Abstract
Our previous proposal of a folded-chain model for the smetic copolyesters composed of azoxydibenzoate (mesogen group) and oligo-oxyethylenes (spacers) has been examined in terms of the orientation behavior of the molecular segments and the mesogen layers under shear flow induced during extrusion through conical dies. Small- and wide-angle X-ray diffraction analyses of the fibers extruded from smectic states revealed the characteristic orientation of the mesogen groups and their layers. The former oriented perpendicular to the extrusion direction (fiber axis) and the latter with the wide surfaces of lamelae parallel to the extrusion direction. These facts suggest that the basic flow units in the smectic phase have a lamellar structure which consists of mesogen layers. This basic structure in smectic states, as well as the orientation in solid (crystalline) state extrudates and the crystallization behavior from smectic states, suggests the prevalence of a folded-chain structure in smectic states, at least for the copolyesters studied in this work.
