Effects of Thermal History in the Fiber Production on Preferential Orientations of Molecular Planes of Rigid-Rod Polymers along the Radial Direction Normal to the Fiber Axis

The research described in this article was primarily concerned with the preferential orientations of crystal planes along the radial direction normal to the fiber axis, using fibers of poly-p-phenylenebenzobisoxasole as an example. The focus is placed on the formation of the preferential orientation during the dry-jet wet spinning fiber production process for rigid-rod polymers in which, after coagulation, the fibers are washed and dried at low temperatures. It is suggested that the formation of the radial or random preferential orientation was determined in the coagulation and washing processes, based on an analysis of micro-focus X-ray diffraction intensities in a synchrotron radiation facility.