Structural response of melt-spun poly(3-hydroxybutyrate) fibers to stress and temperature. (27th May 2020)

• Record Type: Journal Article
• Authors: Perret, Edith; Reifler, Felix A.; Gooneie, Ali; Chen, Kang; Selli, Figen; Hufenus, Rudolf
• Is Part Of: Polymer. Volume 197(2020)
• Publication Date: 2020-05-27
• Subjects: Poly(3-hydroxybutyrate) -- Melt-spun fibers -- X-ray diffraction; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; 547.7
• DOI: 10.1016/j.polymer.2020.122503
• Languages: English
• ISSNs: 0032-3861

Abstract

Abstract: We have investigated the structural response of melt-spun poly-3-hydroxybutyrate (P3HB) fibers to stress and temperature and its impact on the mechanical properties. Low-stress (≤1.6 MPa, 100–130 °C) annealed P3HB fibers showed a considerable viscoelastic behavior and remained ductile up to at least two months. Stress annealing with high weights (≥32 MPa), however, lead to fibers with a higher tensile strength (182 MPa) and with a lower elongation at break (22%). These significant differences in the tensile properties are closely related to structural changes, which we have studied with in-situ wide-angle x-ray diffraction (WAXD) and small-angle x-ray scattering (SAXS) experiments. A highly oriented non-crystalline mesophase (Pnc ), which is located in-between orthorhombic α-crystals is growing during high-stress annealing but disappears during low-stress annealing. However, it is possible to restore the mesophase by post-drawing. The viscoelastic hysteresis behavior of low-stress annealed fibers is explained by a reversible transformation of α-crystals into mesophase and back. Graphical abstract: Image 1 Highlights: Low stress annealing leads to viscoelastic P3HB fibers. Detailed SAXS and WAXD analysis during stress-annealing and drawing of P3HB fibers. Structural response of P3HB fibers to stress and temperature. MD simulations about the transformation of mesophase into P3HB α-crystals.