| Project/Area Number |
61430022
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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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 | Osaka University |
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Principal Investigator |
HATADA Koichi Osaka University, Faculty of Engineering Science, Professor, 基礎工学部, 教授 (60029402)
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| Co-Investigator(Kenkyū-buntansha) |
UTE Koichi Osaka University, Faculty of Engineering Science, Assistant Professor, 基礎工学部, 助手 (30176713)
KITAYAMA Tatsuki Osaka University, Faculty of Engineering Science, Assistant Professor, 基礎工学部, 助手 (60135671)
OKAMOTO Yoshio Osaka University, Faculty of Engineering Science, Associate Professor, 基礎工学部, 助教授 (60029501)
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| Project Period (FY) |
1986 – 1989
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| Keywords | Stereoregularity / Living Polymerization / Oligomer / Anionic Polymerization / NMR / End Group / Polymerization Mechanism / Deuterated Monomer |
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| Research Abstract |
1. The polymerization of deuterated monomer and the ^1H NMR analysis of the resultant polymer and oligomer revealed that in the polymerization of methyl methacrylate (MMA) with anionic initiators such as n-C_4H_9Li and n-C_4H_9MgCl, the initiator reacts with both the C=C and C=O double bonds of MMA at the initial stage of polymerization. The carbonyl addition forms alkyl isopropenyl ketone and the alkoxide, both of which are involved in the polymerization reaction to make it uncontrollable.
2. The polymerization of MMA in toluene with t-C_4H_9MgBr was found to proceed in a living manner without side reactions to give a highly isotactic PMMA with narrow molecular weight distribution (MWD). The polymerization with t-C_4H_9Li/R_3Al gave a highly syndiotactic PMMA with narrow MWD. Both the living polymerization systems could be utilized for the preparation of stereoregular block and random copolymers as well as macromonomer.
3. The oligomers of MMA formed at the early stage of polymerization
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with t-C_4H_9MgBr were separated and analyzed in regard of tacticity. The stereoisomer distribution showed that even the trimer anion can propagate in a highly isotactic way. Pure-isotactic and puresyndiotactic MMA oligomers up to octamers were isolated. NMR studies of these oligomers confirmed the extended chain conformation with the ... tg^+ form at the right end. Structural analysis of oligomers also provided useful information on the mechanisms of initiation reaction in the polymerzation of MMA with R_3P-R'_3Al and of asymmetric polymerization of triphenylmethyl methacrylate.
4. Isotactic and syndiotactic PMMAs prepared by the living systems mentioned above have the same chemical structure from left-end to right-end. By using these PHMA samples, thermal degradation temperature of the syndiotactic PMMA was found to be higher than that of the isotactic PMMA. Effects of stereoregularity on the properties of polymers such as NMR relaxation times and adsorption ability in liquid chromatography were also studied. The glass transition temperature of copolymers of methacrylates were found to be controlled by changing the stereoregularity as well as their compositions. Less
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