Evaluation of\nthe Highly Ordered Structure, Ligature,\nand Enzymatic Degradation of Poly[(<i>R</i>)‑3-hydroxybutyrate-<i>co</i>-4-hydroxybutyrate] Elastic Porous Fibers

We\nprepared biocompatible elastic fibers with high porosity\nand\nhigh tensile strength from poly[(<i>R</i>)-3-hydroxybutyrate-<i>co</i>-4-hydroxybutyrate], which is a microbial polyester that\ncan be produced from renewable carbon resources by isothermal crystallization.\nIt was possible to control the pore size by adjusting the isothermal\ncrystallization time. Most of the pores were approximately less than\n10 μm in diameter, did not penetrate, and were distributed discontinuously\nthroughout the fibers. The elasticity of the fibers was apparently\nattributable to the generation of tie molecules with planar zigzag\nconformations between lamellar crystals and to the deformation of\nthe pores. The ligature area occupied by the porous fibers in surgical\nknots was reduced by 75% compared with that of nonporous fibers. This\nis expected to make the ligature more difficult to untie and reduce\nthe feeling of foreign matter. X-ray tomography revealed that the\nporous fibers had a relatively small fiber diameter owing to the collapse\nof the porous area. The rate of enzymatic degradation of the porous\nfibers was more than four times that of nonporous fibers. These results\nsuggest that this elastic porous fiber will have many applications,\nincluding in the medical and marine material fields.