1988 Fiscal Year Final Research Report Summary
Copolymerization mechanism producing poly(methyl methacrylate-alt-styrene)with high coheterotacticity
| Project/Area Number |
62550662
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
高分子合成
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| Research Institution | The University of Tokyo |
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Principal Investigator |
GOTOH Yaeko Faculty of Engineering, The University of Tokyo, research associate, 工学部, 助手 (00092388)
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| Co-Investigator(Kenkyū-buntansha) |
KAWAMURA Tokiji Faculty of Engineering, The University of Tokyo, technical official, 工学部, 教務職員 (30107586)
HIRAI Hidefumi Faculty of Engineering, Science University of Tokyo, Professor, 工学部, 教授 (90010751)
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| Project Period (FY) |
1987 – 1988
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| Keywords | Heterotacticity / Alternating copolymerization / Radical copolymerization / Boron trichloride / Styrene-d_2 / Two dimensional NMR / Parameter / 一次マルコフ規制 |
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| Research Abstract |
1. Cotacticities of the poly(methyl methacrylate-a t-styrene) prepared by using BCl_3 depend on the concentration of BCl_3 and the copolymerization temperature. Highly coheterotactic alternating copolymer of MMA and styrene was synthesized at -60 and -76゜C using BCl_3 in excess to MMA. Neverthless, the presence of more than 2 moles of BCl_3 to MMA has no effect on the cotaticity. The lowering the temperature from -60 and -76゜C increased the coheterotacticity from 70 to 75 mole %. These results suggest the monomer complex composed of one MMA, one styrene and two BCl_3 as the active species for the regulation.
2. The two dimensional NMR spectrum of the copolymer reveals the further splittings due to the longer configulational sequences which did not appear in the one dimensional NMR spectrum. The sixteen peaks which are expected for tetrad sequences can be observed in the methylene proton region of the spectrum taken by a ^1H J-resolved 2D NMR method by using two samples with the differen
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t triad cotacticities. Four peaks due to mrm and rmr sequences are clearly identified using the highly coheterotactic samples. The other peaks are presumably assigned by the ^1H-^1H correlation 2D NMR (COSY) measurement.
3. The copolymerization of MMA with CD_2=CH(C_6H_5) was examined to determine the probability of isotactic addition of propagating styrene terminal to MMA monomer ( ^*_). The meso dyad cotacticities (P_m) of the obtained poly(MMA-a t-St-d_2) were determined by the 400 MHz NMR peak measurement of the methylene protons derived from MMA. Therefore, this P_m value equals to ^*_ value. Using ^*_ and P_m of poly(MMA-a t-St), ^*_, the probability of isotactic addition of MMA St, cna be calculated by the equation: P_m(MMA-St)=( <*N/)1>+ ^*_)/2. The probabilities for the highly coheterotactic copolymerization, ^*_ and ^*_, were determined to be 0.24 and 0.65, respectively. Furthermore, four parameter mechanism is adopted to this copolymerization. It means that the stereoregulation obeys the ist order Markovian statistics at the both propagating ends. Less
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Research Products
(13 results)
