(520b) Thermotropic Liquid-Crystal Polymer Membranes for Paraffin/Olefin Separations

Reliable methods to synthesize, characterize, and test thermotropic liquid crystalline membranes are currently being investigated. Polymer/liquid crystalline mixed matrix membranes were prepared with Polysulfone and 4-cyano-4-octyliphenyl (8CB) or N-(4-Methoxybenzylidene)-4-butylaniline (MBBA) by solution casting method. The morphology of the polymer as well as the phase separation during the casting process are important factors for the liquid crystal material to form specific phases. Porous membranes can be utilized as a support for impregnating the liquid crystal inside the domains. The membrane material and pore structure are varied in order to attain specific interactions with the liquid crystal. This is followed by photopolymerization of the liquid crystal, which will improve the physical stability of the supported liquid membrane as well as enhance selectivity. Permeability studies of the separation of light gases (He, O2, N2, CH4, and CO2) and paraffins/olefins in the crystalline, smectic, nematic, and isotropic phases are studied. Sorption behavior will be examined across the transition between crystalline-nematic and nematic-isotropic phases.