The use of spin traps for the kinetic investigation of elementary events of pseudoliving radical reversible addition-fragmentation chain-transfer polymerization

Autor: Ganna Gryn'ova, Vladimir B. Golubev, Michelle L. Coote, Ching Yeh Lin, Anatoly Filippov, Elena V. Chernikova
Rok vydání: 2011
Předmět:
Zdroj: Polymer Science Series C. 53:14-26
ISSN: 1555-614X
1811-2382
DOI: 10.1134/s1811238211040023
Popis: The spin-trapping technique is used for the first time to study the kinetics and mechanism of addition and fragmentation elementary events in reversible addition-fragmentation chain-transfer pseudoliving radical polymerization. As shown by the example of the spin-trap-reversible addition-fragmentation chaintransfer agent model system, the constants of addition (substitution) of the model tert-butyl radical to polymeric reversible addition-fragmentation chain-transfer agents (poly(styrene dithiobenzoate), poly(n-butyl acrylate) dithiobenzoate, etc.) are one to two orders of magnitude higher than the constants of addition reactions involving low-molecular-mass reversible addition-fragmentation chain-transfer agents (tert-butyl dithiobenzoate, benzyl dithiobenzoate, di-tert-butyl trithiocarbonate, and dibenzyl trithiocarbonate). This circumstance makes it possible to significantly widen the synthetic possibilities of reversible addition-fragmentation chain-transfer polymerization. Rate constants of the fragmentation reaction for a number of intermediates are estimated, and the relationship between their structure and stability is ascertained. For the model reaction of the interaction (addition and fragmentation) of the tert-butyl radical with low-molecular-mass reversible addition-fragmentation chain-transfer agents, equilibrium constants are calculated via the methods of computational chemistry.
Databáze: OpenAIRE
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