1991 Fiscal Year Final Research Report Summary
Studies of Radical Polymerization by Using Long-lived Propagating Polymer Radicals
| Project/Area Number |
02453108
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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 | The University of Tokushima |
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Principal Investigator |
SATO Tsuneyuki The University of Tokushima, Faculty of Engineering, Professor, 工学部, 教授 (20047187)
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| Co-Investigator(Kenkyū-buntansha) |
TANAKA Hitoshi The University of Tokushima, Faculty of Engineerig, Associate Professor, 工学部, 助教授 (40127840)
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| Project Period (FY) |
1990 – 1991
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| Keywords | Radical Polymerization / Propagating Polymer Radical / ESR Spectrum / Rate Constant of Propagation / Rate Constant of Termination / Lewis Acid Effect / Solvent Effect |
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| Research Abstract |
Itaconic acid derivatives and some related monomers were found to be easily polymerized by radical initiators in spite of their two bulky alpha -substituents. The polymerization systems were observed to involve ESR-detectable propagating polymer radicals under the actual polymerization conditions. Using the polymer radical concentration determined by ESR, we succeeded in estimating the rate constants of propagation (k_p) and termination (k_t) of these monomers. The k_p and k_t values of dialkyl itaconates decrease as the alkyl chain becomes longer. The steric effect due to the alkyl group suppresses much more termination than propagation, leading to the fact that the monomer with longer alkyl group shows a higher polymerization rate. The k_p value of dioctyl itaconate is smaller in a more polar solvent. The considerable solvent effect is explicable in terms of affinity of the propagating polymer radical for the solvent used. The presence of SnCl_4 reduces both the k_p and k_t values of diethyl itaconate, which seems to be due to an entropy factor. k_p (990 l/mols, 60ﾟC) of ethyl alpha -benzoyloxymethylacrylate (EBMA) is much larger (about two factors) than those of itaconates, and k_t (2.9x10^6 l/mol s) of EBMA is ten times those of itaconates. Methyl N-phenylitaconamate shows the k_p (8.2 l/mol s) and k_t (1.9-4.2 l/mol s) values 55ﾟC similar to those of itaconates. k_p (24-27 l/mol s) of N- (2.6-dimethylphenyl) itaconimide at 50ﾟC is almost independent of the monomer concentration, while kt (3.8x10^4-2.0x10^5l/mols) decreases with the monomer concentration which is ascribable to dependence of k_t on the polymer chai n length. ESR spectroscopic and kinetic evidences for penultimate effect were obtained in the radical copolymerization of dibutyl itaconate with N-cyclohexylmaleimide.
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