Rotational Disorder in Poly(p-phenylene terephthalamide) Fibers by X-ray Diffraction with a 100 nm Beam

Abstract

Single fibers of poly(p-phenylene terephthalamide) (PPTA; brand names Kevlar x , where x = 29, 49, 149) have been scanned with an about 100 nm synchrotron radiation X-ray beam normal to the fiber axis. Models of rotational disorder of the crystalline domains are discussed based on Monte Carlo simulations of the spatial variation of the 110/200 reflection intensities. For Kevlar149 the principal disorder appears to be a rotational domain-disorder across the fiber. The data suggest also the presence of a core and possibly a skin layer, which are both more disordered. Kevlar29,49 appear to have the same type of layering but with different volume fractions. There is also some evidence for a volume fraction without rotational correlation, which might be related to a morphology formed at the onset of coagulation.

Recent synchrotron radiation microdiffraction experiments on polymer and biopolymer fibers

“…This example shows that smaller beam sizes will be required to verify such a model. Current limitation for S-µXRD experiment are for about 100 nm beams [42]. As the formation of such kinks is not well understood [43] it would also be very interesting to perform in situ studies with a fiber bender developed for Raman spectroscopy [44].…”

Global scattering functions: a tool for grazing incidence small angle X-ray scattering (GISAXS) data analysis of low correlated lateral structures

“…GISAXS experiments were carried out at the beamline BW4/HASYLAB using the microfocus option [20][21][22], with a sample-to-detector distance of 1.9 m, a wavelength λ = 0.138 nm, and a beam size of 32 × 17 μm 2 (horizontal × vertical). A compromise between a sufficient separation of specular reflected peaks and Yoneda peaks, a minimized theoretical deviation between DWBA and BA theory (see Sect.…”

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

“…To prove this existence of random distribution theoretically the intensity profile for the (200) plane of the PBO crystal across the fiber is calculated on the basis of a model according to the articles of Riekel and Davies et al 21,24 . If the distribution for the (200) crystal plane is random in the fiber, the number of the plane per volume that satisfy Bragg's law is constant at any point of the fiber.…”

“…Same kind of analysis for analyzing this preferential orientation for PPTA also has been carried out with a micro-focus X-ray diffraction method at the ID 13 beam line of the European Synchrotron Facility (ESRF) 21 . This beam line also reported the presence of the radial preferential orientation for the PBO AS, HM and HM+ fibers 19,22 .…”