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Theoretical and Experimental Studies on Elementary Reactions in Living Radical Polymerization via Organic Amine Catalysis.
- Source :
-
Macromolecules . Apr2016, Vol. 49 Issue 7, p2511-2517. 7p. - Publication Year :
- 2016
-
Abstract
- The reaction mechanism of living radical polymerization using organic catalysts, a reversible complexation mediated polymerization (RCMP), was studied using both theoretical calculations and experiments. The studied catalysts are tetramethylguanidine (TMG), triethylamine (TEA), and thiophene. Methyl 2-iodoisobutyrate (MMA-I) was used as the low-molar-mass model of the dormant species (alkyl iodide) of poly(methyl methacrylate) iodide (PMMA-I). For the reaction of MMA-I with TEA to generate MMA• and •I-TEA radicals (activation process), the Gibbs activation free energy for the inner-sphere electron transfer mechanism was calculated to be 39.7 kcal mol-1, while the observed one was 25.1 kcal mol-1. This difference of the energies suggests that the present RCMP proceeds via the outer-sphere electron transfer mechanism, i.e., single-electron transfer (SET) reaction from TEA to MMA-I to generate MMA• and •I-TEA radicals. The mechanism of the deactivation process of MMA• to generate MMA-I was also theoretically studied. For the studied three catalysts, the theoretical results reasonably elucidated the experimentally observed polymerization behaviors. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00249297
- Volume :
- 49
- Issue :
- 7
- Database :
- Academic Search Index
- Journal :
- Macromolecules
- Publication Type :
- Academic Journal
- Accession number :
- 115158283
- Full Text :
- https://doi.org/10.1021/acs.macromol.6b00230