pps proceeding - Abstract Preview
pps proceeding
Symposium: Textiles and Fibres
Oral Presentation
 
 

Influence of melt-spinning parameters, drawing and stress annealing on the molecular orientation in poly(3-hydroxybutyrate) fibers investigated by wide-angle X-ray diffraction

Reifler Felix A. (1)*, Hufenus Rudolf (2)

(1) Empa, Swiss Federal Laboratories for Materials Science and Technology - St. Gallen and Dübendorf - Switzerland, (2) Empa, Swiss Federal Laboratories for Materials Science and Technology - St. Gallen - Switzerland

Poly(3-hydroxybutyrate) (P3HB) is a thermoplastic polyester produced by bacteria as intracellular carbon and energy storage compound. P3HB is sustainable, biocompatible and truly biodegradable in aerobic and anaerobic conditions without forming toxic by-products. Due to its exceptional properties, as well as reasonable production costs via the relatively simple biosynthesis process, P3HB qualifies for the use in numerous textile and medical applications. However, melt-spinning of P3HB into fibers poses technical and scientific challenges due to its rapid thermal degradation at temperatures just above the melting temperature and due to the brittleness of native P3HB. Up to now, melt-spinning of P3HB at large scale is not feasible. The issue has been previously addressed in the scientific literature, but at the laboratory scale only. The general aim of this work was to develop an upscalable melt-spinning method for high-strength P3HB fibers. It comprised studies regarding the effects of additives and of modifications of the draw-off unit on the melt-spinning performance of P3HB, and led to fibers exhibiting promising tensile strengths up to 215 MPa. The specific melt-spinning setup and the method we developed to produce P3HB fibers will be introduced. Wide-angle X-ray diffraction (WAXD) data of as-spun and after-treated P3HB fibers will be presented, showing the influence of melt-spinning conditions, drawing and stress annealing on the crystallinity and the molecular orientation in the fibers. It is proposed that the P3HB fibers consist of domains of highly oriented molecules between crystallites. The WAXD data also suggest that besides the oriented crystalline α-phase, a highly oriented amorphous phase is as well present.