Tatsuo Kaneko

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Organization: Japan Advanced Institute of Science and Technology , Japan

Department: School of Materials Science

Title: Associate Professor(PhD)

TOPICS

Material Chemistry

Polymer

Polyimide Stimuli Responsive Polymers Stimuli Responsive Polymers Photo Responsive Polymers Polysulfone

Chemicals
References

Tough and Porous Hydrogels Prepared by Simple Lyophilization of LC Gels

Co-reporter:Saranyoo Sornkamnerd, Maiko K. Okajima, and Tatsuo Kaneko

ACS Omega August 2017? Volume 2(Issue 8) pp:5304-5304

Publication Date(Web):August 31, 2017

DOI:10.1021/acsomega.7b00602

Porous hydrogels possessing mechanical toughness were prepared from sacran, a supergiant liquid crystalline (LC) polysaccharide produced from Aphanothece sacrum. First, layered hydrogels were prepared by thermal cross-linking of film cast over a sacran LC solution. Then, anisotropic pores were constructed using a freeze-drying technique on the water-swollen layered hydrogels. Scanning electron microscopic observation revealed that pores were observable only on the side faces of sponge materials parallel to the layered structure but never on the top or bottom faces. The pore size, porosity, and swelling behavior were controlled by the thermal-cross-linking temperature. To clarify the freezing effect, a freeze–thawing method was used for comparison. The freeze–thawed hydrogels also formed layers but no pores. The mechanical properties and network structures of hydrogels were also studied, clarifying that porous hydrogels, even those with a high quantity of pores, were tough owing to the pores orienting along the layer direction like tunnels.Topics: Hydrogels; Hydrogels; Liquid crystals; Mechanical properties; Polysaccharides;

Synthesis of thermotropic polybenzoxazole using 3-amino-4-hydroxybenzoic acid

Co-reporter:Mohammad Asif Ali;Hiroshi Shimosegawa;Aniruddha Nag

Journal of Polymer Research 2017 Volume 24( Issue 12) pp:214

Publication Date(Web):15 November 2017

DOI:10.1007/s10965-017-1362-9

Bio-based polybenzoxazoles (PBOs) are prepared by polycondensation of diacid monomer derived from 3-amino-4-hydroxybenzoic acid with a series of aliphatic diamines. Resulting bio-based PBOs have high weight average molecular weight ranging 5.70–7.20 × 104 g/mol and show ultrahigh thermal resistance with T10 values over 400 °C and Tg values over 170 °C, which are higher than those of conventional bio-based polymers, polyamides 11 (around 60 °C) or poly(lactic acid) (56 °C). Especially hydrazide group of the bio-based PBO were cyclized to form diazole ring by annealing at 330 °C for 20 min. The resultant PBO show liquid crystalline (LC) behavior to spin fiber in a melting state. The resultant PBO fibers showed high values of Young’s modulus and mechanical strength as compared with conventional polymers polyamide 11 and poly(lactic acid) (PLA).

Directional control of diffusion and swelling in megamolecular polysaccharide hydrogels

Co-reporter:G. Joshi, K. Okeyoshi, M. K. Okajima and T. Kaneko

Soft Matter 2016 vol. 12(Issue 25) pp:5515-5518

Publication Date(Web):17 May 2016

DOI:10.1039/C6SM00971A

Directional control of diffusion and swelling in megamolecular polysaccharide hydrogels is demonstrated by focusing on the anisotropic structures for water absorption. Due to the presence of a layered structure in the hydrogel, the directional control for diffusion parallel to the planar direction and swelling in the lateral direction are possible.

Preparation of a Ductile Biopolyimide Film by Copolymerization

Co-reporter:Hojoon Shin, Siqian Wang, Seiji Tateyama, Daisaku Kaneko, and Tatsuo Kaneko

Industrial & Engineering Chemistry Research 2016 Volume 55(Issue 32) pp:8761

Publication Date(Web):July 26, 2016

DOI:10.1021/acs.iecr.6b02221

We developed ductile biopolyimide (BPI) films derived from a renewable aromatic diamine, 4,4′-diaminotruxillic acid, with a mixture of two different dianhydrides. The BPI copolymers show high thermal resistance with T10 values of over 406 °C and Tg values of over 208 °C, improved tensile strength and elongation at break, and a Young’s modulus maintained at around 4 GPa. In addition, the copolymers showed an adhesion strength to the carbon plate of 0.22–4.47 MPa, which is similar to that of cyanoacrylate superglue. In summary, we develop tough films composed of the copolymers derived from benzophenonetetracarboxylic dianhydride and oxydiphthalic dianhydride. The film shows a strain energy as high as that of a commercial Kapton film. We confirm the ductility of the film by microscopy and tensile testing after it was completely folded.

Fermentation of aromatic lactate monomer and its polymerization to produce highly thermoresistant bioplastics

Co-reporter:Hieu Duc Nguyen, Tatsuo Kaneko, Naoki Takaya, Tomoya Fujita and Takashi Ito

Polymer Journal 2016 48(1) pp:81-89

Publication Date(Web):September 30, 2015

DOI:10.1038/pj.2015.80

A microbial fermentation system was designed to convert glucose to 4-hydroxyphenyllactic acid (DHPA), which is an aromatic-containing derivative of lactic acid. By methylation, DHPA was transformed to a diol monomer for synthesis of bio-based polyesters with benzene rings in their backbone. The polycondensation of the DHPA diol was performed with a series of aliphatic diacid chlorides to produce semi-aromatic polyesters with glass-transition temperatures <45 °C. By polycondensation with aromatic diacylchlorides, such as terephthaloyl chloride and isophthaloyl chloride, thermally stable DHPA-based polyesters with glass-transition temperatures as high as 130 °C were obtained.

Ultrahigh performance bio-based polyimides from 4,4′-diaminostilbene

Co-reporter:Amit Kumar, Seiji Tateyama, Katsuaki Yasaki, Mohammad Asif Ali, Naoki Takaya, Rajeev Singh, Tatsuo Kaneko

Polymer 2016 Volume 83() pp:182-189

Publication Date(Web):28 January 2016

DOI:10.1016/j.polymer.2015.12.008

•Novel synthetic route for the synthesis of aromatic diamines from biomass based material were developed.•Novel Semi and fully bio-based polyimides were prepared and characterized.•Ultrahigh tensile strength polyimide was developed.We have developed a novel route for the synthesis of high-performance bio-polyimides (PIs) microbially-derived from photo-responsive aromatic diamine 4,4′-diaminostilbene (DAS) and its reduced counterpart 4, 4′-(ethane-1,2-diyl)dianiline (EDDA). DAS and EDDA were condensed with various commercially-available dianhydrides to obtain a series of poly(amic acid)s (PAAs) and PIs which were characterized in terms of their thermal, mechanical, and photo-functions. These bio-based PAAs showed a very high viscosity of 6.62 dL/g, and the PIs showed ultrahigh thermal resistance with Td10 values over 600 °C, which were higher than that of any bio-based plastic reported thus far. They also showed Tg values above 250 °C, and tensile strength of over 132 MPa, which is higher than that of Kapton™. The PIs also showed photo-functional behavior based on stilbene-based photoreactions.

Ultrahigh Heat-resistant, Transparent Bioplastics from Exotic Amino Acid

Co-reporter:Tatsuo Kaneko, Seiji Tateyam, Maiko Okajima, Shin Hojoon, Naoki Takaya

Materials Today: Proceedings 2016 Volume 3(Supplement 1) pp:S21-S29

Publication Date(Web):2016

DOI:10.1016/j.matpr.2016.01.004

Most cinnamate derivatives were biosynthesized via sikimate pathway in plants and bacteria, and the cinnamates were used as renewable starting materials for high-performance polyesters. p-hydroxycinnamic acid (4HCA), ferulic acid (MHCA), caffeic acid (DHCA), 4-aminocinnamic acid (4ACA) were selected as bioresources. As a result of investigating the structure-property relationships of polyesters from these hydroxyacids, we found that poly(4HCA-co-DHCA)s showed high mechanical strength, high Young's modulus, and high softening temperature. However thermal degradation temperature of the polyesters was limited to around 300 oC, which restricts the application. Then we used an exotic amino acid, 4ACA, which was bioavailable by microorganism engineering. The photodimer of 4ACA was used as a bio-based monomers for aromatic polyamides and polyimides. Especially the polyimides derived from the photodimer and cyclobutanetetracarboxylic dianhydrides showed a good thermomechanical performance, a high transparency, and high breakdown voltage as in insulators. These mechanical performances are higher than those of conventional transparent polymers, in spite of limited molecular design by bio-based molecules.

Ultrastrong, Transparent Polytruxillamides Derived from Microbial Photodimers

Co-reporter:Seiji Tateyama, Shunsuke Masuo, Phruetchika Suvannasara, Yuuki Oka, Akio Miyazato, Katsuaki Yasaki, Thapong Teerawatananond, Nongnuj Muangsin, Shengmin Zhou, Yukie Kawasaki, Longbao Zhu, Zhemin Zhou, Naoki Takaya, and Tatsuo Kaneko

Macromolecules 2016 Volume 49(Issue 9) pp:3336-3342

Publication Date(Web):April 22, 2016

DOI:10.1021/acs.macromol.6b00220

Ultrastrong and transparent bioplastics are generated from fermented microbial monomers. An exotic aromatic amino acid, 4-aminocinnamic acid, was prepared from a biomass using recombinant bacteria, and quantitatively photodimerized, and diacid and diamino monomers that were both characterized by a rigid α-truxillate structure were generated. These two monomers were polycondensed to create the polyamides with a phenylenecyclobutane repeating backbone such as poly{(4,4′-diyl-α-truxillic acid dimethyl ester) 4,4′-diacetamido-α-truxillamide} which was processed into amorphous fibers and plastic films having high transparency. In spite of noncrystalline structure, mechanical strength of the fiber is 407 MPa at maximum higher than those of other transparent plastics and borosilicate glasses, presumably due to the tentative molecular spring function of the phenylenecyclobutanyl backbone.

Milliscale Self-Integration of Megamolecule Biopolymers on a Drying Gas–Aqueous Liquid Crystalline Interface

Co-reporter:Kosuke Okeyoshi, Maiko K. Okajima, and Tatsuo Kaneko

Biomacromolecules 2016 Volume 17(Issue 6) pp:

Publication Date(Web):April 14, 2016

DOI:10.1021/acs.biomac.6b00302

A drying environment is always a proposition faced by dynamic living organisms using water, which are driven by biopolymer-based micro- and macrostructures. Here, we introduce a drying process for aqueous liquid crystalline (LC) solutions composed of biopolymer with extremely high molecular weight components such as polysaccharides, cytoskeletal proteins, and DNA. On controlling the mobility of the LC microdomain, the solutions showed milliscale self-integration starting from the unstable gas-LC interface during drying. In particular, we first identified giant rod-like microdomains (∼1 μm diameter and more than 20 μm length) of the mega-molecular polysaccharide, sacran, which is remarkably larger than other polysaccharides. These microdomains led to the formation of a single milliscale macrodomain on the interface. In addition, the dried polymer films on a solid substrate also revealed that such integration depends on the size of the microdomain. We envision that this simple drying method will be useful not only for understanding the biopolymer hierarchization at the macroscale level but also for preparation of surfaces with direction controllability, as seen in living organisms, for use in various fields such as diffusion, mechanics, and photonics.

Solution structure of cyanobacterial polysaccharide, sacran

Co-reporter:Kazuhiro Shikinaka, Kosuke Okeyoshi, Hiroyasu Masunaga, Maiko K. Okajima, Tatsuo Kaneko

Polymer 2016 Volume 99() pp:767-770

Publication Date(Web):2 September 2016

DOI:10.1016/j.polymer.2016.08.003

•The solution structure of sacran was estimated by synchrotron X-ray scattering.•The sacran in solvent has extraordinary stiffness (109 nm of persistent length).•The sacran assemblies under concentrated conditions exhibited hierarchical structure.In this study, the solution structure of sacran, cyanobacterial polysaccharide, was estimated by synchrotron X-ray scattering. The chain conformation of sacran in solvent significantly differs depending on the concentration even though it has extraordinary stiffness (109 nm of persistent length). The sacran assemblies under concentrated conditions exhibited hierarchical structure (i.e., macroscopic liquid crystalline domain consisting of helices of sacran chains). The findings enable us to design sacran-based functional materials for various applications and to understand the molecular behavior of anionic biopolymers such as glycosaminoglycan and deoxyribonucleic acid.

Anisotropic swelling in hydrogels formed by cooperatively aligned megamolecules

Co-reporter:M. K. Okajima, R. Mishima, K. Amornwachirabodee, T. Mitsumata, K. Okeyoshi and T. Kaneko

RSC Advances 2015 vol. 5(Issue 105) pp:86723-86729

Publication Date(Web):08 Oct 2015

DOI:10.1039/C5RA18585H

Sacran is a supergiant cyanobacterial polysaccharide with an extremely high absolute molecular weight that exceeds 107 g mol−1 (molecular length: over 30 μm). Sacran forms milli-scaled orientation domains in aqueous liquid crystalline (LC) state, even in trace concentrations i.e. 0.3 wt%. Aqueous sacran films that are cast from a LC state and annealed between 70–140 °C form self-standing sheets composed of oriented hydrogels. When sacran films swell, they experience changes in size that are 70 fold higher in relation to thickness than those that occur in relation to width. Either an increase in film thickness or a decrease in sacran chain length reduces swelling anisotropy, demonstrating that stress that occurs during drying can be effectively used to propagate the cooperative alignment of LC chains on a micrometer sized scale comparable with the thickness of self-standing films.

Salt-induced reinforcement of anionic bio-polyureas with high transparency

Co-reporter:Xin Jin, Seiji Tateyama and Tatsuo Kaneko

Polymer Journal 2015 47(11) pp:727-732

Publication Date(Web):August 19, 2015

DOI:10.1038/pj.2015.58

Bio-based polyureas (PUs) are prepared by the polyaddition of a multifunctional bio-photodimer 4,4'-diamino-α-truxillic acid having two amines and two carboxyls with an aromatic isocyanate comonomer. Weight average molecular weights of the PUs range from 2.4 × 105 to 2.5 × 105 g mol−1 with a narrow distribution around 1.3. The 10% weight-loss temperature of the PUs ranges from 270 to 280 °C, whereas the softening temperature ranges between 180 and 210 °C. The PUs are well dissolved in polar organic solvents such as dimethylformamide and the cast film is prepared from these solutions. The films show high transparency and swell in the alkaline solution when the PU carboxyls are anionized. If metal nitrate salts are added to the films, mechanical properties are increased by the double interaction of the metal cation with carboxylate and nitrate with urea, which causes the films to change the color.

Uniaxial Swelling in LC Hydrogels Formed by Two-Step Cross-Linking

Co-reporter:Kittima Amornwachirabodee, Maiko K. Okajima, and Tatsuo Kaneko

Macromolecules 2015 Volume 48(Issue 23) pp:8615-8621

Publication Date(Web):November 23, 2015

DOI:10.1021/acs.macromol.5b02170

Molecularly oriented hydrogels of sacran, which is a supergiant liquid crystalline polysaccharide extracted from Aphanothece sacrum biomaterials, showing ultrahigh anisotropy of swelling is successfully prepared by two-step chemical cross-linking. Divinyl sulfone (DVS) works as a chemical cross-linker of sacran chains in a dilute aqueous solution to form hydrogels, but some of the added DVS remains in the hydrogel without cross-linking. The remaining DVS cross-links further with the preformed networks of sacran chains in liquid crystalline state during slow drying to produce in-plane oriented xerogels. The xerogels show heterogeneous anisotropy in the successive swellings steps; the linear swelling ratio in the thickness direction is 10000–40000-fold higher than that in the width direction due to the molecular orientation of the sacran hydrogels. X-ray diffraction imaging of the hydrogels reveal not only the orientation of the xerogel films but also the unusual orientation of water molecules binding to sacran networks in the hydrogel state.

Syntheses of rigid-rod but degradable biopolyamides from itaconic acid with aromatic diamines

Co-reporter:Mohammad Asif Ali, Seiji Tateyama, Tatsuo Kaneko

Polymer Degradation and Stability 2014 Volume 109() pp:367-372

Publication Date(Web):November 2014

DOI:10.1016/j.polymdegradstab.2014.05.031

Highly-thermostable but degradable polyamides have been synthesized by a polycondensation of bio-derived itaconic acid salts with aromatic diamines to form heterocyclic pyrrolidone ring in the polymer backbone. The molecular weight was greater than 33,600 g/mol. Glass transition temperatures, Tg, and 10% weight loss temperatures, T10, ranged 156–242 °C and 370–400 °C, respectively, which were higher than those of conventional bio-based plastics. However their processability was too low to process the fiber as specimens of mechanical tests. We then incorporated an appropriate amount of aliphatic moiety into the aromatic backbones to prepare the high-performance and processable polyamides with Tg over 115 °C and T10 over 355 °C. The processed fibers showed tensile strength and Young's modulus ranged 20–58 MPa and 0.2–2.3 GPa, respectively. The degradation behaviors inside soil and under ultraviolet-irradiation in water were additionally found.

Polarimetry-controlled fluorescent color in oriented LC biopolyesters

Co-reporter:Kai Kan;Seiji Tateyama

Macromolecular Research 2014 Volume 22( Issue 7) pp:725-730

Publication Date(Web):2014 July

DOI:10.1007/s13233-014-2081-2

Biobased Polyimides from 4-Aminocinnamic Acid Photodimer

Co-reporter:Phruetchika Suvannasara, Seiji Tateyama, Akio Miyasato, Kazuaki Matsumura, Tatsuya Shimoda, Takashi Ito, Yukiho Yamagata, Tomoya Fujita, Naoki Takaya, and Tatsuo Kaneko

Macromolecules 2014 Volume 47(Issue 5) pp:1586-1593

Publication Date(Web):February 18, 2014

DOI:10.1021/ma402499m

The development of high-performance biobased polymers such as polyimides (PIs) is indispensable to establish a sustainable green society, but it is very difficult due to the incompatibility of their monomeric aromatic diamines with microorganisms. Here, we developed biobased PIs from bioavailable aromatic diamines, which were photodimers of 4-aminocinnamic acid (4ACA) derived from genetically manipulated Escherichia coli. These biobased PI films showed ultrahigh thermal resistance with T10 values over 425 °C and no Tg values under 350 °C, which is the highest value of all biobased plastics reported thus far. The PI films also showed high tensile strength, high Young’s moduli, good cell compatibility, excellent transparency, and high refractive indices.

Double-metal complexation of heterogels containing cyanobacterial polysaccharides

Co-reporter:Maiko K. Okajima;Quyen Thi le Nguyen;Masatoshi Nakamura;Tetsuya Ogawa;Hiroki Kurata

Journal of Applied Polymer Science 2013 Volume 128( Issue 1) pp:676-683

Publication Date(Web):

DOI:10.1002/app.38261

Abstract

Cryogenic-transmission electron microscopy of metal complexes with cyanobacterial polysaccharides, sacran, extracted from Aphanothece sacrum biomaterials reveals that Nd³⁺ complexes form networks composed of thick strings with a thickness ranging 10–20 nm while Fe²⁺ ones make dense entanglement of very thin strings. When Fe²⁺ and Nd³⁺ double complexation occurs, dense nanonetworks composed of thick strings with a thickness around 10 nm are formed. Next we prepared heterogels by crosslinking poly(vinyl alcohol) chains in the presence of sacran and investigated the effects of double complexation on metal sorption. The amount of Nd³⁺ sorbed into the heterogels in the 1 : 1 miscible solution of Fe²⁺ and Nd³⁺ is higher than that in the solution containing only Nd^3+, suggesting that Fe²⁺ assists the Nd³⁺ sorption. In addition, it is found that the amount of sorbed Nd³⁺ is much higher than that of sorbed Fe²⁺ even in the acidic condition of pH 2. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Anionic complexes of MWCNT with supergiant cyanobacterial polyanions

Co-reporter:Maiko K. Okajima;Amit Kumar;Akihiko Fujiwara;Tetsu Mitsumata;Daisaku Kaneko;Tetsuya Ogawa;Hiroki Kurata;Seiji Isoda

Biopolymers 2013 Volume 99( Issue 1) pp:1-9

Publication Date(Web):

DOI:10.1002/bip.22129

Abstract

Multi-walled carbon nanotubes (MWCNTs) were well dispersed in an aqueous solution of the cyanobacterial polysaccharide, sacran, with an ultra-high molecular weight >10 million g/mol. MWCNTs powder was put into aqueous solutions of various polysaccharides including sacran and was dispersed under sonication. As a result of the turbidity measurement of the supernatant, it was found that sacran showed the highest MWCNT-dispersion efficiency of all the polysaccharides used here. Cryogenic transmission electron microscopic (Cryo-TEM) studies directly demonstrated the existence of MWCNTs in the supernatant, and high-resolution TEM observation revealed that MWCNTs covered by sacran chains made their efficient dispersion in water. Raman spectroscopy demonstrated the existence of MWCNT in dried sample from supernatant and the interaction between MWCNT and sacran. The ζ-potential measurement of the dispersion indicated the negative surface charges of the sacran/MWCNT complexes. Then the MWCNT complexes were able to fabricate by ionic interaction; electrophoresis of the anionic complex formed the sacran/MWCNT gels on the anode while the droplet of sacran/MWCNT dispersion formed gel beads in the presence of the lanthanoid cations. © 2012 Wiley Periodicals, Inc.

Syntheses of High-Performance Biopolyamides Derived from Itaconic Acid and Their Environmental Corrosion

Co-reporter:Mohammad Asif Ali, Seiji Tateyama, Yuuki Oka, Daisaku Kaneko, Maiko K. Okajima, and Tatsuo Kaneko

Macromolecules 2013 Volume 46(Issue 10) pp:3719-3725

Publication Date(Web):May 1, 2013

DOI:10.1021/ma400395b

A new synthetic route for high-performance biopolyamides with a rigid N-substituted pyrrolidone ring was developed from the biomonomer itaconic acid (IA), which was mass-produced by the fermentation of Aspergillus terreus. We used salt-type monomers composed of diacidic IA and diamines. These salts thermally converted into polyamides in the presence of sodium dihydrogen phosphate through the aza-Michael addition, followed by intramolecular cyclization to create a pyrrolidone ring in the polymer main chain. Polyamides with molecular weights ranging over 28 000 showed Tg values over 87 °C, which were higher than conventional polyamides (around 57 °C). The Young’s modulus and mechanical strength of these polyamides also showed high values of 430–2800 MPa and 90–165 MPa, respectively. In addition, the polyamides became soluble in water by ring-opening reaction of the pyrrolidone, which led to environmental corrosion by landfill or ultraviolet irradiation.

Hyperbranched Polycoumarates with Photofunctional Multiple Shape Memory

Co-reporter:Dr. Si-Qian Wang; Daisaku Kaneko;Dr. Maiko Okajima;Dr. Katsuaki Yasaki; Seiji Tateyama; Tatsuo Kaneko

Angewandte Chemie International Edition 2013 Volume 52( Issue 42) pp:11143-11148

Publication Date(Web):

DOI:10.1002/anie.201305647

Hyperbranched Polycoumarates with Photofunctional Multiple Shape Memory

Co-reporter:Dr. Si-Qian Wang; Daisaku Kaneko;Dr. Maiko Okajima;Dr. Katsuaki Yasaki; Seiji Tateyama; Tatsuo Kaneko

Angewandte Chemie 2013 Volume 125( Issue 42) pp:11349-11354

Publication Date(Web):

DOI:10.1002/ange.201305647

Hydrotalcites Catalyze the Acidolysis Polymerization of Phenolic Acid to Create Highly Heat-Resistant Bioplastics

Co-reporter:Manu Chauzar;Seiji Tateyama;Takanori Ishikura;Keitaro Matsumoto;Daisaku Kaneko;Kohki Ebitani

Advanced Functional Materials 2012 Volume 22( Issue 16) pp:3438-3444

Publication Date(Web):

DOI:10.1002/adfm.201200427

Abstract

Acidolysis polymerization has been used to prepare phenol-derived polymers such as liquid crystalline (LC) polymers, and is catalyzed by mildly-alkaline salts. The catalytic effects of hydrotalcites (HTs), which are natural alkalescent minerals with controllable basicity, are investigated on the acidolysis copolymerization of coumarates such as p-coumaric acid and caffeic acid. As a result, the LC copolymer prepared in the presence of HT with a Mg/Al ratio of 3 shows higher molecular weight values than copolymers prepared in the presence of any other alkalescent salts. On the other hand, the copolymers prepared in the presence of HTs show a clear LC state where the polymer chains are oriented on the surface of the glass fibers. The resin, which is oriented by glass fiber fillers aligning along its longitudinal axis and is annealed at 300 °C for 20 min, shows a softening temperature of 305 °C while keeping a high mechanical strength of 85 MPa and a high mechanical modulus over 1 GPa.

Spongy Hydrogels of Cyanobacterial Polyanions Mediate Energy-Saving Electrolytic Metal-Refinement

Co-reporter:Maiko K. Okajima, Masatoshi Nakamura, Tetsuya Ogawa, Hiroki Kurata, Testu Mitsumata, and Tatsuo Kaneko

Industrial & Engineering Chemistry Research 2012 Volume 51(Issue 25) pp:8704-8707

Publication Date(Web):June 8, 2012

DOI:10.1021/ie301117p

The freeze-drying of anionic megamolecules extracted from gelatinous cyanobacteria, Aphanothece sacrum, formed spongy materials capable of metal adsorption to form hydrogels. Cryogenic-transmission electron microscopy demonstrated that thicker nanofibers were formed in sacran/In3+ complexes than in sacran/Sn4+. The preferential sorption of In3+ into the hydrogels occurred in the mixed solution of In3+ and Sn4+ with concentrations below 40 mM. Since In3+ was condensed in the sponges, electrolytic refinement of indium was made using the ion-complex hydrogels at room temperature to obtain indium metal foil at a pure grade over 99.9%. Furthermore, the sponges were recovered and used again, to successfully obtain highly pure indium metal, in even the second and third trials. Thus epochal energy-saving methods for indium refinement were established using spongy hydrogels of cyanobacterial polyanions.

Photoshrinkage in Polysaccharide Gels with Trivalent Metal Ions.

Co-reporter:Maiko K. Okajima, Quyen Thi le Nguyen, Seiji Tateyama, Hideaki Masuyama, Takumi Tanaka, Tetsu Mitsumata, and Tatsuo Kaneko

Biomacromolecules 2012 Volume 13(Issue 12) pp:

Publication Date(Web):November 2, 2012

DOI:10.1021/bm301440e

The giant anionic polysaccharide “sacran”, which is composed of 6-deoxyhexoses, pentoses, uronic acids as well as hexoses, showed hydrophobization and insolubilization phenomena in response to ultraviolet light irradiation. The sacran solution became turbid, and microparticles were formed by photoirradiation. To visualize the results of this photoreaction, anionic polysaccharide gels cross-linked by metal cations were used. As a result, we observed that sacran-gels with trivalent metal ions gradually contracted depending on the photoirradiation energy. In contrast, alginate gels used as a comparison degraded instead of contracting. This photoshrinkage of the sacran gels may be attributed to the hydrophobization of uronic acid based on photodecarboxylation. We propose that sacran-metal ion gels can function as effective, photoresponsive gels.

Synthesis of well-defined hyperbranched polymers bio-based on multifunctional phenolic acids and their structure–thermal property relationships

Co-reporter:Siqian Wang, Seiji Tateyama, Daisaku Kaneko, Shin-ya Ohki, Tatsuo Kaneko

Polymer Degradation and Stability 2011 Volume 96(Issue 12) pp:2048-2054

Publication Date(Web):December 2011

DOI:10.1016/j.polymdegradstab.2011.10.003

A number of multifunctional ABx-type monomers exist in plant metabolites, and studies on the formation of hyperbranching polymers from ABx-type monomers are very significant in the development of bio-related polymeric materials. We established a method for the preparation of well-defined structures in bio-based, hyperbranched (HB) polyarylates by the copolycondensation of caffeic acid (DHCA) as an AB2-monomer and p-coumaric acid (4HCA) as an AB-monomer, using the highly efficient catalyst Na2HPO4 to regulate the polymerization speed. 1H NMR analysis revealed the time course of the formation of the hyperbranching structures. which strongly affected the glass transition and degradation temperatures, as well as the molecular weight and composition.

Mussel-mimetic strong adhesive resin from bio-base polycoumarates

Co-reporter:Daisaku Kaneko, Siqing Wang, Keitaro Matsumoto, Shougo Kinugawa, Katsuaki Yasaki, Dam Hieu Chi and Tatsuo Kaneko

Polymer Journal 2011 43(10) pp:855-858

Publication Date(Web):August 17, 2011

DOI:10.1038/pj.2011.77

We have synthesized novel Mussel-mimetic adhesive resin from biomass monomers. Because the adhesive resin contains catechol groups at its chain ends, which is similar to the chemical structure of 3,4-dihydroxyphenyl-L-alanine, produced by Mussel, it demonstrates strong adhesive characteristics onto organic and/or inorganic surfaces beyond those of the conventional instant superglue. The origin of this strong adhesive characteristic was attributed to strong hydrogen bond interaction between our new resins and oxidized and/or OH groups on the substrates.

Effects of double photoreactions on polycoumarate photomechanics

Co-reporter:Katsuaki Yasaki;Takuya Suzuki;Koji Yazawa;Daisaku Kaneko

Journal of Polymer Science Part A: Polymer Chemistry 2011 Volume 49( Issue 5) pp:1112-1118

Publication Date(Web):

DOI:10.1002/pola.24525

Abstract

We established a polymerization condition of 3-hydroxycinnamic acid, 3HCA, having photoreactive units over all the main chains. The polymers showed two types of photoreaction, that is, intramolecular E–Z isomerization and interchain [2 + 2] cycloaddition. Spectroscopic studies showed that the rate of the isomerization was higher than that of the cycloaddition. Although the original fiber was very brittle, the short-time UV-irradiation made the fiber softer and more elastic because the chain bending by the isomerization preferentially occurred. On the other hand, the long-time irradiation made the fiber harder because of the cross-linking by the cycloaddition, and simultaneously enhanced the elasticity. Besides we found that the cast film of P3HCA showed a photo-bending behavior with the convex surface facing the UV-lamp by the initial E–Z isomerization. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

Gelation Behavior by the Lanthanoid Adsorption of the Cyanobacterial Extracellular Polysaccharide

Co-reporter:Maiko K. Okajima, Toshimitsu Higashi, Ryuya Asakawa, Tetsu Mitsumata, Daisaku Kaneko, Tatsuo Kaneko, Tetsuya Ogawa, Hiroki Kurata, and Seiji Isoda

Biomacromolecules 2010 Volume 11(Issue 11) pp:

Publication Date(Web):October 5, 2010

DOI:10.1021/bm101012u

The self-organization behavior of an extracellular polysaccharide (sacran) extracted from the cyanobacterium Aphanothece sacrum in response to lanthanoid ion adsorption was investigated. Consequently, cryogenic TEM images revealed that sacran could be cross-linked by Nd3+ trivalent ions and formed a fibrous nanostructural network containing water. Furthermore, sacran adsorbed trivalent metal ions at a 3:1 ratio, which was the theoretical ionic adsorption and showed more efficient adsorption than alginate based on electric conductivity titration. The critical gelation concentrations, Cg, where sacran formed tough gels upon metal ion binding were estimated. The Cg for trivalent metal ions was lower than that for divalent ions, and the Cg for lanthanoid ions was particularly low at 10−3 to 10−4 M, changing every four elemental numbers. The extracellular matrix of Aphanothece sacrum, sacran, may adsorb metal ions to create fibrous nanostructures that reinforce the jelly matrix.

Cyanobacterial Polysaccharide Gels with Efficient Rare-Earth-Metal Sorption

Co-reporter:Maiko K. Okajima, Masatoshi Nakamura, Tetsu Mitsumata and Tatsuo Kaneko

Biomacromolecules 2010 Volume 11(Issue 7) pp:

Publication Date(Web):June 18, 2010

DOI:10.1021/bm100231q

The cyanobacterial polysaccharide sacran, which contains carboxylate and sulfate groups, was extracted from Aphanothece sacrum, and the metal sorption behavior of sacran was investigated. Heterogels, where the sacran chains were trapped by polyvinyl alcohol networks, were prepared and immersed in NdCl3 solutions to shrink and cloud due to Nd binding. These heterogels had the ability to sorb excessive amounts of Nd ions, more than the stoichiometric ratio of 1:3 (sacran anion/Nd). Furthermore, the sacran-containing gels sorbed Nd ions under highly acidic conditions below pH 2 more efficiently than alginate-containing gels. We speculated that the strong Nd condensation effect of the sulfate groups in sacran under the acidic conditions may enhance the Nd sorption to the carboxylate groups.

Cyanobacteria That Produce Megamolecules with Efficient Self-Orientations

Co-reporter:Maiko K. Okajima, Daisaku Kaneko, Tetsu Mitsumata, Tatsuo Kaneko and Junji Watanabe

Macromolecules 2009 Volume 42(Issue 8) pp:3057-3062

Publication Date(Web):March 3, 2009

DOI:10.1021/ma802829x

Liquid crystallization of structural megamolecules in plants is very significant in understanding of biopolymer self-orientation and developing plant-derived functional materials. Cyanobacterial megamolecules, sacrans (molecular weight: 1.6 × 107 g/mol), are polysaccharides derived from the extracellular matrix of Aphanothece sacrum, and are observed as self-orienting micro rods longer than 3 μm in dilute solution at c = 0.01 wt % by optical microscopes. Sacran chains form double helixes at c > 0.09 wt % and form huge domains (centimeter scale) of liquid crystals at c > 0.5 wt % which is quite low when compared to conventional liquid crystalline polysaccharides. Mesogenic helical chains of sacrans have extremely high aspect ratios of 1600 for highly persistent lengths of 32 μm.

Cyanobacterial Megamolecule Sacran Efficiently Forms LC Gels with Very Heavy Metal Ions†

Co-reporter:Maiko K. Okajima, Shinji Miyazato and Tatsuo Kaneko

Langmuir 2009 Volume 25(Issue 15) pp:8526-8531

Publication Date(Web):March 16, 2009

DOI:10.1021/la8036956

We extracted the megamolecular polysaccharide sacran, which contains carboxylate and sulfate groups, from the jellylike extracellular matrix (ECM) of the cyanobacterium Aphanothece sacrum, which has mineral adsorption bioactivity. We investigated the gelation properties of sacran binding with various heavy metal ions. The sacran chain adsorbed heavier metal ions such as indium, rare earth metals, and lead ions more efficiently to form gel beads. In addition, trivalent metal ions adsorbed onto the sacran chains more efficiently than did divalent ions. The investigation of the metal ion binding ratio on sacran chains demonstrated that sacran adsorbed gadolinium trivalent ions more efficiently than indium trivalent ions. Gel bead formation may be closely correlated to the liquid-crystalline organization of sacran.

Supergiant Ampholytic Sugar Chains with Imbalanced Charge Ratio Form Saline Ultra-absorbent Hydrogels

Co-reporter:Maiko K. Okajima, Takeshi Bamba, Yasuhiro Kaneso, Kazumasa Hirata, Eiichiro Fukusaki, Shin’ichiro Kajiyama and Tatsuo Kaneko

Macromolecules 2008 Volume 41(Issue 12) pp:4061-4064

Publication Date(Web):May 30, 2008

DOI:10.1021/ma800307w

High-performance functional ecopolymers based on flora and fauna

Co-reporter:Tatsuo Kaneko

The Chemical Record 2007 Volume 7(Issue 4) pp:

Publication Date(Web):30 JUL 2007

DOI:10.1002/tcr.20122

Liquid crystalline (LC) polymers of rigid monomers based on flora and fauna were prepared by in-bulk polymerization. Para-coumaric (p-coumaric) acid [4-hydroxycinnamic acid (4HCA)] and its derivatives were selected as phytomonomers and bile acids were selected as biomonomers. The 4HCA homopolymer showed a thermotropic LC phase only in a state of low molecular weight. The copolymers of 4HCA with bile acids such as lithocholic acid (LCA) and cholic acid (CA) showed excellent cell compatibilities but low molecular weights. However, P(4HCA-co-CA)s allowed LC spinning to create molecularly oriented biofibers, presumably due to the chain entanglement that occurs during in-bulk chain propagation into hyperbranching architecture. P[4HCA-co-3,4-dihydroxycinnamic acid (DHCA)]s showed high molecular weight, high mechanical strength, high Young's modulus, and high softening temperature, which may be achieved through the entanglement by in-bulk formation of hyperbranching, rigid structures. P(4HCA-co-DHCA)s showed a smooth hydrolysis, in-soil degradation, and photo-tunable hydrolysis. Thus, P(4HCA-co-DHCA)s might be applied as an environmentally degradable plastic with extremely high performance. © 2007 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 7: 210–219; 2007: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20122