Effect of reaction medium on the ionizing radiation-initiated cationic copolymerization of styrene derivatives

Autor: Pierre Sigwalt, Kenneth B. Wood, V. T. Stannett
Rok vydání: 1995
Předmět:
Zdroj: Journal of Polymer Science Part A: Polymer Chemistry. 33:2909-2916
ISSN: 1099-0518
0887-624X
DOI: 10.1002/pola.1995.080331708
Popis: The influence of reaction medium polarity on the ionizing radiation-initiated copolymer-ization of styrene derivatives involving unpaired carbocations is examined. In the copo-lymerization of nonpolar monomers such as p-CH3styrene/styrene, a small effect consistent with that predicted by Laidler-Eyring theory is found. In the copolymerization of nonpolar/polar monomer pairs such as p-CH3styrene/p-Clstyrene and styrene/p-Clstyrene, any such effect is masked by specific solvation phenomena. A competition between such phenomena appears to exist, in which the different cations are dominated by different interactions. The p-Clstyryl cation appears to undergo strong intramolecular complexation with the penultimate aromatic ring in nonpolar conditions; thus, this cation displays increased se-lectivity toward monomers best able to disrupt the complex. The p-CH3styryl and styryl cations do not appear to be subject to such strong complexation; thus, in nonpolar solvent, their selectivity tends towards monomers with the highest cation-solvating ability. The differing copolymerization behavior of the p-Clstyryl cation is consistent with the findings of previous investigations of the effect of reaction medium on chain transfer with these monomers. © 1995 John Wiley & Sons, Inc.
Databáze: OpenAIRE
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