Zeolite-filled polyimide membrane containing 2,4,6-triaminopyrimidine

Interfacial void-free Matrimid polyimide (PI) membranes filled with zeolite s were prepared by introducing 2,4,6-triaminopyrimidine (TAP). TAP enhanced the contact of zeolite particles with polyimide chains presumably by formi ng hydrogen bonding between them. The threshold amount of TAP, needed to de press totally the void formation, varied with zeolite type in the order of zeolite 4A approximate to 13X < NaY < 5A < NaSZ390HUA. It was also observed that the threshold amount of TAP could be related with the number of exter nal hydroxyl groups of zeolite particles. The void-free PI/zeolite 13X/TAP membrane showed the higher gas permeability for He, N-2, O-2, CO2 and CH4 w ith a little expense of permselectivity compared with the PI/TAP membrane, while the PI/zeolite 4A/TAP membrane showed the lower permeability but high er permselectivity. The facilitation ratios of the zeolite-filled PI membra nes were strongly affected by the pore size of zeolites. In addition, the m olecular sieving effect of zeolites seemed to take place when the kinetic d iameter of gas penetrants approached the pore size of zeolites. (C) 2001 Pu blished by Elsevier Science B.V.