Abstract: Poly(furfuryl alcohol)(PFA) synthesized over different catalysts(oxalic acid and iodine) was used to prepare tubular C/CMS composite membranes. TG, FTIR and XRD were employed to characterize microstructure change of carbon membranes during the pyrolysis. Gas separation performance of the carbon membranes was also investigated by molecular probe with pure gases. The results show that the original chemical structure of the two PFA are transformed to turbostratic carbon structure from cross-linking polymeric structure by a series of reactions such as cyclization and aromatization during the pyrolysis. Although they followed similar pyrolysis behavior, the chemical reaction during the pyrolysis and the resultant microstructure of carbon membranes are different. In addition, d(002) and L_a of the carbon membranes polymerized over oxalic acid are smaller while L_c is larger than those polymerized over iodine. This indicates that the microstucture of carbon membranes polymerized over oxalic acid are more ordered and less defected than those polymerized over iodine. Carbon membranes polymerized over oxalic acid show a higher permselectivity and lower permeability.

Key words: Poly(furfuryl alcohol), Carbon membrane, Molecular structure, Gas separation