A series of polyimide／SnO2 hybrid membranes supported on TiO2／kieselguhr-mullite(K-M)were prepared via a sol-gel process．Their morphologies

chemical structures

thermal performances

pore distribution and gas permeability were characterized by means of TEM

FTIR

TG／DTA

DSC

N2 adsorption and gas permeability measurements．The results showed the SnO2 phase was well dispersed in polyimide matrix．The SnO2 phase connected with the polyimide through the pendant carboxyl groups along the polyimide chain．The polyimide／SnO2 hybrid membranes possessed finely thermal stability．The hybrid membranes showed better separation properties for H2

CO2

N2 and H2O when compared to those of pure polyimide．The separation factors of the polyimide／SnO2 hybrid membranes with 25 wt％ SnO2 are 58．2

42．4

51．2 and 68．8 for H2／N2

CO2／N2

CO／N2 and H2o／N2 contents

respectively．