Research articles

Lignin-derived compatibilizing agents were developed for polypropylene-based carbon fiber-reinforced prastics. Introduction of acyl groups to alkali lignin improved compatibility of the lignin to both carbon fiber and polypropylene while underivatized alkali lignin did not show compatibility. The interfacial shear strength between carbon fiber and polypropylene was significantly improved by addition of the lignin derivatives as compatibilizing agents.

We prepared magnetically anisotropic soft materials by in situ synthesis of iron oxide nanoparticles in a matrix composed of κ-carrageenan and PVA followed by mechanical stretching of the hybrid in a wet process. With the orientation of the composite matrix, the incorporated iron oxide nanoparticles gathered to form elliptical clusters. The drawn samples showed different magnetizations depending on the direction of magnetic field application. The specific responses were macroscopically visualized and were attributed to the magnetic anisotropy created by the preferred orientation of the nanoparticle aggregates.

A facile and practical surface-engineering methodology to enhance the self-assembly of PS-b-PDMS BCPs with high χ by precisely controlling the molecular weight and weight percent of PS brushes. Highly ordered sub-20-nm BCP patterns were successfully obtained in a few minutes under the optimum PS brush condition.

Static light scattering measurements are carried out for poly(ethylene glycol) and poly(ethylene oxide) (PEO) of the weight-average molecular weight M _w ranging from 3×10³ to 2×10⁴ in methanol and water at 25.0 °C. Some aggregates of large size are found to be formed only in the cases of PEO of M _w∼O(10³) in aqueous solutions, although for other cases polymer chains are isolated in solutions.

The present study details the preparation of a macroporous hybrid material containing polythiophene electropolymerized onto TiO₂ nanotubes (TNT). The prepared foam-like hybrid material showed a very low charge transfer resistance. Upon decoration with Pt using our novel and green photogeneration method, the material exhibited very strong metal substrate interactions, resulting in high durability during the oxygen reduction reaction (ORR). This study proposes a novel macroporous organic/inorganic hybrid material for use as an alternative material to replace conventional carbon substrates in ORR catalysts.

We studied the elongational crystallization of poly(ethylene terephthalate) (PET) from the supercooled melt. We found that the novel three-dimensional (3D) structure of “nano-oriented crystals (NOCs)” was formed, where nanocrystals (NCs) were arranged on monoclinic lattice. We observed the structure and morphology of NOCs by means of polarizing optical microscope and small/wide angle X-ray scatterings. We clarified the important role of a primary structure of the plate-like benzene ring in the formation of the NOCs of PET. We also showed high performance of NOCs of PET, such as high heat resistance temperature and high maximum tensile stress.

The gas transport properties of polybenzoxazole (PBO)–silica hybrid membranes were investigated. The gas permeability of the PBO–silica hybrid membranes increased withincreasing silica content and thermal treatment temperature. The hybrid membranes prepared with tetraethoxysilane (TEOS) showed simultaneous enhancements in CO₂ permeability and CO₂/CH₄ selectivity with increasing silica content and thermal treatment temperature. The prominent CO₂/CH₄ separation ability might be attributable to free volume holes created around the polymer/silica interfacial area and increased intermolecular chain distance.

Recyclable carbon fiber-reinforced plastics (CFRPs) with controlled degradability and stability were developed by using acid-degradable acetal linkage-containing epoxy resin (BA-CHDMVG). The obtained BA-CHDMVG-based CFRPs exhibited almost the same tensile and thermal properties as those of the conventional BA-based CFRPs and underwent smooth degradation through hydrolysis with the treatment of hydrochloric acid in a tetrahydrofuran (THF)/water (9/1) mixed solvent. On the other hand, in the absence of organic solvents, the BA-CHDMVG-based CFRPs have sufficient stability toward acid in the normal living environment.

Equivalent circuit with two units for the 3.11 vol% PI/VGCF composite and three units for the 6.28 vol% PI/VGCF composite was proposed to study the complicated relaxation behavior. The first unit was: interface between bulk and electrode; the second unit was: interface between adjacent VGCFs inserting PI; the third unit was: carrier movement within VGCFs.

Shapeable synthesis of porous silica frameworks was achieved in an aqueous system using polyacrylamide (PAAm) gel as an organic template and hydrolyzed silicon alkoxide as a silica source. Macroscopically shaped frameworks comprised of 10- to 50-nm diameter silica particles are obtained via PAAm–silica precursor gels. The mechanical properties of the silica frameworks depending on the packing density are controlled by changing the silica content in PAAm gels.

Small-angle neutron and X-ray scattering measurements were conducted on blends of deuterated polyethylene and hydrogenateted polyethylene with various molecular weights drawn just below the melting temperature at three drawing rates to study role of molecular weigh in shish-kebab formation. It was found that low molecular weight component was mainly included in shish for the present experimental condition. The result contradicts our previous result, showing that there are various shish-kebab formation mechanisms that are not known so far.

Functional oligochitosan-nanosilica (OCS/nSiO₂) hybrid material is likely to be considered as natural vaccine for the growth and disease resistance of the plants. Study on hybrid material from low-cost and waste products such as OCS from chitosan and chitin, and nSiO₂ from rice husk is likely to create a novel material with special synergistic effect. The plants treated with OCS/nSiO₂ were not completely diseased by Colletotrichum sp. The biomass, the length, the chlorophyll content of the plants treated with OCS, nSiO₂ or OCS/nSiO₂ were higher than those of the control plants.

Using the over-1000 nm near-infrared (OTN-NIR) dye IR-1061-loaded polymer micelles, IR-1061-loaded PEG-b-PCL micelles (OTN-PNPs) were successfully obtained using a simple one-pot preparation method. The OTN-PNPs showed strong OTN-NIR emission under physiological conditions. Furthermore, the OTN-PNPs were readily biodegradable; thus, it is anticipated that the renal clearance of the degraded material will occur after imaging experiments. Moreover, in vivo imaging of a live mouse was successfully performed. The blood vessels of a live mouse could be clearly illuminated using the OTN-NIR emission of OTN-PNPs. Therefore, the OTN-PNPs are promising candidates for NIR imaging probes.

The scalability and recyclability in transesterifications of polysaccharides with 1-ethyl-3-methylimidazolium acetate (EmimOAc) as both the solvent and organocatalyst was confirmed. In addition, the EmimOAc-catalyzed transesterification protocol was expanded to a gram-scale reaction with various polysaccharide sources, such as pulps, rayon, xylan, pululan, and dextrin.

The phase behaviors of the as-prepared poly(3-dimethyl(methacryloyloxy-ethyl)ammonium propane sulfonate betaine (polySBMA) solutions at high concentrations were investigated. The solution exhibited stably reversible phase transition between transparency and opacity. The transition temperature decreased with the increase of the polymer concentrations. The polySBMA had a high equilibrium concentration, which results in the as-prepared polySBMA solution with a high concentration presented an over-swelling behavior that played an important role in the transition temperature of the solution.

The corneal endothelial scaffolds were prepared using carboxymethyl chitin (CMCT) or carboxymethyl chitosan (CMCTS) as the main ingredient. The transmittances of the membranes were examined at different wavelengths. The properties of both membranes, including cytotoxicity, histocompatibility, degradability and cytocompatibility, were determined by experiments on cultured cells or rats. By contrast, the CMCT membrane proved to be a more promising candidate for constructing CEC endothelial scaffold.

We designed a thermosetting polyurethane based on the reversible reaction between isocyanates and phenolic hydroxyls instead of alcoholic hydroxyls. The phenolic urethane partially decomposed at above 120 °C, but the phenolic hydroxyl and isocyanate reconnected upon cooling. This reversible urethane bond contributed to the thermal self-repair of the thermosetting polyurethane network and can be applied into self-healing coatings or adhesives.

Composites of poly(methyl methacrylate) synthesized by the free-radical polymerization of methyl methacrylate with Aerosol OT (AOT) surfactant added show enhanced resistance to thermal degradation and combustion. Structural analyses over the nm and μm lengthscale show that there are nanoscale domains of hexagonally packed rods and microscale domains of phase-separated surfactant. The self-assembly of AOT occurs concurrently with the combustion resistance. These results show a promising method of introducing structures that result in the desirable properties of thermal stability and combustion resistance into polymer composites.

Novel aromatic copolymers based on a thiazolothiazole (TT) unit were designed and synthesized as proton exchange membranes for polymer electrolyte fuel cells. Even a small amount of the TT unit (0.1–1 mol%) considerably affected the sizes of the hydrophilic and hydrophobic domains of the membrane surface. Furthermore, the TT-based membranes exhibited higher proton conductivities and lower activation energies than those of the parent membrane under various relative humidity conditions.