1995 Fiscal Year Final Research Report Summary
Syntheses and Characterizations of Multi-block Copolymers
| Project/Area Number |
06453147
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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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 | TOKYO INSTITUTE OF TECHNOLOGY |
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Principal Investigator |
NAKAHAMA Seiichi Tokyo Institute of Technology, Faculty of Engineering Professor, 工学部, 教授 (90016410)
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| Project Period (FY) |
1994 – 1995
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| Keywords | hydrophilic-hydrophobic multi-block copolymer / anionic living polymerization / stabilization of enolate anion / precise synthesis of block copolymer / sequential polymer / aggregate / protective group / microphase separation |
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| Research Abstract |
Addition of diethylzinc to the anionic polymerization system of methacrylates in THF caused stabilization of the propagating enolate anion to lower the polymerization rate and to enhance the ability of survival of the living end. Using living anionic polymerization method with diethylzinc and the protection technique, hydrophobic-hydrophilic block copolymers of poly (cesium methacrylate) and poly (isopropyl methacrylate) having 3-5 segments were synthesized. The primary structure and aggregate structure of the block copolymers were characterized by NMR and light scattering measurements. Although the block copolymer having 5 segments was insoluble in benzene, it was once dissolved in methanol and the solvent was gradually exchanged with benzene and then freeze dried. The solid polymer obtained was completely soluble in THF as a micelle having 106 g/mol. The cylindrical shape of the micelle was suggested from the TEM observation. When the polymer in THF was passed through the polystirene-gel column, the aggregate was broken down to a small size micelle of 5-10 association number. This suggests that the multi-block copolymer having ca.20 segments forms a unimer micelle.
The ABC type block copolymers having poly (HEMA), poly (tert-butyl methacrylate), and poly [(2-perfluorobutyl) ethyl methacry late] were synthesized using a similar method. The NMR data suggested that the block copolymers generated the different types of aggregates in the selective solvents, such as chloroform and methanol, depending upon the sequence of the segments.
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