Novel Fine Structures in poly-p-phenylenebenzobisoxazole (PBO) Fibers Induced by Water Vapor, Hot Water, and Nonaqueous Coagulation III. Random and Radial Preferential Orientations of the Crystal b-Axis

Abstract

ABSTRACTThe preferential orientation of the crystal b-axis in PBO fibers was estimated from the diffraction intensities of micro-focus X-ray diffraction patterns. The observed X-ray diffraction intensities were compared with the calculated scattering volume in the fiber, with the crystal planes of the (010) and () giving coherent X-ray diffraction intensities on the detector. The calculation for the scattering volume was carried out based on an extended method of a previously-proposed two-phase model, which was utilized to predict the scattering volume by searching for the suitable crystal planes in the fiber according to Bragg's Law. Agreement was achieved between the predicted and measured intensity profiles for the (200) and () diffraction intensity profiles.