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

POLYMER

卷:180

Article

Perret, Edith^1,2  Reifler, Felix A.^1,2  Gooneie, Ali¹  Hufenus, Rudolf¹ 

[1] Empa, Swiss Fed Labs Mat Sci & Technol, Lab Adv Fibers, Lerchenfeldstr 5, CH-9014 St Gallen, Switzerland

[2] Empa, Ctr Xray Analyt, Swiss Fed Labs Mat Sci & Technol, Uberlandstr 129, CH-8600 Dubendorf, Switzerland

关键词: Poly(3-hydroxybutyrate);    P3HB;    Melt-spun fibers;    Melt spinning;    Biopolymer;    WAXD;    SAXS;    X-ray diffraction;   

DOI  :  10.1016/j.polymer.2019.121668

来源: Elsevier

【 摘 要 】

Poly-3-hydroxybutyrate (P3HB) typically crystallizes into the orthorhombic alpha-form. The additional intense and rather broad equatorial reflection in wide-angle X-ray diffraction (WAXD) patterns seen in our melt-spun P3HB fibers cannot be attributed to the a-form crystals. We propose that a non-crystalline mesophase, which consists of disordered but highly oriented and stretched molecules located between alpha-crystals, leads to the observed broad equatorial reflection. We show that the transformation of this mesophase from and into the alpha-form phase is partially reversible under cyclic tensile loading. Structure factor calculations, which are based on atomic positions from molecular dynamics simulations of a set of stretched P3HB molecules, support this model. The WAXD patterns were analyzed with azimuthal, radial, equatorial and meridional scans and the changes in the crystal orientation, changes in the percentages of individual phases and changes in the alpha-crystal lattice spacings were analyzed as a function of the applied tension. Changes in long spacings, crystal sizes and coherence lengths under cyclic loading were determined with small-angle X-ray scattering (SAXS) measurements. The long spacing between alpha-crystals increases when tensile stress is applied and it snaps back to the original spacing when the tensile stress is released.

【 授权许可】

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