Novel Fine Structures in Poly-p-phenylenebenzobisoxazole Fibers Induced by Water Vapor, Hot Water, and Non-Aqueous Coagulation II Random and Radial Preferential Orientations of the Crystal a-Axis

摘要

The preferential orientation of the a-axes of poly-p-phenylenebenzobisoxazole (PBO) crystals in PBO fibers made with differential coagulation processes is characterized. Electron diffraction and micro-focus X-ray diffraction were carried out for this purpose. To estimate the alignment quantitatively a two-phase model is proposed and the calculated X-ray diffraction profiles fit well with the measured profiles. Water vapor coagulation at high temperature gave mostly almost random preferential orientation while a non-aqueous coagulation produced radial orientation. The fibers made with hot liquid water coagulation were characterized as a middle form between the limits of radial and random orientations.