In-situ wide-angle X-ray scattering of a sheared thermotropic random copolyester amide revealed monomeric sequence segregation in the liquid crystalline phase. The copolyester amide is based on 60 mol% 2,6-hydroxynaphthoic acid, 20 mol% terephthalic acid and 20 mol% amino phenol (designated N-T-AP). The solid phase exhibits unusual crystallinity and the fiber X-ray diffraction exhibits aperiodic meridional reflections consistent with sequence segregation along the chain. In the liquid crystalline phase at 305 °C polarized optical microscopy showed a “worm” texture, and X-ray scattering showed an amorphous halo denoting no preferred macromolecular orientation. Upon application of shear the X-ray pattern became anisotropic with an increase of intensity on the equatorial axis consistent with the macromolecules being aligned along the flow axis. Strikingly, the X-ray pattern also exhibited a meridional reflection in the melt indicative of spatial monomer register along chains axes. Increasing the shear rate increased the equatorial intensity and reduced the azimuthal spread of the meridional reflection corresponding to an increase of longitudinal monomer register. The monomer register was preserved over a range of temperatures and upon quenching the polymer under shear. Therefore, the unusual crystallinity in solid state would be explained by the existence of monomer sequence segregation already present in the melt.

中文翻译：

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热致共聚酯酰胺液晶相中的单体序列偏析。原位 X 射线散射


剪切热致无规共聚酯酰胺的原位广角 X 射线散射揭示了液晶相中的单体序列偏析。共聚酯酰胺基于 60 mol% 2,6-羟基萘甲酸、20 mol% 对苯二甲酸和 20 mol% 氨基苯酚（称为 NT-AP）。固相表现出不寻常的结晶度，纤维 X 射线衍射表现出与沿链的序列偏析一致的非周期性子午反射。在 305 °C 的液晶相中，偏光光学显微镜显示出“蠕虫”纹理，X 射线散射显示出无定形光晕，表明没有优选的大分子取向。施加剪切力后，X 射线图案变得各向异性，赤道轴上的强度增加，与沿流动轴排列的大分子一致。引人注目的是，X 射线图谱还在熔体中表现出子午反射，表明沿链轴的空间单体配准。增加剪切速率会增加赤道强度并减少子午反射的方位角扩展，这与纵向单体记录的增加相对应。在一定温度范围内以及在剪切下淬火聚合物时，单体记录得以保留。因此，固态下异常的结晶度可以通过熔体中已经存在的单体序列偏析来解释。