1997 Fiscal Year Final Research Report Summary
Preparation Dendrimer Like Polymer by Radical Polymerization
| Project/Area Number |
08651057
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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 |
高分子合成
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| Research Institution | Osaka city University |
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Principal Investigator |
YAMADA Bunichiro Osaka City Univ., Faculty of Engineering, Professor, 工学部, 教授 (50047198)
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| Project Period (FY) |
1996 – 1997
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| Keywords | Radical polymerization / Star Polymer / Block Copolymer / Addition-fragementation Chain Transfer / End Group / Branched Structure / Moleculer Weight / Gelation |
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| Research Abstract |
Some of alpha-(substituted methyl) acrylates function as effective addition-fragmentation chain transfer agent depending on the substituent, and this type of chain transfer could form C-C bond between the polymer chain end and the moiety form the transfer agent leading to a minimum contribution of conventional bimolecular termination. As a result, vinyl polymerization in the presence of a small amount of multifunctional addition-fragmentation chain transfer agent could link polymer chains. Methylalpha- (benzylthiomethyl) acrylate (1) functions as effective transfer agent in polymerization of methyl methacrylate (MMA) to decrease M_n of the resultant polymer, and the fragment from 1 was quantitatively bound to the polymer end. Although the unsaturated end group remained at the polymer end during the MMA polymerization, the stirene (St) polymerization in the presence of the poly-(MMA) with the unsaturated end group yielded branched or star block copolymer through addition of poly (St) radical to the end group. When ethylene bis [alpha-(benzylthiomethyl)-acrylate] (2) was employed as a bifunctional addition-fragmentation chain transfer agent for MMA polymerization, two poly (MMA) chains were connected through the moiety from 2. Noteworthy is that no gelation is induced. The addition of poly (St) radical lead to branched or star blook copolymer bearing more arms, and no gelation by crosslinking was observed. Furthermore, a polymerizable addition-fragmentation chain transfer agent (3) consisting of alpha-(acyloxymethyl) acryloyl and alpha-(benzylthiomethyl) acryloyl groups was synthesized and added to the polymerization of MMA.The resulting poly (MMA) contains the branches to which the branching points from 3 were introduced. Further addition of poly (St) radical proceeded to give hyperbranched block copolymer without gel formation. However, premature homopolymerization of St could not be suppressed.
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