The characterization of nylon 6 filaments by x‐ray diffraction

Abstract

SynopsisA method is described for calculating crystallinity indices and crystalline orientation functions for the CY and y components of the crystalline phase of nylon 6 filaments using wide-angle x-ray diffraction (WAXS) analysis. The method is shown to be applicable to a wide range of filament samples ("conventional" as-spun, fast spun, drawn, and annealed) even when only a single broad diffraction maximum is observable from the WAXS photograph. The component indices can be used to illustrate differences present in the filament microstructure which would be unobservable if a total crystallinity index, such as that determined by density, were determined alone. For example, the initially mixed a-y structure is retained in low-temperature drawing (75-15OOC) of nylon 6 fiber, but the predominantly (Y form is produced a t higher draw temperatures.

Microstructural investigation of high-speed melt-spun nylon 6 fibers produced with variable spinning speeds

“…Bankar et al 1 carried out quantitative studies to relate the crystalline orientation of spun fibers with their spinning speed in the range of 100 -1000 m/min. Stepaniak et al 2 described empirical methods for calculating a total crystalline index, crystalline indices for ␣ and ␥ forms, and the corresponding ␣ and ␥ orientation functions for nylon 6 fibers at spinning speeds of 20 -2435 m/min. Also, they characterized the transitions that occurred between the crystal structures and examined the importance of crystal structures other than the well-characterized ␣ and ␥ forms.…”

The Structure and Properties of Typical Melt-spun Fibres

“…Yasuda [516] described the measurement techniques of WAXS and SAXS on PET-fibre filaments, and the apparent crystalline size from the diffraction profiles was calculated by using Scherrer's equation. WAXS and SAXS patterns on nylon 6 [517] and nylon 6.6 [518,519] were obtained to calculate polymorphic crystal structures and the crystal perfection index by using the methods of Stepaniak et al [520] and Dismore and Statton [521], respectively.…”

Die elektronenmikroskopische Darstellung der Morphologie partiell kristalliner Polymere am Beispiel des Polyamid‐6

“…In der Literatur lie@ heute ein urnfangreiches Untersuchungsmaterial aus Messurigen der Rontgenstreuung im Klein-und Weitwinkelgebiet sowohl von PA-6-Fasern als auch von isotropen PA-6-Proben vor; fur eine quantitative Interpretation rontgenographischer Daten sind zahlreiche Auswerteverfahren vorgeschlagen worden [29][30][31]50,73,85,87,93]. Was die Kristallstrukturanalyse anbetrifft, so konnen die beiden Hauptmodifikationen des PA-6, die monokline aund die hexagonale y-Struktur, inzwischen als weitgehend aufgeklart gelten [32,52,60,68,86,971 Was die Elektronenmikroskopie nicht leistet, ist eine weitergehende Differenzierung hinsichtlich der Natur der als ungeordnet bezeichneten Bereiche.…”