Evaluation of the Highly Ordered Structure, Ligature, and Enzymatic Degradation of Poly[(R)‑3-hydroxybutyrate-co-4-hydroxybutyrate] Elastic Porous Fibers

We prepared biocompatible elastic fibers with high porosity and high tensile strength from poly­[(R)-3-hydroxybutyrate-co-4-hydroxybutyrate], which is a microbial polyester that can be produced from renewable carbon resources by isothermal crystallization. It was possible to control the pore size by adjusting the isothermal crystallization time. Most of the pores were approximately less than 10 μm in diameter, did not penetrate, and were distributed discontinuously throughout the fibers. The elasticity of the fibers was apparently attributable to the generation of tie molecules with planar zigzag conformations between lamellar crystals and to the deformation of the pores. The ligature area occupied by the porous fibers in surgical knots was reduced by 75% compared with that of nonporous fibers. This is expected to make the ligature more difficult to untie and reduce the feeling of foreign matter. X-ray tomography revealed that the porous fibers had a relatively small fiber diameter owing to the collapse of the porous area. The rate of enzymatic degradation of the porous fibers was more than four times that of nonporous fibers. These results suggest that this elastic porous fiber will have many applications, including in the medical and marine material fields.