In-Situ Synchrotron X-Ray Scattering Studies of Polybenzoxazole Fiber Spinning

Abstract

AbstractInitial results are presented of in-situ wide angle x-ray scattering (WAXS) studies of structure and orientation development in the draw zone during fiber spinning of poly(p-phenylene benzobisoxazole) (PBO) in polyphosphoric acid (PPA). The diffraction patterns show strong [100] and [002] reflections. The coherence lengths found from the [100] and [002] reflections are consistent with those found by electron diffraction and suggest important elements of the microfibrillar morphology may already be present in the texture of the extrudate before coagulation. Increasing extrusion rate is found to produce little improvement in molecular orientation. Molecular orientation initially increases with increasing draw ratio from 1 to 10 but, remains constant for higher draw ratios. These results are compared to an affine deformation model during elongational flow.