X-ray data from a cyclic tensile study of melt-spun poly(3-hydroxybutyrate) P3HB fibers: A reversible mesophase

Abstract

Wide-angle x-ray diffraction (WAXD) patterns that show mesophases in core-sheath bicomponent fibers and amorphous fibers are presented in section 1.1 of the article. Section 1.2 presents molecular dynamics simulations and scattered intensity calculations of stretched P3HB chains. Sections 1.3–1.6 summarize WAXD and small-angle x-ray scattering (SAXS) data analysis from a tensile study of melt-spun P3HB fibers. Azimuthal profiles are extracted from 2D WAXD patterns at various angular regions and the positions of equatorial reflections and corresponding d-spacings are summarized. Additionally, the extracted structural parameters from SAXS images are summarized. The tensile stress calculations, crystal orientation calculations, applied intensity corrections, calculations of long spacings, coherence lengths and lamellar diameters are explained in the methods subsections 2.3.1–2.3.7. WAXD and SAXS measurements of P3HB fibers were recorded on a Bruker Nanostar U diffractometer (Bruker AXS, Karlsruhe, Germany). The recorded WAXD/SAXS patterns were analyzed with the evaluation software DIFFRAC.EVA (version 4.2., Bruker AXS, Karlsruhe, Germany) and python codes. For more information see ‘Tensile study of melt-spun poly(3-hydroxybutyrate) P3HB fibers: Reversible transformation of a highly oriented phase’ (Perret et al., 2019).

Tensile study of melt-spun poly(3-hydroxybutyrate) P3HB fibers: Reversible transformation of a highly oriented phase

“…ii) Other amorphous fibers show similar equatorial reflections: We have already observed similar equatorial reflections for various drawn fibers melt-spun from amorphous polymers [18,31,32].…”

“…The tensile stress was applied using a TS 600 tensile stage (Anton Paar GmbH, Graz, Austria) equipped with load cell LC-5N being capable of measuring forces up to 5 N. The calculation of applied tensile stresses is given in the data in brief article [18]. Single filaments were used for all WAXD and SAXS measurements, which were performed in two separate experiments with distances of 16.8 cm and 144.4 cm, respectively, between the sample and the active detector area.…”

“…Peaks in, e.g., azimuthal WAXD scans were fit with Pearson VII distribution functions using python codes [20]. Herman's equation [18] was applied in order to extract the orientation parameter f (hk0) of the α-form crystals [21]. If f ሺ୦୩ሻ = 1 then the (hk0) planes of the crystals are completely aligned parallel to the fiber axis and if f ሺ୦୩ሻ = 0, then the crystals are randomly oriented.…”

“…If f ሺ୦୩ሻ = 1 then the (hk0) planes of the crystals are completely aligned parallel to the fiber axis and if f ሺ୦୩ሻ = 0, then the crystals are randomly oriented. Long-spacings, coherence lengths and lamellar sizes were calculated by analyzing meridional and transversal areas of the SAXS pattern [18]. The performed intensity corrections to the WAXD/SAXS patterns due to the thinning of the fibers under tensile stress are explained in the data in brief article [18].…”

“…Long-spacings, coherence lengths and lamellar sizes were calculated by analyzing meridional and transversal areas of the SAXS pattern [18]. The performed intensity corrections to the WAXD/SAXS patterns due to the thinning of the fibers under tensile stress are explained in the data in brief article [18].…”