| Project/Area Number |
15550107
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Polymer chemistry
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| Research Institution | Nara University of Education |
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Principal Investigator |
KAJIWARA Atsushi Nara University of Education, Associate Professor, 教育学部, 助教授 (50224415)
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| Project Period (FY) |
2003 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥3,800,000 (Direct Cost: ¥3,800,000)
Fiscal Year 2004: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2003: ¥2,500,000 (Direct Cost: ¥2,500,000)
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| Keywords | Radical Polymerization / Electron Spin Resonance / ESR / Radical Reaction / Copolymerization / Chain Length Dependence / Penultimate Unit Effect / Magnetic Resonance / 電子スピン共鳴 / 成長ラジカル / 原子移動ラジカル重合 / ATRP / 制御ラジカル重合 |
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| Research Abstract |
Electron Spin Resonance(ESR) study of radicals in conventional radical polymerizations using model radicals generated from polymers prepared by atom transfer radical polymerization was done. I have carried out ESR study of propagating radicals in radical polymerizations by direct detection of the radicals. In the research works, clear and well-resolved spectra have been observed. However, no information on chain length of the observed radicals had been obtained in the experiments. Since the ESR spectra have been used for estimation of propagation rate constant (kp) of the radical polymerizations, information of chain length is extremely important. Combination of controlled radical polymerization technique and ESR spectroscopy provided information of chain lengths of propagating radicals of methacrylates. Atom transfer radical polymerization(ATRP) can produce polymers with given chain lengths and narrow polydispersity. Moreover, the resulting polymers prepared by ATRP have terminal carbon-halogen bonds. The carbon-halogen bonds can be cleaved by reaction with organotin compounds to form corresponding radicals. We can observe the radicals with well-known chain lengths as model of propagating radicals. In the experiments, shorter (mixture of oligomers with 2-7 monomer units) and longer (30 50,100-mers) model radicals showed different ESR spectra. From these results, we can distinguish the chain lengths of observed radicals by ESR spectroscopy. Model dimeric radical precursors with different methacrylate/acrylate monomer units can be prepared by ATRP for investigation of penultimate unit effects. Steric and electronic effect from the penultimate units were also observed by ESR.
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