Lattice defects in poly(p-phenylene-terephthalamide) fibers

Abstract

The lattice defects in PPTA fibers were studied by line profile analysis. The results indicate that lattice distortions are produced by local defects, probably chain ends incorporated into the crystalline lattice. The disorder is strongly anisotropic. There are indications for the existence of small domains of higher disorder which do not disappear on annealing.

Crystallite size evolution of aramid fibres aged in alkaline environments

“…Precisely this different dependency is the basis of methods introduced to separate size broadening from strain broadening, such as the Hosemann method [25] for the determination of the crystallite size and the paracrystalline distortion factor. For aramids it is well known that strain broadening is an important aspect of the diffraction pattern [26]. Strain broadening increases with the order of the reflection, whereas size broadening does not (expressed in terms of the magnitude of the diffraction vector).…”

“…higher reflection orders) for the Hosemann method are present it has been applied in the literature to determine longitudinal structural parameters of aramids [28]. Yet, application of the Hosemann method to aramids is questionable, as was reported by Krenzer and Ruland [26]. According to these authors the 006 reflection can not be used since it contains a contribution of the 106 reflection.…”

Synchrotron X-ray diffraction of a single filament and a bundle of poly (p-phenylene terephthalamide) filaments

“…The highly oriented high-tenacity/ high-modulus para-aramide fibers of poly (p-phenylene terephthalamide) ( P P T A ) have been studied using X-ray diffraction (for examples, see Refs. [1][2][3][4][5] in bundle form and light diffraction6 while stressing a single filament. Based on X-ray diffraction, electron diffraction, sonic and polarizing microscopic techniques, as well as macroscopic mechanical measurements of PPTA fibers, Schaefgen7 wrote an informative review on the structure, properties, and applications of PPTA fibers, known as Kevlar ( a DuPont trademark) or Arenka ( a n Enka trademark) fibers.…”