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Showing 1–4 of 4 results
Advanced filters: Author: Miyuki Oshimura Clear advanced filters

  • Our recent studies on the zincate complex dilithium tetra-tert-butylzincate-catalyzed transesterification and polymerization are reviewed. In the first part of this report, the ROP of ε-caprolactone catalyzed by TBZL is described. In the second part of this report, the acylation and transesterification of alcohols with vinyl acetate and carboxylic esters catalyzed by TBZL are summarized. Next, TBZL-catalyzed polycondensations of diphenyl carbonate (DPC) with diols are discussed. In the last part of this report, the transesterifications of poly(phenyl methacrylate) (PPhMA) side chains with alcohols catalyzed by TBZL are described.

    • Miyuki Oshimura
    Reviews
    Polymer Journal
    Volume: 53, P: 249-255

  • This paper reports multivariate analyses such as principal component analysis and partial least-squares regression of NMR spectra of poly(N-isopropylacrylamide)s [poly(NIPAAm)s]. Principal component analysis successfully interpreted the assignments of 1H and 13C NMR spectra of methylene protons and methine carbons, respectively, of poly(NIPAAm)s in terms of stereostructures. Furthermore, triad tacticity was successfully predicted by partial least-squares regression of 1H NMR spectra of the methine and methylene groups. Consequently, it is assumed that chemometric analysis of NMR spectra is a promising method for the characterization of synthetic polymers.

    • Tomohiro Hirano
    • Takuya Anmoto
    • Koichi Ute
    Research
    Polymer Journal
    Volume: 44, P: 815-820

  • Ring-opening polymerization (ROP) of ɛ-caprolactone with dilithium tetra-tert-butylzincate (TBZL) in toluene was performed. The initiating species for the ROP of ɛ-caprolactone is not the tert-butyl anion of TBZL but the hydroxyl anion derived from a trace amount of H2O or alcohol. Poly(ɛ-caprolactone) with a BnO group at the initiating chain-end was obtained by adding benzyl alcohol as an initiator, as expected. The molecular weight distributions were relatively narrow, except with increased temperatures and/or prolonged polymerization times. This system does not need a high polymerization temperature or long polymerization time.

    • Miyuki Oshimura
    • Ryo Okazaki
    • Koichi Ute
    Research
    Polymer Journal
    Volume: 46, P: 866-872