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  • This paper reviews the synthetic strategies for HBPs with controlled DB by specially designing monomer architectures. Several research groups including our group have been overcoming the statistical determination of DB in a random polymerization by tuning the rate constant of the first substitution reactions (k1) and that of the second reaction (k2) of an AB2 monomers. As a result, HBPs with 100% DB, linear polymers (0% DB) and HBPs with any percentage of DB have been successfully synthesized.

    • Tomoya Higashihara
    • Yukari Segawa
    • Mitsuru Ueda
    Review
  • Protein adsorption on the poly(ethylene glycol) (PEG)-tethered-chain surface was almost completely suppressed by successive treatment of longer PEG chain followed by treatment of PEG (2 kDa; mixed-PEG tethered-chain surface) because of significant increase in PEG chain density. Using pentaethylenehexamine-ended PEG, which was newly designed by ourselves, antibody/PEG and oligoDNA/PEG co-immobilizations were carried out. The PEG tethered chain was found to work not only as a non-fouling character but also as an improvement in orientation of biomolecules. Thus, it is promising as a high-performance biointerface for versatile applications.

    • Yukio Nagasaki
    Review
  • Slide-ring gel with freely movable crosslinks shows extremely small Young's modulus and recovers the deformed shape to the original one instantaneously and completely. The small modulus arises from new entropic elasticity because of the heterogenous distribution of free cyclic molecules on polyrotaxane. The sliding elasticity appears in the sliding state, where axis polymer chains and cyclic molecules are sliding actively. In addition, the slide-ring gel should show the sliding transition between the rubber and sliding states. These aspects indicate that the slide-ring gel has its unique dynamics in mechanical properties.

    • Kohzo Ito
    Review
  • Poly[2]rotaxane and graft polyrotaxane were synthesized from a mixture of poly(crown ether) as a trunk polymer, boronic-acid-terminated secondary ammonium salt as an axle component and diol as an end-capping group by pseudorotaxane formation and subsequent catalyst-free dehydrative bondage between the boronic acid and the diol moieties. It turned out that the chemical stability of these supramolecular architectures primarily depends on the bulkiness of the diol group as the end-capping moiety and the inherence originating from the dynamic covalent bond of boronate.

    • Yasuhito Koyama
    • Yudai Suzuki
    • Toshikazu Takata
    Review
  • Polyolefins (polypropylene (PP), polyethylene and so on) and polyolefin rubbers (ethylene propylene diene monomer, ethylene propylene elastomer and so on) are the most widely used polymers. Therefore, a development of a polyolefin and polyolefin rubber–clay nanocomposite has been desired for a long time. As these polyolefin polymers do not include any polar groups in its backbone, it was thought that the homogeneous dispersion of the silicate layers would not be realized. But we have successfully developed these polymer–clay nanocomposites by using various methods.

    • Makoto Kato
    • Arimitsu Usuki
    • Masaya Kawasumi
    Invited Review
  • The footprints of a macromolecular synthetic chemist were left on the sands of time. Novel anionic addition polymerization of fluorinated vinyl monomers, which generally show poor homopolymerization reactivity, has been developed. Anionic polyaddition has been achieved by the double Michael addition of bis(2-trifluoromethylacrylate)s to active methylene compounds. Radical addition of fluorinated vinyl monomers with many organic compounds possessing carbon–hydrogen bonds has been accomplished and amplified to the polyaddition reaction to incorporate fluorinated vinyl monomers into polymer main chains. The facile carbon–carbon bond formation reactions have been accomplished by the aid of fluorine substituents.

    • Tadashi Narita
    Invited Review
  • This article reviews the living homopolymerization and copolymerization of propene, 1-alkene and norbornene with ansa-dimethysilylene(fluorenyl) (amido)dimethyltitanium and its derivatives, 14, correlating with the effects of cocatalysts, solvents and the substituent of the fluorenyl ligand on the catalytic features, such as livingness, propagation rate, syndiospecificity and copolymerization ability. The synthesis of novel olefin block copolymers and their catalytic synthesis are also introduced by the use of the living system.

    • Takeshi Shiono
    Invited Review
  • The movement toward a recycling-based society through the essential development of recyclable materials alongside technologies for controlling recycling, for example, upgrade recycling of commodity plastics, selective transformation of engineering plastics, selective depolymerization of various polymers in supercritical fluids, crosslinking-decrosslinking control using reversible reactions and developments in biomass-based recyclable polymers is reviewed.

    • Haruo Nishida
    Invited Review
  • New types of polymer hydrogels (nanocomposite gels, NC gels) and soft polymer nanocomposites (M-NCs) with novel organic/inorganic network structures were synthesized using disk-like inorganic clay nanoparticles as multifunctional crosslinkers to form new network systems. Both NC gels and M-NCs have extraordinary optical and mechanical properties, such as ultrahigh reversible extensibility, as well as a number of new characteristics relating to polymer/clay morphology, stimulus-sensitivity, biocompatibility, surface properties, micropatterning and so on. The serious disadvantages (intractability, mechanical fragility, optical turbidity, poor processing ability, low stimulus sensitivity) associated with the conventional, chemically crosslinked polymeric materials were overcome in NC gels and M-NCs.

    • Kazutoshi Haraguchi
    Invited Review