Fibres of the coil-like molecule poly-2,5-benzoxazole (ABPBO) as well as the rod-like molecules poly (p-phenylene benzobisoxazole ) (PBO) and poly (p-phenylene benzobisthiazole ) (PBT) were processed and examined by small-angle X-ray scattering (SAXS). SAXS on thermally annealed ABPBO and PBO fibres consistently showed an off-axis radial four-point intensity pattern. Molecular adjustment due to thermal annealing was believed to cause this unique fibre morphology. The distinct scattering pattern suggested a uniaxial structure of plate-like ordered regions with a tilt-angle off the fibre axis. The tilt-angle was independent of annealing temperature. This fibre morphology is in agreement with complementary evidence from numerical modelling, X-ray diffraction and selected-area electron diffraction. In contrast, SAXS on annealed PBT fibre did not show the radial four-point intensity pattern. This was attributed to the non-colinear and non-coplanar nature of the PBT backbone. For the annealed fibres, the presence of the radial four-point SAXS pattern was not a prerequisite for improvements in tensile properties
Посилання на статтю:
Small-angle X-ray scattering on fibres of heteroaromatic polymers / S. J. Bai and G. E. Price // Polymer. – 1992. – Vol 33. – P. 2136-2142.