Preparation of porous carbons from phase-inversion membranes was inves
tigated as a control method of pore structure in carbon materials. The
structure in carbon films was estimated by means of electron microsco
py, mercury porosimetry, and gas-adsorption methods. When phase-invers
ion membranes of Kapton-type polyimide were carbonized, they maintaine
d the film form and gave macroporous carbon films having high porosity
. However, micro- and mesopore structures in the carbon films were not
influenced by phase inversion in the polymer stage, and, thus, the ma
croporous carbons had a molecular sieve property similar to that of ca
rbons prepared from nonporous polyimide films. A macroporous structure
in cellulose membranes was similarly maintained through the carboniza
tion step, but some of these were fractured or deformed owing to the l
arge shrinkage. Polymer membranes have a capability as porous carbon p
recursors if they satisfy two requirements: solid-state carbonization
and relatively high carbon yield. A composite membrane of a macroporou
s carbon with a dense carbon having an impervious ability was readily
produced by shaping at the precursor stage. (C) 1995 John Wiley and So
ns, Inc.