Tadahisa Iwata

Lamellar single crystals of poly(l-lactic acid) (PLLA) were grown from a 0.05% solution of p-xylene at 90 °C. The hexagonal, truncated-lozenge and lozenge-shaped single crystals with spiral growth were prepared simultaneously, and these crystals were relatively stable under conditions of electron bombardment. The hexagonal and lozenge-shaped crystals gave well-resolved electron diffractograms from which the reciprocal lattice parameters a* = 0.935 nm-1, b* = 1.626 nm-1, and γ* = 90° could be det

The biodegradability of aliphatic polyesters, which are produced by biosynthesis and chemosynthesis, strongly correlates to the polymer morphology such as crystallinity, molecular orientation, chain packing and crystal surface, in addition to the chemical structure. For elucidation of biodegradation mechanism of crystal regions on an atomic level, lamellar single crystals of poly([R]-3-hydroxybutyrate) (P(3HB)) and its copolymers, poly([R]-3-hydroxyvalerate) (P(3HV)), poly(4-hydroxybutyrate) (P(

Non-biodegradable microplastics have become a global problem. We propose a new enzyme-embedded biodegradable plastic that can be self-biodegraded anytime and anywhere. Proteinase K from <i>Tritirachium album</i> was embedded in poly(l-lactic acid) (PLLA). The PLLA solution-cast film with embedded proteinase K showed weight loss of 78% after 96 h incubation. In addition, PLLA extruded films embedding immobilized proteinase K encapsulated in polyacrylamide were produced at 200 °C and embedded-enzy

Abstract Summary: Biodegradable poly[( R )‐3‐hydroxybutyrate] (P(3HB)) fibers with high tensile strength of 1.32 GPa were processed from ultra‐high‐molecular‐weight P(3HB) by a method combining cold‐drawing and two‐step‐drawing procedures at room temperature. The distribution of molecular structures in a mono‐filament was analyzed by micro‐beam X‐ray diffraction with synchrotron radiation. It was revealed that the P(3HB) fiber has a new core‐sheath structure consistent with two types of molecula

Poly[(R)-3-hydroxybutyrate] (P(3HB)) and its copolymers are accumulated by a wide variety of microorganisms as intracellular carbon and energy material, and are extensively studied as biodegradable and biocompatible thermoplastics. However, these microbial polyesters have not been recognized as practical because of their stiffness and brittleness. Recently, by new drawing techniques, we succeeded in obtaining strong fibers and films from microbial polyesters, produced by both wild-type and recom

Single crystals of bacterial poly[(R)-3-hydroxybutyrate] (P(3HB)) with different molecular weights (Mn = 2500 and Mn = 48 000) were prepared in a mixture of chloroform and ethanol. The enzymatic degradation of P(3HB) single crystals with extracellular PHB depolymerase purified from Pseudomonas stutzeri YM1006 was investigated by transmission electron microscopy, atomic force microscopy, and gel-permeation chromatography. Adsorption of PHB depolymerase on P(3HB) single crystals was examined using

Poly[(R)-3-hydroxybutyrate] (P(3HB)) single crystals, which had different morphologies with and without chain-folding surfaces, were grown from dilute solutions of chloroform and ethanol. Two types of extracellular PHB depolymerases purified from Alcaligenes faecalis T1 and Comamonas acidovorans YM1609, defined as types I and II according to the position of the lipase box in the catalytic domain, were used in the enzymatic degradation and adsorption experiments. The enzymatic degradation of P(3H

Abstract Solution‐grown lamellar single crystals of poly(ϵ‐caprolactone) (PCL) were prepared from a dilute solution of n ‐hexanol by the isothermal crystallization condition or the self‐seeding method. Hexagonal‐shaped lamellar crystals with and without spiral growth were obtained, and the crystals produced well‐resolved electron diffraction diagrams. The chain‐packing structure and morphological complexity in lamellar crystals were investigated by bright‐field and dark‐field diffraction contras

A new core−sheath structure constructed by two kinds of molecular conformations2/1 helix (α-form) and planar zigzag (β-form) conformationsin biodegradable poly[(R)-3-hydroxybutyrate] (P(3HB)) fiber was revealed by 0.5 μm microbeam X-ray diffraction in synchrotron radiation. P(3HB) fiber processed by a method combining cold-drawing and two-step-drawing has both α-form and β-form molecular chains in the core region, while the sheath region consists of only α-form chains. The crystallinity and orie