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Volume 51 Issue 5, May 2019

Original Article

  • Copolymerization kinetics of methyl methacrylate and ethyl methacrylate by Cu(0)-mediated reversible deactivation radical polymerization was thoroughly explored. The copolymerization follows pseudo-first order kinetics in a highly controlled manner. Detailed kinetic studies revealed that two different monomers experience different enthalpic barriers in propagation, which strongly suggest that the copolymerization exhibits not perfectly, but nearly random composition. Further studies on glass transition and chain extension highlight the significance of these fundamental studies to predict thermal properties and to realize complex polymer architecture.

    • Jongwon Choe
    • Woo Jung Lee
    • Myungwoong Kim
    Original Article

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  • Diallylated p-coumaric acid (A2CM) and triallylated caffeic acid (A3CF) were thiol-ene photo-polymerized with a pentaerythritol-based tetrathiol (S4P) at allyl/thiol and (allyl+enone)/thiol ratios of 1/1. The FT-IR spectral analysis revealed that the reaction of allyl and thiol groups mainly progressed for the products cured at the allyl/thiol ratio of 1/1, while both allyl and enone groups reacted with thiol groups for the products cured at an (allyl+enone)/thiol ratio of 1/1. The A3CF/S4P cured at an allyl/thiol ratio of 1/1 exhibited the highest glass transition temperature, 5% weight loss temperature, tensile strength and modulus among all the cured products.

    • Mitsuhiro Shibata
    • Kaito Sugane
    • Yuto Yanagisawa
    Original Article
  • Viscoelasticity of PEG in aqueous solutions containing different concentrations of K2SO4 was studied by QCM-D, after coating a rigid supported lipid bilayer on the silicon oxide substrate. The obtained viscoelastic properties of PEG in K2SO4 solutions agree well with the Zimm model predictions for linear polymer chains. The gradual worsening of solvent quality by adding K2SO4 to aqueous PEG solutions is demonstrated by the obtained excluded volume exponents via QCM-D and the conventional intrinsic viscosity measurements.

    • Xiaoxue Wu
    • Ziliang Zhao
    • Yonggang Liu
    Original Article
  • The possibility of detecting the interfacial glass transition of polystyrene with contact angle measurements of a liquid polyethylene glycol on the polymer surface was investigated. The observed contact angle reflects the deviation from an equilibrium state at low temperatures, exhibiting a discontinuous change in the temperature dependence of the interfacial tension. The evaluated Tg was ca. 362 K, which is lower than a calorimetric Tg for a bulk polystyrene. The interfacial glass transition appears to be detected when the polymer/liquid interactions affect the wetting process.

    • Takashi Sasaki
    • Kazuaki Hiraki
    • Natsuki Takeuchi
    Original Article
  • We studied the surface functionalization of PP by dip-coating with a maleic anhydride-grafted chlorinated polypropylene (MPO) /methacrylate-based terpolymer mixture. A methacrylate-based terpolymer (PMFP) was synthesized, which contained perfluoroalkyl (Rf)-conjugated monomers and poly(ethylene glycol)-conjugated monomers. We found that the presence of MPO aided the adhesion of the terpolymer to the PP surface and that the coated PP surface exhibited low protein-fouling properties. In addition, the dip-coating of a terpolymer containing reactive groups (–COOH) with MPO caused the reactive groups to be presented at an outermost surface.

    • Manami Hara
    • Shigeru Kitahata
    • Tatsuo Maruyama
    Original Article
  • Porous hydrogels (CNF-PEG hydrogels) for the adsorption of metals from aqueous solutions were prepared from chitosan nanofibers (CNFs) and poly(ethylene glycol) diacrylate (PEGDA). CNF-PEG hydrogels adsorbed both transition metals (e.g., copper) and post-transition metals (e.g., tin). The adsorption capacity was observed to increase with increasing CNF/PEGDA ratio, indicating that the CNFs exhibit synergism between chelation between metals and chitosan, and the enlarged surface area of the porous structure.

    • Sachiko Nitta
    • Miki Akagi
    • Hiroyuki Iwamoto
    Original Article
  • Highly conductive, soft, and 3D-printable nanocomposite polymers have been developed that consists of poly (ionic liquid) (PIL), polymethylmethacrylate (PMMA) as polymeric system, multiwalled carbon nanotubes (MWCNTs) as fillers and an ionic liquid (IL) that acts as a plasticizer and dopant for the MWCNTs. The nanocomposites exhibited variable mechanical, conductive, and thermal properties depending on the composition of polymer, IL, and MWCNTs. Finally, we optimized the conditions for 3D printing and demonstrated the fabrication of a flexible, 3D-printed circuit, which can be bent and twisted without damaging the circuit.

    • Kumkum Ahmed
    • Masaru Kawakami
    • Hidemitsu Furukawa
    Original Article
  • We fabricated actuators consisting of an ionic liquid gel electrolyte layer sandwiched between two nanofiber mat electrodes and studied the relationship between the polymer type of the nanofiber mat and the performance of the actuator. We selected poly(urethane) (PU), poly(methyl methacrylate) (PMMA), and poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) as the materials for the nanofiber mat electrodes. The performance of the actuator was determined on the basis of cyclic voltammetry and AC impedance measurements.

    • Hanako Asai
    • Tomotaka Okumura
    • Koji Nakane
    Original Article
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