Organic-inorganic membranes prepared from polyether diamine and epoxy silane

Organic-inorganic polymer membranes were prepared by reacting 3-glycidoxypropyl trimethoxysilane with diamines containing polyether segments, followed by hydrolysis and condensation with acid catalysis. The films were characterized by nuclear magnetic resonance and by dynamic mechanical analysis. The rigidity of the films increased with increasing epoxy content and also with addition of tetraethoxy silane (TEOS) to the reacting medium. Water absorption experiments showed that the diffusivity is decreased with increasing TEOS content. Membranes were evaluated for nanofiltration giving cut offs down to 860g/mol (with a water flux of 2.5l/hm²bar). For gas separation, CO₂/N₂ selectivity values up to 89 were obtained with CO₂ permeability of 125Barrer. Copyright (C) 1999 Elsevier Science B.V.