| Project/Area Number |
02453107
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
高分子合成
|
|---|
| Research Institution | Kyoto University |
|---|
Principal Investigator |
HIGASHIMURA Toshinobu Kyoto University, Faculty of Engineering Professor, 工学部, 教授 (20025860)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
SAWAMOTO Mitsuo Kyoto University, Faculty of Engineering Lecturer, 工学部, 講師 (90150325)
|
|---|
| Project Period (FY) |
1990 – 1991
|
| Project Status |
Completed (Fiscal Year 1991)
|
| Budget Amount *help |
¥4,800,000 (Direct Cost: ¥4,800,000)
Fiscal Year 1991: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1990: ¥4,000,000 (Direct Cost: ¥4,000,000)
|
|---|
| Keywords | Cationic Polymerization / Living Polymerization / Initiator / Vinyl Ether / Counterion / Growing Carbocation / Lewis Acid / Activator |
|---|
| Research Abstract |
This research project was to develop new initiating systems and counteranions for living cationic polymerization of a wide variety of vinyl monomers on the basis of a new concept, "stabilization of growing carbocations by nucleophilic counteranions". The following summarizes the achievements of the 2-year project :
1) New Initiating Systems for Living Cationic Polymerization of Vinyl Ethers
Five classes of new initiating systems for living cationic polymerization of vinyl ethers have been developed, which consist of various combinations of a protonic acids (initiator) and a weak Lewis acid (activator) : (a) acetic acid derivative/zinc chloride ; (b) ring-substituted benzoic acid/zinc chloride ; (c) hydrogen halide/zinc halide ; (d) trimethylsilyl halide/zinc halide (with a carbonyl compound) ; and (e) hydrogen iodide/metal acetylacetonate. These findings have shown the concept, "stabilization of growing carbocations by nucleophilic counteranions", to be a general principle for living cat
… More
ionic polymerization of vinyl monomers.
2) Living Cationic Polymerization of Styrene
Living cationic polymorization of styrene has been achieved with use of the methanesulfonic acid/tin tetrachloride or the styrene-hydrogen chloride/tin tetrachloride initiating system in methylene chloride solvent in the presence of a salt with the chloride anion. The development of this process is important in that this is the first example of the ideal living cationic polymerization of such poorly reactive monomers as styrene, which lacks an electron-donating (cation-stabilizing) substituent.
3) Spectroscopic Analysis of the Growing Species in Living Cationic Polymerization
Mixtures of zinc chloride and the adduct of vinyl ether with a protonic acid (as a model of the growing terminal) were directly analyzed by proton nuclear magnetic resonance spectroscopy. The analysis has revealed : (a) The growing end undergoes interaction with zinc chloride and is thereby activated to propagate ; (b) the interaction is a fast reversible process ; and (c) an ionic intermediate is involved in the propagation reaction where the activated growing end attacks a monomer. Less
|
