Seiji Tateyama

Hyperbranched Polycoumarates with Photofunctional Multiple Shape Memory

In good shape: The films of hyperbranched polycoumarate derivatives can undergo a reversible [2+2] cycloaddition under irradiation of UV light and behave like photomechanical elastomers. From a predetermined original shape A the photonically and thermally memorized shapes B and C were obtained. The original shape was recovered by photoirradiation (see picture; Tg =glass transition temperature).

Polyhedral Oligomeric Silsesquioxanes with Controlled Structure: Formation and Application in New Si-Based Polymer Systems

Features of the formation of cage oligomeric silsesquioxanes, including several new compounds, are described and possible reaction mechanism is proposed. Synthesis of phenyl oligomeric silsesquioxanes selectively functionalized at the 4-position is reported. Formation and utilization of incompletely condensed oligomeric silsesquioxanes are also described.

Clay-bionanocomposites with sacran megamolecules for the selective uptake of neodymium

Sacran, an anionic megamolecular polysaccharide extracted from the cyanobacterium Aphanothece sacrum, is an interesting biopolymer for developing functional clay-based bionanocomposites due to its colloidal and metal complexing properties. This work introduces novel bionanocomposites based on the assembly of sacran to sepiolite, a fibrous hydrated magnesium silicate, reporting some of their special features. Sacran–sepiolite films show tensile moduli about twice that of neat sacran films, and improved resistance and integrity in aqueous solutions. These materials can act as adsorbents of lanthanide ions, profiting from the well-known adsorption properties of sepiolite and the ability of sacran to complex rare earth and heavy metal ions. Sacran–sepiolite materials show a clear preference for Nd3+ ions over Ce3+, Eu3+ and Gd3+, and the results confirm the influence of the conformation of sacran chains in crystalline domains on the adsorption properties. In fact, only those materials prepared from concentrated sacran solutions, with the polysaccharide chains arranged as liquid crystals, and involving around 27% (w/w) of sepiolite showed a remarkable synergistic effect on the retention of Nd3+ ions, being promising as biosorbents for the effective and selective recovery of neodymium from aqueous media.

1H NMR and FT-IR dataset based structural investigation of poly(amic acid)s and polyimides from 4,4′-diaminostilbene

Structural investigation of polymers by various available analytical methods is important in order to correlate the structure with polymer properties for which understanding of polymer structure is very important factor. The data presented here in this article shows the 1H NMR spectra used for the characterization of prepared poly(amic acid)s (PAAs). It is often difficult to assigns the peak in NMR of polymers due to its complexity. Data presented here helps in assigning the proton peak in complex NMR of PAAs prepared from aromatic diamines. Further functionality in polymer chains can be confirmed by FT-IR spectra. Change in functionality during some reaction or process can be monitored by disappearance or appearance of peaks in FT-IR. The complete imidization of PAAs to Polyimides (PIs) is difficult to analyze because of the chemical stability i.e. insolubility of PIs in most of the solvent therefore the completion of imidization process was confirmed using FTIR.

Novel π-conjugated bio-based polymer, poly(3-amino-4-hydroxybenzoic acid), and its solvatochromism

Abstract Soluble π-conjugated polymer derived from a renewable monomer, 3-amino-4-hydroxybenzoic acid (3,4-AHBA), was synthesized by an electropolymerization. The polymer has higher solubility in common solvents, compared to polyaniline, due to the polar side groups such as carboxyl and hydroxyl. The polymer showed various chromic behaviors based on the solvation and ionization of the side groups, and gave a flexible film with a conductivity as high as that of semiconductor.

Polarimetry-controlled fluorescent color in oriented LC biopolyesters

AbstractOriented films of the thermotropic liquid-crystalline (LC) polymer, poly{3-benzylidene amino-4-hydroxybenzoic acid (3,4-BAHBA)-co-trans-4-hydroxycinnamic acid (4HCA)} (Poly(3,4-BAHBA-co-4HCA)), were prepared by shearing the LC melt. X-Ray and polarized microscopy analyses indicated that the main chains were oriented perpendicularly to the shear direction, and the benzylidene amino side chains were parallely oriented. Furthermore, the oriented film showed polarized fluorescence in which the analyzer rotation changed the emission color when the polarizer was set perpendicular to the sheared direction.

New biopolyimdies possibly applicable to heat-resistant and transparent insulator

Bioplastics are indispensable for establishing low-carbonization society in terms of long-term carbon stock in the bio-based materials. This paper reviews the recent trends and developments of high-performance biopolyimides from 4-aminocinamic acid. They had higher thermoresistance than conventional bio-based plastics and transparent plastic films owing to rigid ring structures.

High-performance biocompatible adhesives from plant-derived materials

We have synthesized novel Mussel-mimetic glues (adhesive polymer) from plant-derived monomers. Because the adhesive polymer contains catechol group at their chain ends, which is similar chemical structure of 3,4-dihydroxyphenyl-L-alanine (dopa) produced by Mussel, it demonstrated strong adhesive characteristics onto organic and/or inorganic surfaces beyond instant super glue. The origin of this strong adhesive characteristic was discussed by strong type of hydrogen bond interaction between our new polymer and oxidized and/or OH group on the substrates. We will reports that the adhesive characteristics and its foresight for applications.