Synthesis of novel hyperbranched polymer through cationic ring‐opening multibranching polymerization of 2‐hydroxymethyloxetane |
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Authors: | Toshifumi Satoh Masaki Tamaki Tsukasa Taguchi Hideki Misaka Nguyen To Hoai Ryosuke Sakai Toyoji Kakuchi |
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Affiliation: | 1. Division of Biotechnology and Macromolecular Chemistry, Faculty of Engineering, Hokkaido University, Sapporo 060‐8628, Japan;2. Division of Biotechnology and Macromolecular Chemistry, Graduate School of Engineering, Hokkaido University, Sapporo 060‐8628, Japan;3. Department of Materials Chemistry, Asahikawa National College of Technology, Asahikawa 071‐8142, Japan |
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Abstract: | The cationic ring‐opening multibranching polymerization of 2‐hydroxymethyloxetane ( 1 ) as a novel latent AB2‐type monomer was carried out using trifluoromethane sulfonic acid or trifluoroboron diethyl etherate by a slow‐monomer‐addition (SMA) method. The polymer yield of poly‐1 ranged from ca. 58–88%, which increase with the increasing monomer addition time on the SMA method. The absolute molecular weights (Mw,MALLS) and the polydispersities of poly‐1 were in the range of 8,000–43,500 and 1.45–4.53, respectively, which also increased with the increasing monomer addition time. The Mark‐Houwink‐Sakurada exponents α in 0.2 M NaNO3 aq. were determined to be 0.02–0.25 for poly‐1 , indicating that poly‐1 has compact forms in the solution because of the highly branched structure. The degree of the branching value of poly‐1 , which was calculated by Frey's equation, ranged from ca. 0.50 to 0.58, which increased with the increasing monomer addition time. The steady shear flow of poly‐1 in aqueous solution exhibited a Newtonian behavior with steady shear viscosities independent of the shear rate. The results of the MALLS, NMR, and viscosity measurements indicated that poly‐1 is composed of a highly branched structure, i.e., the hyperbranched poly (2‐hydroxymethyloxetane). © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 |
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Keywords: | cationic polymerization hyperbranched ring‐opening polymerization slow‐monomer‐addition |
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