No abstract

Long periodical structure was studied for the crystal of a rigid-rod liquid crystalline BC-6 polyester composed of the 1,4-dihexyl ester of pyromellitic acid and 4,4‘-biphenol with small-angle X-ray scattering (SAXS) and transmission electron microscope (TEM) measurements. The highly oriented crystalline fibers which were prepared by spinning a nematic melt of the sample and succeeding annealing showed well-defined scattering maxima with a spacing in the range of 250−300 Å in the SAXS pattern and the corresponding clear stripes in the TEM photograph. The long spacing is attributed to the crystalline lamellae stacked along the chain axis. This is the first example of long periodical structure in the fully aromatic polymer systems. The origin of the long periodic structure is discussed.