Abstract
The relationships between molecular aggregation structures and gas permeation properties of thermotropic liquid crystalline polymers which have rnesogenic groups in the main chain and the side group were investigated. Differential scanning calorimetry (DSC), polarizing optical microscopic observation, X-ray diffraction and dynamic viscoelastic measurements were used. The permeabilities of O2 and 2 gases through the polymer liquid crystalline membranes were measured by the volumetric method. Molecular motions of the liquid crystalline polymers were investigated by the dynamic spring analysis method, which was effective for the characterization of the liquid crystalline polymers above the glass transition temperature. In the case of the liquid crystalline polymers with the side chain mesogenic group, it was proved that the polarity difference at the end group of the mesogenic side chain influenced the dynamic viscoelastic properties, molecular aggregation structure and gas permeation properties. The temperature dependence of gas permeation shows a breaking point at the phase transition temperature range. Therefore, it is apparent that the liquid crystalline polymer membranes exhibited gas permeation behavior similar to that of the polymer/liquid crystal composite membrane, which was reported previously.
