論文 Characteristic changes in PHBH isothermal crystallization monofilaments by the effect of heat treatment and dip-coating in various solvents European Polymer Journal,134:109808 2020(May 30) Author:Rina Afiani Rebia, Kaho Shizukuishi, Toshihisa Tanaka
Zinc oxide nanoparticles attached to polyacrylonitrile nanofibers with hinokitiol as gluing agent for synergistic antibacterial activities and effective dye removal Journal of Industrial and Engineering Chemistry,85:258–268 2020(Feb. 15) Author:Duy-Nam Phan, Rina Afiani Rebia, Yusuke Saito, Davood Kharaghania, Muzamil Khatri, Toshihisa Tanaka, Hoik Lee, Ick-Soo Kim
Natural antibacterial reagents (centella, propolis, and hinokitiol) loaded into poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate] composite nanofibers for biomedical applications Nanomaterials, SI: Electrospun Nanomaterials: Applications in Food, Environmental, Remediation, and Bioengineering,9:1665 2019(Nov. 22) Author:Rina Afiani Rebia, Nurul Shaheera binti Sadon, Toshihisa Tanaka
Physical properties and in vitro biocompatible evaluation of silicone modified polyurethane nanofibers and films Nanomaterials, SI: Electrospun Nanofibers for Biomedical Applications,9:367 2019(Mar. 05) Author:Chuan Yin, Sélène Rozet, Rino Okamoto, Mikihisa Kondo, Yasushi Tamada, Toshihisa Tanaka, Hatsuhiko Hattori, Masaki Tanaka, Hiromasa Sato, Shota Iino
Biodegradable PHBH/PVA blend nanofibers: Fabrication, characterization, in vitro degradation, and in vitro biocompatibility Polymer Degradation and Stability,154:124-136 2018 Author:Rina Afiani Rebia, Sèléne Rozet, Yasushi Tamada, Toshihisa Tanaka
Preparation and formation mechanism of porous carbon nanosheets by thermal decomposition of polyvinyl alcohol films impregnated with zinc (II) and nitrate ions Solid State Sciences,65:33-40 2017(Mar.) Author:Yoshiyuki Hattori, Rikio Kojima, Kento Sagisaka, Motoki Umeda, Toshihisa Tanaka, Atsushi Kondo, Taku Iiyama, Mutsumi Kimura, Hiroyuki Fujimoto, Hidekazu Touhara
Investigating thermal properties of and melting-induced structural changes in cold-drawn P(3HB) films with - and -structures using real-time X-ray measurements and high-speed DSC Polymer,193(2):181-188 2016(Jun.) Author:Taizo Kabe, Toshihisa Tanaka, Hironori Marubayashi, Takaaki Hikima, Masaki Takata, Tadahisa Iwata,
High Tensile Strength Fiber of Poly[(R)-3-hydroxybutyrate-co -(R)-3-hydroxyhexanoate] Processed by Two-Step Drawing with Intermediate Annealing Journal of Applied Polymer Science,132(2):41258 2015 Author:Taizo Kabe, Chizuru Hongo, Toshihisa Tanaka, Takaaki Hikima, Masaki Takata, Tadahisa Iwata
Physical Properties, Structure Analysis and Enzymatic Degradation of Poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyvalerate] Films and Fibers Degradable Polymers and Materials – Principles and Practice (2nd Edition),1114:171-185 2012 Author:Toshihisa Tanaka, and Tadahisa Iwata
Manufacturing of PHA as Fiber Plastics from Bacteria: Natural Functions and Applications, Microbiology Monographs,14(11):257-282 2010(Jan.) Author:Tadahisa Iwata, and Toshihisa Tanaka
カイコの総合紡糸と大気中の二酸化炭素固定 J. Society of Japanese Women Scientists,11(1):29-43 2010 Author:馬越芳子、秦珠子、木原眞実、永易健一、田中稔久、馬越淳
a-PVA Gelation Affected by Different Ratio of DMSO/H2O in Wide Range of Standing Temperature Journal of Polymer Engineering,28:485-499 2008 Author:Lixing Dai, Satoshi Hijioka, Toshihisa Tanaka, and Kazuo Yamaura
Stereocomplex Formation through Reorganization of Poly(l-lactic acid) and Poly(d-lactic acid) Crystals Macromolecules,41:2852-2858 2008 Author:Masahiro Fujita, Tomoharu Sawayanagi, Hideki Abe, Toshihisa Tanaka, Tadahisa Iwata, Kazuki Ito, Tetsuro Fujisawa, and Mizuo Maeda
Analysis of inner structure in high-strength biodegradable fibers by X-ray microtomography using synchrotron radiation Polymer,48:6145-6151 2007(Sep.) Author:T. Tanaka, K. Uesugi, A. Takeuchi, Y. Suzuki, and T. Iwata Abstract:The observation of the inner structure of materials without pretreatment or damage is a very useful analytical method in the field of materials science as well as in medicine and biology. We have carried out a three-dimensional (3D) analysis of biodegradable polyester bacterial-poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyvalerate](P(3HB-co-3HV)) fibers with hightensile strength (1.07?GPa) using X-ray microtomography with synchrotron radiation. The inner structure of the fibers was visualized at a spatial resolution of 1?μm. There are many fine voids for one-step-drawn P(3HB-co-3HV) fibers after isothermal crystallization from the result of X-ray microtomography. This revealed that the clear streak reflection along the equator in small-angle X-ray scattering is caused by these fine voids. The recalculated tensile strength of one-step-drawn P(3HB-co-3HV) fibers after isothermal crystallization is suggested to be 2.02?GPa, taking the cross-section area with 52.7% (polymer region) into consideration. These fine voids in fibers seemed to be generated by the volume changes due to the contraction of polymer chains during isothermal crystallization. Keywords:Poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyvalerate]; X-ray microtomography; High-strength biodegradable fiber
Mechanical properties and enzymatic degradation of poly[(R)-3-hydroxybutyrate]fibers stretched after isothermal crystallization near Tg Polymer Degradation and Stability,92:1016-1024 2007(Jun.) Author:T. Tanaka, T. Yabe, S. Teramachi, T. Iwata Abstract:Poly[(R)-3-hydroxybutyrate](P(3HB)) fibers with high tensile strength were prepared by stretching the fibers after isothermal crystallization near the glass transition temperature. Two samples with different molecular weights (Mw?=?0.7?×?106 and 4.3?×?106) were used to investigate the effect on tensile strength. Increasing the time for isothermal crystallization of P(3HB) fibers resulted in a decrease in the maximum draw ratio. But, the tensile strength of P(3HB) fibers increased remarkably when the isothermal crystallization time was prolonged to more than 24?h. The tensile strength of low-molecular-weight drawn fibers was higher than that of high-molecular-weight fibers. Therefore, it can be concluded that this procedure does not increase the tensile strength of the high-molecular-weight drawn fibers. This is because, in this drawing method, small crystal nuclei grow initially during the isothermal crystallization process. Then, the molecular chains between the small crystal nuclei that acted as the entanglement points are oriented by stretching. In the case of the high-molecular-weight fibers, because the molecular length between the entanglement points of the small crystal nuclei is too long, the molecular chains are not sufficiently oriented by the stretching process. However, in the case of the low-molecular-weight fibers, the molecular length is suitable for generating the extended chains. Based on the result of X-ray analysis of P(3HB) fibers stretched after isothermal crystallization, fibers have the oriented α-form crystal with 21 helix conformation and β-form with planar zigzag conformation. The enzymatic degradation of the stretched P(3HB) fibers was performed by using an extracellular PHB depolymerase purified from Ralstonia pickettii T1. The enzymatic erosion rate of β-form was faster than that of α-form in the P(3HB) fibers stretched after isothermal crystallization. Keywords:Poly[(R)-3-hydroxybutyrate]fiber; Stretching after isothermal crystallization; Mechanical properties; Enzymatic degradation
Structural Transition of Poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyvalerate]Single Crystals on Heating As Revealed by Synchrotron Radiation SAXS and WAXD Macromolecules,40:2392-2399 2007(Apr.) Author:T. Sawayanagi, T. Tanaka, T. Iwata, H. Abe, Y. Doi, K. Ito, T. Fujisawa, and M. Fujita Abstract:The annealing behavior of poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyvalerate](P(3HB-co-3HV)) crystal was studied by synchrotron radiation small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD). Solution-grown single crystals of P(3HB-co-3HV) with various composition of 3HV (5.3-16.0 mol %) were used in order to examine the effect of 3HV unit on the structural changes on heating. The two-dimensional (2D) SAXS patterns demonstrated that the lamellar thickness of P(3HB-co-3HV) single crystal starts to increase discontinuously at an annealing temperature and that two populations with two different thicknesses of original and reorganized crystals coexist in a temperature range, independent of 3HV composition. This fact means that the 3HV unit with longer side chain does not hinder the jump of lamellar thickness. The 2D WAXD and differential scanning calorimetric experiments indicated that the discontinuous thickening iscaused by partial melting and recrystallization. The depression of transition temperature from the original crystal to the thicker one and the incompletion of reorganization with increase in 3HV unit can be attributed to the lowering of the interaction between the copolymer chain stems and to the difficulty in incorporation of the chains to crystal lattice, respectively.
Physical Properties, Structure Analysis and Enzymatic Degradation of Poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyvalerate]Films and Fibers Degradable Polymers and Materials - Principles and Practice,939:45-60 2006(Sep.) Author:T. Iwata, T. Tanaka, N. Adachi, M. Hasegawa, S. Teramachi, and Y. Doi Abstract:High tensile strength films and fibers of poly[(R)-3-hydroxybutyrate-co-8mol%-(R)-3-hydroxyvalerate]were prepared by cold-drawing from amorphous preforms at a temperature near the glass transition temeperature (Tg). High tensile fibers of over 1 GPa were processed by onestep-drawing with small crystal nuclei grown near Tg. Meltquenched films in a rubber state could be stretched reproducibly to a draw ratio of 16, and subsequent annealing under tension led to the improvement of the tensile strength and Young's modulus. The highly-ordered structure of films and fibers was investigated by wide- and small-angle X-ray diffractions in synchrotron radiation of SPring-8. The mechanical properties remained unchanged after storing for 6 months at room temperature, suggesting that a high crystallinity of the stretched-annealed films avoids a process of secondary crystallization. Cold-drawn films were enzymatically degraded with an extracellular PHB depolymerase purified from Ralstonia pickettii T1, and it was revealed that the stretched films had the shish-kebab structure.
Microbeam X-ray Diffraction and Enzymatic Degradation of Poly[(R)-3-hydroxybutyrate]Fibers with Two Kinds of Molecular Conformations Macromolecules,39:5789-5795 2006(Aug.) Author:T. Iwata, Y. Aoyagi, T. Tanaka, M. Fujita, A. Takeuchi, Y. Suzuki, and K. Uesugi Abstract:A new core-sheath structure constructed by two kinds of molecular conformations-2/1 helix (a-form) and planar zigzag (b-form) conformations-in biodegradable poly[(R)-3-hydroxybutyrate](P(3HB)) fiber was revealed by 0.5 m microbeam X-ray diffraction in synchrotron radiation. P(3HB) fiber processed by a method combining cold-drawing and two-step-drawing has both a-form and b-form molecular chains in the core region, while the sheath region consists of only a-form chains. The crystallinity and orientation of a-form crystals in the core region were higher than those in the sheath region. Microbeam X-ray diffraction during two-step-drawing of cold-drawn fiber at room temperature revealed the generation mechanism of this interesting core-sheath structure at the highly ordered structural level. The b-form in core region was generated from amorphous chains between a-form lamellar crystals by the strong stretching of two-step-drawing. However, in the sheath region, since the a-form lamellar crystals rotated along the two-step-drawing direction, molecular chains between lamellar crystals could not elongate sufficiently. The enzymatic degradation of P(3HB) fibers was performed with an extracellular poly(hydroxybutyrate) depolymerase purified from Ralstonia pickettii T1. The intensity of a reflection derived from the b-form decreased faster than that of the a-form in X-ray fiber diagram, despite the b-form existing in the core region. The enzymatic degradation progressed from (1) the amorphous chains between a-form lamellar crystals in the sheath region, (2) the b-form molecular chains in the core region, and (3) the a-form lamellar crystals in the whole fiber. The result that the rate of enzymatic erosion of the b-form was faster than that of the a-form indicates that the rate of enzymatic degradation can be controlled by the molecular conformation, despite the same chemical structure.
2D NMR Observation of Strain-Induced b-form in Poly[(R)-3-hydroxybutyrate] Macromolecules,39:4086-4092 2006(Jun.) Author:Y. Nishiyama, T. Tanaka, T. Yamazaki, and T. Iwata Abstract:The first NMR observation of the planar zigzag conformation (b-form) in a poly[(R)-3-hydroxybutyrate]uniaxially oriented film with high tensile strength is reported. A 13C two-dimensional (2D) off-magic-angle spinning NMR method which directly correlates the peak positions with the molecular orientation in uniaxially oriented samples was used. The 2D NMR spectra provide the 13C carbonyl signal of b-form separately from that of the 2/1 helixconformation (a-form). The orientations of the carbonyl carbons for a-form andb b-form were determind and compared to the previously proposed molecular models.
Formation of Highly Ordered Structure in Poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyvalerate]High-Strength Fibers Macromolecules,39:2940-2946 2006(Apr.) Author:T. Tanaka, M. Fujita, A. Takeuchi, Y. Suzuki, K. Uesugi, K. Ito, T. Fujisawa, Y. Doi, T. Iwata Abstract:Biodegradable fibers of poly[(R)-3-hydroxybutyrate-co-8%-(R)-3-hydroxyvalerate](P(3HB-co-8%-3HV)) produced from wild-type bacteria were prepared by melt-spinning, followed in an amorphous state by quenching near the glass transition temperature (Tg). High tensile strength fibers of over 1 GPa were prepared by one-step drawing with small crystal nuclei grown by isothermal crystallization near the Tg. This new drawing technique is a very attractive method for obtaining strong fibers from low-molecular-weight polyesters produced by wild-type bacteria. The highly ordered structure of strong P(3HB-co-8%-3HV) fibers was investigated by tensile measurement, scanning electron microscopy, and wide- and small-angle X-ray scatterings (WAXD and SAXS) with synchrotron radiation (SPring-8, Japan). The WAXD patterns of strong fibers showed sharp reflections corresponding to highly oriented a-form (21 helix conformation) and b-form (planar zigzag conformation). The weak reflections along the meridian in the SAXS patterns of strong fibers indicate that thedensity between a- and b-form crystals is nearly identical and that the fibers have highly oriented structure with various thicknesses of a-form lamellar crystals. Furthermore, the microbeam wide-angle X-ray diffraction with Fresnel zone plate optics in synchrotron radiation was performed to investigate the inner structure of the monofilament. It was revealed that strong P(3HB-co-8%-3HV) fibers have a uniform structure consistent with two types of molecular conformations: the a-form and b-form crystals. From the results of WAXD and SAXS patterns of one-step-drawn fibers after isothermal crystallization, a new mechanism for the development of b-form crystals is proposed as follows: Many small crystal nuclei in the amorphous region grow slowly during isothermal crystallization near the Tg. The b-form is produced during drawing by the stretching of molecular chains in the constrained amorphous region between small crystal nuclei which act as cross-linking points, and then the a-form lamellar crystals are generatedfrom small crystal nuclei by the crystallization during annealing.
Real-Time Synchrotron SAXS and WAXD Studies on Annealing Behavior of Poly[(R)-3-hydroxybutyrate]Single Crystals Macromolecules,39:2201-2208 2006(Mar.) Author:T. Sawayanagi, T. Tanaka, T. Iwata, H. Abe, Y. Doi, K. Ito, T. Fujisawa, and M. Fujita Abstract:Poly[(R)-3-hydroxybutyrate](P(3HB)) single crystals were grown isothermally at different crystallization temperatures (Tcs) in a dilute solution. Structural changes of the sedimented single-crystal mats on heating were followed by real-time synchrotron small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD) techniques, and the dependence of the annealing behavior on Tc was examined. The two-dimensional (2D) SAXS pattern clearly demonstrated that the P(3HB) single crystal exhibits a discontinuous increase in the lamellar thickness at an annealing temperature. The onset of the discontinuous thickening depended on Tc or the initial lamellar thickness. The discontinuous thickening occurred at higher temperature as the initial lamellar thickness increased. In the transition region where the discontinuous thickening progressed, the new scattering peak intensity increased while the original one decreased. On the other hand, the crystallinity, estimated from the 2D WAXD patterns, first decreased and then recovered. The lamellar thickening was accompanied by endo- and exothermic signals in differential scanning calorimetry. Accordingly, the discontinuous lamellarthickening is caused by partial melting and recrystallization. The degree of recovery in crystallinity fell with increasing initial lamellar thickness. This is most probably because the crystallization rate becomes slower with increasing temperature in thetransition region. After the transition, the long period between the reorganized lamellae increased, while the crystallinity decreased and, finally, diminished due to complete melting.
Uniaxial Drawing of Poly[(R)-3-hydroxybutyrate]/Cellulose Acetate Butyrate Blends and Their Orientation Behavior Macromolecular Bioscience,5:840-852 2005(Sep.) Author:J. W. Park, T. Tanaka, Y. Doi, and T. Iwata Abstract:Miscible blends of PHB and CAB were prepared by the solvent-casting method with various blend compositions, and their orientation behavior was investigated during uniaxial drawing. X-ray analysis revealed that the orientation of the crystallizable PHB component in the drawn PHB/CAB blends was changed from c-axis-orientation to a-axis-orientation with increasing CAB content. The a-axis-orientation was a result from the a-axis-oriented crystal growth caused by the intramolecular nucleation and the confined crystal growth. For quantitative assessment of the chain orientation, the Hermans orientation functions of thetwo respective components were obtained from the polarized FT-IR measurements. The orientation function of pure PHB stretched to 5 times of its initial length was approximately 0.8. However the value decreased rapidly with increasing CAB content, and it turned to a negative value from 30 wt.-% CAB content. This indicates that the PHB chains were aligned perpendicular to the drawing direction. On the contrary, the value of the CAB component remained almost unchanged at about 0.1 regardless of the blend composition and the annealing time, indicating that the CAB chains were constantly oriented parallel to the drawing direction without any chain relaxation. In addition, SAXS analysis suggested that the lamellar stacking direction also changed from parallel to perpendicular in the stretching direction with increasing CAB content. Keywords:blends, cellulose acetate butyrate, orientation, poly[(R)-3-hydroxybutyrate], uniaxial drawing
Structure investigation of narrow banded spherulites in polyhydroxyalkanoates by microbeam X-ray diffraction with synchrotron radiation Polymer,46:5673-5679 2005(Jul.) Author:T. Tanaka, M. Fujita, A. Takeuchi, Y. Suzuki, K. Uesugi, Y. Doi, and T. Iwata Abstract:Narrow banded structures of spherulites of poly[(R)-3-hydroxybutyrate](P(3HB)) and its copolymers, with different second monomer unit of 4-hydroxybutyrate, 3-hydroxyhexanoate or 6-hydroxyhexanoate, were investigated by microbeam X-ray diffraction with Fresnel Zone Plate technique in synchrotron radiation (SPring-8). Radial scanning of spherulites were performed in 2 or 4?μm steps with 0.5?μm beam diameter of fine microfocus beam. The X-ray diffraction patterns for P(3HB) homopolymer spherulites showed the change of crystal orientation along the radial direction (a-axis), while the b- and c-axes rotated around a-axis. The intensities in microbeam X-ray diagrams of spherulites for P(3HB) copolymers changed periodically as function of the distance along the radial direction. The periodicity measured by X-ray diffraction was matched with narrow band spacing (15-25?μm) observed by polarized optical microscopy. Keywords:Biodegradable polymer; Poly[(R)-3-hydroxybutyrate]copolymers; Banded spherulites
Synchrotron SAXS and WAXS Studies on Changes in Structural and Thermal Properties of Poly[(R)-3-hydroxybutyrate]Single Crystals during Heating Macromol. Rapid Commun.,26(9):678-683 2005(May) Author:M. Fujita, T. Sawayanagi, T. Tanaka, T. Iwata, H. Abe, Y. Doi, K. Ito, and T. Fujisawa Abstract:The annealing and melting behavior of poly[(R)-3-hydroxybutyrate](P(3HB)) single crystals were followed in real time by synchrotron small- (SAXS) and wide-angle X-ray scattering (WAXS) measurements. The real-time SAXS measurements revealed that the P(3HB) single crystal exhibits a discontinuous increase of lamellar thickness during heating. The structural changes as observed by SAXS and WAXS were in response to the thermal properties of single crystals characterized by differential scanning calorimetry. Keywords:annealing, poly[(R)-3-hydroxybutyrate], SAXS, single crystal, WAXS
Nonlinear optical transmission of silk/green fluorescent protein (GFP) films Polymer,45:8451-8457 2004(Nov.) Author:S. Putthanarat, R.K. Eby, R.R. Naik, S.B. Juhl, M.A. Walker, E. Peterman, S. Ristich, J. Magoshi, T. Tanaka, M.O. Stone, B.L. Farmer, C. Brewer, and D. Ott Abstract:In this initial work, we demonstrate a technique for preparing thin (10-20?μm) films of silk doped with green fluorescent protein (GFP) by casting/annealing at 20?°C and describe the resulting film characteristics. Notably, the GFP molecules maintain their nonlinear optical properties as evidenced by two-photon fluorescence microscopy and two-photon absorption measurements using near-infrared femtosecond pulses. The fractional transmission of focused near-infrared pulses of 775?nm wavelength, 140?fs pulsewidth was observed to decrease as the incident pulse energy is increased and/or the incident spot size is decreased, indicating that nonlinear absorption is taking place. Visible damagefrom the pulses is observed in a 10?μm film at the highest peak incident fluences, which were in the range of 0.1-0.2?J/cm2. Variations in thickness, morphology and GFP concentration of the films make precise specification of the two-photon absorption coefficient difficult. Since these films have potential applications in photonics, we suggest techniques forimproving these properties in future generations of films. The suggestions present opportunities for future work. Keywords:Silk films; GFP; Nonlinear transmission
微生物産生生分解性脂肪族ポリエステルの高強度繊維?ポリヒドロキシアルカン酸繊維の延伸・熱処理条件について? SEN'I GAKKAISHI,60(11):309-315 2004(Nov.) Author:田中稔久、青柳佳宏、土肥義治、岩田忠久 Abstract:Strong fibers of ultra-high-molecules-weight poly[(R)-3-hydroxybutyrate](UHMW-P(3HB)) produced by a recombinant Escherichia coli strainand poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyvalerate](P(3HB-co-8%-3HV)) by wild-type bacteria were prepared from amorphous states by cold-drawing and two-step-drawing. The annealing procedure was performed during two-step-drawing (simultaneous method), or after two-step-drawing (successive method). The tensile strength of UHMW-P(3HB) fiber prepared by the successive method was higher than that prepared by the simultaneous method. Bacterial P(3HB-co-8%-3HV) fibers with high tensile strength were processed by cold-drawing and two-step-drawing with successive annealing procedures. Furthermore, P(3HB-co-8%-3HV) fibers were prepared by one-step-drawing after the formation of small nuclei by isothermal crystallization near the Tg. It was revealed that multi-step-drawing and one-step-drawing after isothermal crystallization were very useful to obtain high strength fibers of both P(3HB) homo and copolymers.
Nanostructure of Natural Fibrous Protein: In Vitro Nanofabric Formation of Samia Cynthia ricini Wild Silk Fibroin by Self Assembling Nano Letters,3:1329-1332 2003(Oct.) Author:S.-i. Inoue, H. Tsuda, T. Tanaka, M. Kobayashi, Y. Magoshi, and J. Magoshi Abstract:Atomic force microscopy was adopted to study the nanoscopic structure formation of natural fibrous protein, fibroin from the Samia cynthia ricini wild silkworm. We have observed highly ordered nanoscale textile-fabric-like structures of fibroin molecules. From AFM and SDS-PAGE experiments, it was revealed that fibroin molecules have a rigid rodlike structure and form aggregates by end-to-end interactions ofmolecules. By analogy with Bombyx mori fibroin, S. c. ricini fibroin is supposed to assemble by electrostatic interactions of molecules.
Textile-Fabric-Like Nanostructure Formation of Silk Protein by Self Assembling Transactions of the Materials Research Society of Japan,28(3):541-544 2003(Sep.) Author:S.-I. Inoue, H. Tsuda, T. Tanaka, M. Kobayashi, Y. Magoshi, and J. Magoshi Abstract:We have observed highly ordered nanoscale textile-fabric-like structure of natural fibrous protein, fibroin obtained from wild silkworm, Samia cynthia ricini (Eri silkworm) by Atomic Force Microscopy (AFM). It was also revealed that S. c. ricini fibroin molecules have rigid rodlike form. SDS-PAGE analysis showed that the S. c. ricini fibroin is a homodimer of 160kDa protein linked by a disulfide bond. The length and the diameter of observed rodlike molecules are in good agreement with the size estimated from the molecular weight. The AFM images also shows that molecules assemble in end-to-end fashion to form higher order structure. As there are many similaities between Bombyx mori silk fibroin and S. c. ricini silk fibroin, the structure formation mechanism is considered to be similar to that of B. mori silk fibroin, which assembles by electrostatic interaction of charged amino acid residues located on both ends of a molecule. Keywords:silk fibroin, protein, AFM, nanostructure, self-assemble
カイコの液状絹の熱分析?家蚕、セリシン蚕および野蚕の液状絹について 熱測定、Netsu Sokutei,30(3):111-115 2003(Jun.) Author:田中稔久、馬越芳子、馬越淳 Abstract:The thermal properties of liquid silk obtained from the domesticated silkworm (Bombyx mori), the mutant domesticated silkworm (Sericin cocoon silkworm, Nd-s), and four wild silkworms (Samia cynthia ricini, Dictyoploca japonica, Antheraea pernyi and Antheraea yamamai) were investigated by differential scanning calorimetry (DSC).The weak endothermic peak in the DSC curves for the liquid silk of the domestic silkworm corresponded to the breaking of hydrogen bonds in the a-form of fibroin. The process of crystallization of the liquid silk differed between domestic and wild silkworm. The starting temperature of transition for the liquid silk of the domestic silkworm was calculated.
Uptake of atmospheric carbon dioxide into silk fiber by silkworms Biomacromolecules,4:778-782 2003(Mar.) Author:J. Magoshi, T. Tanaka, H. Sasaki,M. Kobayashi, Y. Magoshi, H. Tsuda, M. A. Becker, S.-I. Inoue, and K. Ishimaru Abstract:The relation between the uptake of atmospheric CO2 and insect's production of silk fiber has not yet been reported. Here, we provide the first quantitative demonstrations that fourspecies of silkworms (Bombyx mori, Samia cynthia ricini, Antheraea pernyi, and Antheraea yamamai) and a silk-producing spider (Nephila clavata) incorporate atmospheric CO2 into their silk fibers. The abundance of 13C incorporated from the environment was determined by mass spectrometry and 13C NMR measurements. Atmospheric CO2 was incorporated into the silk fibers in the carbonyl groups of alanine, aspartic acid, serine, and glycine and the C of aspartic acid. We show a simple model for the uptake ofatmospheric CO2 by silkworms. These results will demonstrate that silkworm has incorporated atmospheric CO2 into silk fiber via the TCA cycle; however, the magnitude of uptake into the silk fibers is smaller than that consumed by the photosynthesis in trees and coral reefs.
Biospinning: change of water contents in drawn silk Journal of Polymer Science: Part B: Polymer Physics,41:274-280 2003(Feb.) Author:T.Tanaka, M.Kobayashi, S.-I. Inoue, H. Tsuda, J. Magoshi Abstract:Changes of the water content in drawn silk during drying were investigated by thermal analysis and 1H pulse NMR. Water in liquid silk by drawing extruded from the inside of the silk filament into ambient air. The water contents in the drawn silk decreased with drying time. Assuming the nonfreezing water has a concentration of 10 wt % in the liquid silk, the percentage distribution of water in liquid silk is composed of 10 wt % nonfreezing water, 40 wt %freezing water, and 30 wt % free water. This 40 wt % freezing water in the liquid silk may be important for the formation of fine pores on the surface of drawn silk. The apparent pore radius, which was calculated from the results of thermal analysis, on the surface of drawn silk decreased to 5.0 nm and finally to 2.0 nm. The calculated apparent fine pore formed on the surface by drawing was 4.0 nm. Keywords:biopolymer, drawing, differential scanning calorimetry (DSC), 1H pulse NMR
Thermal properties of Bombyx mori and several wild silkworm silks Journal of Thermal Analysis and Calorimetry,70:825-832 2002(Oct.) Author:T. Tanaka, J. Magoshi, Y. Magoshi, S.-I. Inoue, M. Kobayashi, H. Tsuda, M. A. Becker, and Sh. Nakamura Abstract:The thermal properties of liquid silk from domestic and wild silkworms are investigated. Liquid silks obtained from the silk gland of thedomesticated silkworm, Bombyx mori and four wild silkworms, Samia cynthia ricini, Dictyoploca japonica, Antheraea pernyi and Antheraea yamamai were used. The DSC curves for the liquid silk from the domestic silkworm have weak endothermic peaks corresponding to the breaking of hydrogen bonds in the -form or to the untangling of physical network. The DSC curves for the wild silkworm silks, however, show clear exothermic peaks corresponding to a phase transition from the -helix conformation to the -form. Liquid silk from all the different silkworms undergoes a characteristic irreversible phase transition. Keywords:phase transition, wild silkworm, domestic silkworm, liquid silk
Control of Gel-Sol transition of silk fibroin by metal ions Transactions of the Materials Research Society of Japan,26(2):577-579 2001(Dec.) Author:M. Kobayashi, T. Tanaka, S.-i. Inoue, H. Tsuda, J. Magoshi, and Y. Magoshi Abstract:In silk glands of the silkworm, Bombyx mori, the gel-sol transition of silk fibroin occure. At the anterior part in middle division (MA) of silk gland, the silk fibroin undergoes gel-sol transition. In order to elucidate the mechanism of this transition, thequantity of metal ions in each part of silk glands was measured by using an element analyzer. It was found that in MA region the amount of Ca2+ ions decreased and K+ ions increased. We carried out dynamic viscoelastic measurements of silk fibroin aqueous solution (0.214 wt%) with various [Ca2+]. The result indicates that in the low calcium concentration region (0-0.5 mM) storage modulus G' and loss modulus G'' of silk fibroin solution increased with increase in [Ca2+]. Furthermore, values of G' and G'' were almost independent of angular frequency w. This experimental result means that some elastic network exists in silk fibroin solution and calcium ions stabilizes this network structure. It could be concluded that physical cross-links are formed by calcium ion and the gel-sol transition is induced by metal ions. Keywords:silk fibroin, gel, transition, calcium, potassium
Structure and properties of poly(vinyl alcohol)/k-carrageenan blends Polymer International,50(10):1103-1108 2001(Oct.) Author:T. Tanaka, T. Lu, S. Yuasa, and K. Yamaura Abstract:Blends of a commercial atactic poly(vinyl alcohol) (a-PVA) derived from vinyl acetate and k-carrageenan were prepared by mixing the aqueous solutions of both samples. Blend films prepared by casting were transparent. In the DSC curves of the blend films, the endothermic peaks shifted to lower temperature with an increase of the content of k-carrageenan. The Young's modulus and the strength at break increased with an increase of the content of a-PVA. As the standing temperature of the blend solutions decreased, the gelation region increased also at high content of carrageenan. In the amorphous regions of blend films, a-PVA and k-carrageenan were miscible. Keywords:poly(vinyl alcohol); k-carrageenan; blend solutions; gelation; blendcasting films; miscible; thermal properties; mechanical properties
Spherulites of Tussah silk fibroin: structure, thermal properties and growth rates Journal of Thermal Analysis and Calorimetry,64:645-650 2001(May) Author:T. Tanaka, J. Magoshi, Y. Magoshi, B. Lotz, S.-I. Inoue, M. Kobayashi, H. Tsuda, M. A. Becker, Zh. Han and Sh. Nakamura Abstract:The crystal structure, thermal properties and growth rates of spherulites of the Tussah silk fibroin, produced upon drying ofthe silk taken directly from the lumen which is essentially a poly(L-alanine)polypeptide, are investigated. Depending on casting conditions, spherulites with either a helical chain conformation or b parallel sheet structure are produced. The growth ratesdisplay a strong positive temperature coefficient, with an apparent transition, which howevercannot be related with the formation of two different crystal structures at this stage. Keywords:growth rate, silk, spherulite, structure, thermal property, Tussah silk fibroin
Crystallization of silk fibroin from solution Thermochimica Acta,352-353:165-169 2000(Jul.) Author:J. Magoshi, Y. Magoshi, M. A. Becker, M. Kato, Z. Han, T. Tanaka, S.-i. Inoue, and S. Nakamura Abstract:X-ray diffraction and differential scanning calorimetry (DSC) were carried out to clarify the crystallization mechanism of silk fibroin from liquid silk (native silk fibroin solution). In the course of the evaporation of water from liquid silk, silk fibroin crystallizes when weight loss of water reaches 40% at the temperatures below 120°C. The crystallization occurs 20?min after the specimens are put at above 100°C and 1-3?h at below 100°C.In the DSC curve of liquid silk of domestic silk Bombyx mori, the αミβ transition occurs at 51°C. The crystallization temperatures of wild silk Antheraea yamamai, Antheraea pernyi and Dictyoploa japonica are 59, 67 and 62.5°C, respectively. The exothermic DSCpeaks at these temperatures are attributed to the conformational change to the β-form. Keywords:Silk fibroin; DSC; Crystallization; α- to β-form transition; Wild silk
Atomic force microscopy: Bombyx morisilk fibroin molecules and their higher order structure Journal of Polymer Science: Part B: Polymer Physics,38:1436-1439 2000(Jun.) Author:S.-i. Inoue, J. Magoshi, T. Tanaka, Y. Magoshi, and M. Becker Abstract:We performed atomic force microscopy measurements on fibroin molecules from the domestic silkworm, Bombyx mori. At low concentrations, we could observe single protein molecules. The shape of the observed molecules is a rod with long smaller chains extending from the ends. The size of the rod is 60 nm in length and 15 nm in width. At high concentrations, we observed long threadlike aggregates of fibroin molecules, their chains entangled with one another. These results provide insight into the microscopic mechanism of silk-fiber formation. Keywords:silk;fibroin; AFM; higher order structure
Effect of addition of saccharides on gelation of aqueous poly (vinyl alcohol) solutions Journal of Applied Polymer Science,74(5):1298-1303 1999(Oct.) Author:K. Yamaura, M. Fukuda, T. Tanaka, and T. Tanigami Abstract:The properties of poly(vinyl alcohol) (PVA) hydrogels containing saccharides (D-xylose, D-fructose, D-glucose, and maltose) were examined.The effect of the addition of saccharides to PVA hydrogels on their melting temperatures was remarkable when the gels were chilled at 0ーC with saccharide contents above 40 g/dL. Particularly, the melting temperature was the highest for PVA hydrogels with glucose and above 73ーC at the polymer concentrations above 6 g/dL. Namely, the enthalpy of the thermal dissociation of the junctions of the spatial network H was the highest of the four saccharides (glucose>fructose>maltose>xylose) and 150 kJ/mol for the hydrogels with the glucose content of 60 g/dL. The uniform preservation of saccharides and water in their gels were the highest for the gels with fructose during standing for a long time in air after freeze-drying. Keywords:poly(vinyl alcohol); saccharides; mixed solution; gelation; dynamic modulus; syneresis
Phase separation in poly(vinyl alcohol)/gelatin blend systems Polymer International,48(9):811-818 1999(Sep.) Author:T. Tanaka, S. Ohnishi, and K. Yamaura Abstract:Blends of a commercial poly(vinyl alcohol) (a-PVA) derived from vinyl acetate and gelatin obtained from collagen were prepared by mixing aqueous solutions of both samples under various conditions. For the blend hydrogels, the depression of melting temperatures was observed at high PVA content. Similarly to the a-PVA/silk fibroin (SF) system, when the degrees of polymerization of PVA increased, the microphase separation region in a phase diagram of the blend films increased for the a-PVA/gelatin system. In the IR spectra of the blend films, no absorption bands corresponding to a conformational change of gelatin appeared. Comparison of the mechanical properties of the a-PVA/gelatin and a-PVA/SF systems, showed the interaction between PVA and gelatin molecules to be smaller than that between PVA and SF molecules. Keywords:poly(vinyl alcohol); gelatin; blends; phase separation; phase diagram; interaction; coacervation
Phase separation structure in poly(vinyl alcohol)/silk fibroin blend films Polymer International,45(2):175-184 1998(Feb.) Author:T. Tanaka, T. Tanigami, and K. Yamaura Abstract:Blend films of a commercial poly(vinyl alcohol) (a-PVA) derived from vinyl acetate and silk fibroin (SF) obtained from degummed silk were prepared by mixing the aqueous solutions of both samples. A plain weave structure was recognized only in the blend films, whereas no structure was found for the superimposed films of both samples. The phase separation structure of the blend films was examined by microscopic observations elongation, tensile tests, and IR measurements. The microphase separation region increased with increase in the degree of polymerization of the PVA. In the IR spectra of the blend films with high PVA contents cast under certain conditions, the absorption peak attributed to the cross--form conformation of SF appeared strongly. Gelatin, a water-soluble and natural polymer, was also used for comparison with SF. The ternary phase diagram in an a-PVA/gelatin/H2O system was obtained experimentally and the critical point was used to estimate the interaction parameter between PVA and gelatin molecules. The phase separation structure and the interaction between PVA and SF molecules were also discussed taking into consideration the results of the a-PVA/gelatin system. Keywords:poly(vinyl alcohol); silk fibroin; gelatin; blend films; phase separation; phase diagram; interaction
Properties of silk fibroin/poly(vinyl alcohol) blend solutions and peculiarstructure found in heterogeneous blend films Polymer International,42(1):107-111 1997(Jan.) Author:T. Tanaka, M. Suzuki, N. Kuranuki, T. Tanigami, and K. Yamaura Abstract:The gelation of aqueous poly(vinyl alcohol) (PVA) solution was accelerated by addition of a small amount of silk ・broin (SF). The peculiar structure found in heterogeneous SF/PVA blend ・lms was analysed by polarizing microcopy, differential scanning calorimetry (DSC), infrared spectroscopy (IR), and scanning electron microscopy (SEM). The blend flms (over 30 km thick) of SF/PVA (90/10 to 60/40 weight ratio) separated macroscopically into two phases: SF-rich and PVA-rich. SF-rich phases had many spherical particles (1-25 μm). In the PVA-rich phases, a fabric-like plain weave structure was found microscopically under a dark field. The SF-rich and PVA-rich phased were analysed by DSC, IR, SEM. The phase separation is also discussed. Keywords:silk fibroin, poly(vinyl alcohol), blend, gelation, films, phase separation, dark field, fabric-like structure
講演・口頭発表等 Effect of Natural Antibacterial Product on P(3HB-co-3HH) Nanofibers Composite The 16th Pacific Polymer Conference 2019(Dec.) Presenter:Rina Afiani Rebia, Toshihisa Tanaka
Preparation of Biodegradable Multilayer Composite from Zein Nanofiber /PHBH films 14th International Conference on Materials Chemistry (MC14) 2019(Jul. 09) Presenter:Naruebet Aim-I, Yoshihisa Sakamoto, Toshihisa Tanaka
STRUCTURAL ANALYSIS OF BIODEGRADABLE POLYESTER COPOLYMER FILMS AND FIBERSBY STRETCHING ON COLD CRYSTALLIZATION 47th IUPAC World Chemistry Congress(IUPAC Paris 2019) 2019(Jul.) Presenter:Toshihisa Tanaka
Additive of natural product into biodegradable polymer P(3HB-co-3HH) fiber 6th International Conference on Multifunctional, Hybrid and Nanomaterials 2019 2019(Mar. 12) Presenter:Rina Afiani Rebia, Toshihisa Tanaka
Fabrication of biodegradable polymer Zein/P(3HB-co-3HH) multilayer composite 6th International Conference on Multifunctional, Hybrid and Nanomaterials 2019 2019(Mar. 11) Presenter:Naruebet Aim-I, Yoshihisa Sakamoto, Toshihisa Tanaka
Morphology of P(3HB-co-3HH) Fiber and Nanofiberwith Propolis as an Antibacterial Agent Textile Summit 2018 2018(Sep. 21) Presenter:Rina Afiani Rebia, Toshihisa Tanaka
Preparation and Physical Properties of Silicone Modified Polyurethane Nanofibers with Different Molecular Structures Textile Summit 2018 2018(Sep. 21) Presenter:Chuan Yin, Rino Okamoto, Mikihisa Kondo, Toshihisa Tanaka,Hatsuhiko Hattori, Masaki Tanaka, Hiromasa Sato, Shouta Iino
Preparation of PHBH Nanofibers with Centella asiaticaand Emu Oil as Antibacterial Agent Textile Summit 2018 2018(Sep. 21) Presenter:Nurul Shaheera Binti Sadon, Rina Afiani Rebia, Toshihisa Tanaka
BIODEGRADABLE POLYESTER P(3HB-CO-3HH) NANOFIBERSWITH NATURAL PRODUCT AS ANTIBACTERIAL REAGENT 10th International Conference of Modification, Degradation and Stabilization of Polymers(MoDeSt2018) 2018(Sep. 04) Presenter:Rina Afiani Rebia, Nurul Shaheera binti Sadon, Toshihisa Tanaka
FABRICATION AND PHYSICAL ANALYSIS OFSILICONE MODIFIED POLYURETHANE NANOFIBERS 10th International Conference of Modification, Degradation and Stabilization of Polymers(MoDeSt2018) 2018(Sep. 03) Presenter:Chuan Yin, Rino Okamoto, Mikihisa Kondo, Toshihisa Tanaka,Hatsuhiko Hattori, Masaki Tanaka, Hiromasa Sato, Shouta Iino
PHYSICAL PROPERTIES AND COMPARISON OF FILMS AND GELS FOR POLYVINYL ALCOHOL / BACTERIAL CELLULOSE BLENDS 10th International Conference of Modification, Degradation and Stabilization of Polymers(MoDeSt2018) 2018(Sep. 03) Presenter:Toshihisa Tanaka, Masanori Sugiura, Daisuke Yamashita,Masuhiro Tsukada, Hiroya Watanabe
Preparation of Silicone-modified Polyurethane Nanofibers by Electrospinning 4th International Nanofiber Symposium 2015(Oct. 15) Presenter:Hatsuhiko Hattori, Masaki Tanaka, Rino Okamoto, Toshihisa Tanaka, Hiromasa Sato, Shouta Iino,Yoshitaka Koshiro
Structural analysis of biodegradable polyester films prepared by aging on cold crystallization temperature and by soaking solvent effect 5th International Conference on Biobased and Biodegradable Polymers 2015(Oct. 07) Presenter:Toshihisa Tanaka, Yumiko Takayama, Motomu Nishijo, Keigo Matsukawa, Tadahisa Iwata
Structural analysis of biodegradable polyester Poly[(R)-3-hydroxybutyrate]copolymer fibers and films prepared by aging on cold crystallization Green Chemistry 2011, 3rd Asia-Oceania Conference on Green&Sustainable Chemistry 2011 Presenter:T. Tanaka, Y. Takayama, M. Nishijo, K. Nakai, and T. Iwata
Analysis of biodegradable polyester Poly[(R)-3-hydroxybutyrate]copolymer fibers and films stretched after isothermal crystallization 12th Pacific Polymer Conference 2011 Presenter:Toshihisa Tanaka, Yumiko Takayama, Kaoru Nakai, and Tadahisa Iwata
Drug-impregnation in porous fibers of microbial poly[(R)-3-hydroxybutyrate-co-4-hydroxybutyrate]by one-step drawing method with small crystal nuclei Pacifichem 2010 2010 Presenter:Chizuru Hongo, Hiroyuki Ichino, Toshihisa Tanaka, Kazuki Ito, Kentaro Uesugi, Akihisa Takeuchi, Yoshio Suzuki, and Tadahisa Iwata
Preparation, structure analysis and enzymatic degradation of poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate] Pacifichem 2010 2010 Presenter:Taizo Kabe, Toshihisa Tanaka, Kenichi Kasuya, Kazuki Ito, Akio Takemura, and Tadahisa Iwata
Analysis of high-strength biodegradable polyester Poly[(R)-3-hydroxybutyrate]copolymer fibers by X-ray tomography and enzymatic degradation Pacifichem 2010 2010 Presenter:Toshihisa Tanaka, Akihisa Takeuchi, Yoshio Suzuki, Kentaro Uesugi, and Tadahisa Iwata
Analysis of high-strength biodegradable fibers streched after isothermal crystallization using synchrotron radiation International symposium on biological polyesters (ISBP 2008) 2008(Nov.) Presenter:Tanaka Toshihisa, Iwata Tadahisa
Characteristics of Activated Carbon Fiber Turning on Electricity 4th International Conference on Advanced Fiber/Textile Materials 2007 in Ueda (ICAFTM2007) 2007 Presenter:I. Yamaura, H. Sakai, K. Tanaka
New Core-Sheath Structure of Poly[(R)-3-hydroxybutyrate]Fibers Revealed by Micro-beam X-ray Diffraction SPring-8 Research Frontiers 2005,:80-81 2006(Aug.) Author:T. Iwata, T. Tanaka Abstract:本書は、生分解性脂肪族ポリエステルであるポリ[(R)-3-ヒドロキシブチレート]を用いて、冷延伸・二段階延伸法によって作製した高強度繊維の高次構造解析について報告したものである。