Small-angle X-ray scattering on fibres of heteroaromatic polymers

Morphological study on poly-p-phenylenebenzobisoxazole (PBO) fiber

“…During the heat treatment process this streak disappears and the four-point pattern, similar to the shape of butterfly, appears. This kind of striation was reported on PPTA fibers, 26 Bai et al 7 and Kumar that current HM fiber, even stronger than former fibers in tenacity, gives us the same pattern. In the case of high-strength polyethylene fiber, 27 this Recently Martin et al 21 proposed a model that periodic density fluctuation acts as a weak point explains the possibility that a chain end of PBO on tensile strength.…”

“…Dow developed a morphology of PBO fiber. [3][4][5][6][7] Krause et al 3 studied new synthesis route of monomer, polymerization, crystal size and the morphology by wide-angle X-ray scattering (WAXS), dark-field (DF) images of transmission electron microscope (TEM), and chamber was used. The sample yarn and the imaging plate were installed in the chamber.…”

A Novel Random Preferential Orientation of the Crystal A‐axis Along the Radial Direction Confirmed on the Poly‐<i>p</i>‐phenylenebenzobisoxazole (PBO) Fiber Made with a Water

“…The fiber can be spun from dope (concentrated solution) made from PBO molecules and poly-phosphoric acid, then coagulated, washed, dried and heat-treated if necessary. Because the PBO molecule take a relatively straight conformation in the fiber, the molecular orientation is proved to be very high along the fiber axis, whereas the interaction between molecules normal to the fiber direction is not so strong [4][5][6][7][8][9][10][11][12][13][14][15][16][17] . Therefore, the fiber shows relatively small crystallite size, especially along the a-and b-axes.…”

The Effect of Non-Aqueous Coagulation in the Structure of Poly-<i>p</i>-phenylenebenzobisoxazole (PBO) Fibers

“…To improve this mechanical properties much higher, we have been looking into the structural formation of fiber during coagulation and found that a non-aqueous coagulant gives a different fiber structure 1 . The fiber is expected to have a higher molecular orientation with less structural inhomogeneity along the fiber axis, which has been revealed by small and wide-angle X-ray diffraction (SAXS and WAXS) techniques and high-resolution transmission electron microscope (HREM) observation [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] . Figure 1 shows the relationship between fiber modulus and the crystallite orientation of the (200) diffraction of the PBO crystal estimated by X ray, in which the three fibers show high molecular orientation to the fiber axis than other conventional fibers 19 .…”