Articles in 2017

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.

A focused review of photoresist strategies that have been studied over the past few decades driven by the demands of Moore’s law. Selected results are discussed with emphasis on the choice of photoresist chemistry depending on the particulars of each radiation type or patterning strategy, while we present special architectures of photoresists that have attracted a great interest in the semiconductor field.

Antimicrobial cationic polymers mainly contain two functional components: the cationic groups and the hydrophobic groups. The antimicrobial activity is influenced by the type, amount, location and distribution of these two components. This review summarizes the structural designs of antimicrobial cationic polymers from primary to secondary structures, from covalent to noncovalent syntheses and from bulk to surface. It will provide some guidelines for developing molecular engineering of antimicrobial cationic polymers with tailor-made structures and functions.

In this review, we summarize the use of Diels–Alder reaction in the synthesis of arylene-based polymers, including polyphenylenes and ladder polymers, as well as graphene nanoribbons. These polymer materials are structurally related to each other, but rarely discussed all together in a same context. The importance and versatility of the Diels–Alder polymerization is highlighted for the synthesis of such polymers with various potential applications, for example, as polymer electrolyte membrane and organic semiconductors.

Organic polymers for hydrogen storage and their molecular design were reviewed. Porous organic polymers reversibly stored and released hydrogen through hydrogen physisorption on their highly porous structures. Polymers containing ketone or N-heterocycle groups fixed and stored hydrogen under atmospheric pressure through the formation of chemical bonds: the hydrogenated polymers released hydrogen in the presence of catalysts at mild conditions. The advantages of the polymers enable easy handling and provide portable hydrogen-carrying materials for use in, for example, a home/on-site or pocketable hydrogen-supply system.

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.

This review focuses on the physicochemical characterization of polyion complex (PIC) micelles, particularly addressing the critical molecular factors to determine the self-assembly scheme of double-hydrophilic block copolymers composed of charged and non-charged segments into micelle structures. The process of PIC micelle formation provides new insights on the block copolymer self-assembly in thermodynamically equilibrium condition in aqueous medium, such as chain length recognition and transition from uPIC, which is the PIC of smallest neutralizing unit, to PIC micelle structures.

Synthesis and dynamic nature of macromolecular systems having mechanically linked polymer chains, which can undertake the topology transformation, are described. The rotaxane linking of polymer chains plays a crucial role in these systems. Successful syntheses of macromolecular [2]rotaxane (M2R) possessing single polymer axle and one crown ether wheel made possible the development of topology-transformable polymers from star to linear. Furthermore, rotaxane-linked ABC triblock copolymer and 4-arm and 6-arm star polymers were also synthesized and transformed to other topological polymers along with the property change.

The development of reversible-deactivation radical polymerization (RDRP) has made a great contribution not only to control of molecular weight and terminal structures but also to precise syntheses of copolymers. In particular, introducing a new concept into RDRP allows ‘sequence control’, which might lead to construction of ‘alphabet polymer’ bearing well-defined sequence like peptides in nature. Herein, some methodologies to realize sequence control based on RDRP are reviewed.

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.

Diverse functionalized insulated conjugated polymers (ICPs) were synthesized via co-polymerization between insulated conjugated monomers and various functional units. The functional moieties strongly affected their π-conjugation, which provided sensitivity towards external stimuli. Chemical and physical inputs, such as redox, light, ions and gases, could be detected by modulating their optical and electrical properties. Moreover, the insulating structures inhibited undesired π–π interactions and prohibited thermal fluctuation in the conjugated backbones, enhancing the physical properties of the sensing materials. Accordingly, cooperative effects were observed between the insulation and functional moieties in functionalized ICPs.