Water resources articles within Polymer Journal

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  • Note |

    The Suzuki–Miyaura coupling reaction of BrC6H4-SiRR’-C6H4Br 1 with phenylboronic acid 3 in the presence of tBu3PPd precatalyst 4 and CsF/18-crown-6 produced a phenyl-disubstituted product, indicating that the Pd catalyst underwent catalyst transfer on the silylene group. The polycondensation of 1 and phenylenediboronic acid 2 yielded cyclic polymers even when excess 1 was used. The obtained cyclic polymers containing the silylene group showed stronger fluorescence in solution than did the methylene counterpart.

    • Natsumi Harada
    • , Rina Yachida
    •  & Tsutomu Yokozawa

  • Original Article |

    Bridged polysilsesquioxanes are promising materials for reverse osmosis membranes because they exhibit robust properties. To investigate the effects of the polarity and rigidity of organic components of the polymer on the water permeability of the membrane, two alkoxysilane monomers, 2,5-bis[2-(triethoxysilyl)vinyl]pyridine (BTES-VP) and 1,4-bis[2-(triethoxysilyl)vinyl]benzene (BTES-VB), were synthesized. Both membranes prepared from BTES-VP and BTES-VB rejected 95–97% of aqueous sodium chloride and displayed water permeances of 1.1 × 10−13 and 8.5 × 10−14 m3/(m2· Pa· s), respectively.

    • Kazuki Yamamoto
    • , Ibuki Saito
    •  & Takahiro Gunji

  • Focus Review |

    A new type of asymmetric chirogenic polymerization by asymmetric allylic substitution catalyzed by planar–chiral ruthenium complexes was designed. The polymerization systems function in a highly stereoselective manner. The asymmetric carbon in the main chain is precisely controlled. Each monomer unit of the polymer has a potentially reactive terminal olefin, which can be used for further transformations, ring-closing metathesis and thiol–ene reaction. Additionally, the resulting polymer can be transformed poly “arylopeptide”, through reductive cleavage of the N–O bond in N-alkoxyamide, which adopts a one-handed stable helical conformation in solution.

    • Naoya Kanbayashi

  • Review |

    Water desalination through a reverse osmosis (RO) membrane is an important technology for producing pure water from seawater. High-performance membrane materials have been extensively developed because these materials are useful as core elements in practical water separation processes. Bridged polysilsesquioxane (PSQ)-derived membranes are promising candidates for robust RO membranes because they exhibit high thermal stability and chlorine resistance compared to conventional aromatic polyamide membranes. This review reports on our recent studies involving the development of RO membranes based on bridged PSQs.

    • Kazuki Yamamoto
    •  & Joji Ohshita

  • Original Article |

    New organically bridged trialkoxysilanes containing 1,2,3-triazole moieties were synthesized. They were polymerized by sol–gel reactions, giving bridged silica membranes. Water separation properties of the membrane were investigated using a 2000 p.p.m. NaCl aqueous solution, as being 3.7–5.4 × 10−13 m3/m2·Pa· s of water permeance and 95–96% of NaCl rejection. Separation of neutral solutes such as 2-propanol, glucose and maltose from water by the membrane was also examined. The cutoff molecular weight (solute molecular weight on 90% rejection) was estimated to be 165.

    • Kazuki Yamamoto
    • , Masakoto Kanezashi
    •  & Joji Ohshita

  • Original Article |

    Polymeric materials can be directly converted into molecular recognition materials by applying alternative molecular imprinting. This is expected to produce adsorbents that can specifically adsorb cesium ions. To this end, a polymeric adsorbent was converted from polyacrylonitrile, adopting cesium chloride as a print molecule. As a result, Cs+-recognition sites were formed in the presence of CsCl during the adsorbent preparation process. The adsorbents obtained in the present study are expected to be useful as specific adsorbents for capturing the nuclear waste, Cs+.

    • Hironao Iwasaki
    •  & Masakazu Yoshikawa

  • Invited Review |

    Susceptible situation of water molecules in the vicinity of lopsidedly charged copolymer films (upper) and a zwitterionic copolymer film. The charge-neutralized polymer surface is less perturbative to the structure of vicinal water. The image first published in Kobunshi 39, 445 (Hot Topics) (2014).

    • Hiromi Kitano

  • Note |

    We developed a facile and efficient material for mercury based on a polymer combining metal-complexation and acidic aqueous solution-soluble groups. Because the polymer is soluble in acidic aqueous solution, the metal-complexation proceeds homogeneously and efficiently. As metal complexation progresses, cross-linking takes place between the metal-complexation groups and the metal ions, precipitating the polymer complex, which can be easily separated by filtration.

    • Daisuke Nagai
    • , Akiko Nakazato
    •  & Hisatoyo Morinaga

  • Original Article |

    Single-chain crosslinked star polymers with hydrophilic and thermoresponsive poly(ethylene glycol) short arms and a hydrophobic core were created as novel microgel star polymers of single polymer chains via the intramolecular crosslinking of self-folding amphiphilic random copolymers in water. For this, well-controlled amphiphilic random copolymers bearing hydrophobic olefin pendants were synthesized as self-folding precursors by ruthenium-catalyzed living radical polymerization and the subsequent introduction of olefin units. The copolymers with 20–40 mol% hydrophobic units efficiently gave single-chain crosslinked star polymers in water.

    • Takaya Terashima
    • , Takanori Sugita
    •  & Mitsuo Sawamoto

  • Original Article |

    Applications of l-Glu molecularly imprinted cellulose membranes to chiral separation were studied. LiCl, which was adopted to dissolve cellulose into solvent, N,N-dimethylactamide (DMAc), worked well as a print molecule to construct recognition sites toward Li+ (or LiCl). The chiral separation ability was greatly dependent on LiCl. The permselectivity was increased with the LiCl concentration and asymptotically reached the maximum value at higher LiCl concentration region. The affinity constants between LiCl and LiCl recognition sites in both control and l-Glu molecularly imprinted membranes were determined to be 65 mol−1 dm3.

    • Yoshitaro Nakai
    •  & Masakazu Yoshikawa

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