Gas permselectivity of novel polypyrrolone—Silica hybrid membranes

Abstract

AbstractGas permselectivity behaviors of novel thermally‐rearranged polypyrrolone (PPL)—silica hybrid membranes obtained by applying thermal rearrangement of poly(ortho‐amino imide) as a precursor polymer and sol–gel reaction using tetraethoxysilane were investigated. Gas permeability of neat PPL membranes improved with the increase in rearranged temperature, which was brought by the increased fractional free volume attributed to the enlargement of intermolecular chain distance. H2/CH4 and CO2/CH4 separation abilities of the PPL—silica hybrid membranes improved and tended to cross‐corresponding upper bound trade‐off lines as the silica content increased. The admirable H2/CH4 and CO2/CH4 separation abilities would be provided by the cooperative effect of high fractional free volume derived from the conversion toward PPL and expansion‐suppressed free volume elements at the polymer—silica interfaces.