1) increasing with casting thickness, (2) increasing temperature of coagulation bath, and (3) decreasing concentration of polymer in casting solution (DMF as solvent). Water flux and water flux decline due to compaction are also examined as a faction of pore size, porosity, and the thickness of membranes.