Plasticization suppression in grafted polyimide-epoxy network membranes

Abstract

This paper considers the blending of epoxide and diamine components into a glassy polyimide structure (2,2′-bis(3,4′-dicarboxyphenyl) hexafluoropropane dianhydride-2,3,5,6-tetramemyl-l,4-phenylenediamine (6FDATMPDA) intended for use as a gas separation membrane. It is shown that the diamine component can react both with the epoxide component to form an epoxy network and with the polyimide backbone itself, leading to a complex grafted structure. Bulk density and X-ray diffraction results show that this leads to a denser, more amorphous membrane structure. This effect appears to be independent of the diamine structure. Gas permeability is reduced and selectivity increases, consistent with esta..