Manufacturing of PHA as Fibers

Abstract

Poly[(R)-3-hydroxybutyrate] and its copolymers have not been recognized as practical because of its stiffness and brittleness. Recently, we succeeded in obtaining strong fibers by two kinds of new drawing techniques from microbial polyesters produced by both wild-type and recombinant bacteria. The improvement of the mechanical properties of fibers is due not only to the orientation of the molecular chains but is also due to the generation of a planar zigzag conformation. The highly ordered and inner structures of strong fibers with tensile strength of over 1.0 GPa were analyzed by microbeam X-ray diffraction and X-ray microtomography with synchrotron radiation, respectively. The enzymatic degradation of strong fibers was investigated by using an extracellular polyhydroxybutyrate depolymerase. Furthermore, nanofibers were prepared by an electrospining technique from dilute solution and subcutaneous implantation of electrospun nanofibers was performed to investigate their bioabsorption behavior and tissue response. In this chapter, we present the processing, mechanical properties, molecular and highly ordered structure, enzymatic degradation, and bioabsorption of strong fibers and nanofibers produced from microbial polyesters.