EFFECT OF MICROPORE TOPOLOGY ON THE STRUCTURE AND PROPERTIES OF ZEOLITE POLYMER REPLICAS

Zeolites were used as templates to prepare microporous polymer replica s. Phenol-formaldehyde polymers were synthesized and cured within the channel networks of zeolites Y, beta, and L. Dissolution of the alumin osilicate framework in aqueous HF yields an organic replica that conta ins <2% aluminosilicate. The zeolite template exerts important topolog ical effects on the structure and physical properties of the replica. Using zeolites Y and beta, which have three-dimensionally interconnect ed channel structures, the microporosity of the template is reflected in the replica polymer. Pore size distributions are consistent with th e predominance of 5-6 Angstrom walls in the parent zeolite. In contras t, complete collapse of the replica, to a give nonporous material, occ urs upon removal of the zeolite L template, since the latter has a one -dimensional channel structure. TEM and SEM micrographs also show evid ence of collapse in the latter case. Pyrolysis of the zeolite-resin co mposites at 900 degrees C, and subsequent etching, produces very high surface area, electronically conducting replicas. Under these conditio ns the zeolite Y replica has markedly lower conductivity than those ob tained from beta and L, which have straight channels.