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Relationship Between the Free Radical Polymerization Rates of Methacrylates and the Chemical Properties of their Monomeric Radicals
Author(s) -
Cinar Sesil Agopcan,
De Proft Frank,
Avci Duygu,
Aviyente Viktorya,
De Vleeschouwer Freija
Publication year - 2015
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.201400484
Subject(s) - radical , chemistry , monomer , photopolymer , polymerization , methacrylate , polymer chemistry , radical polymerization , nucleophile , stacking , photochemistry , bulk polymerization , polar , organic chemistry , polymer , physics , astronomy , catalysis
In this study, the rate of photopolymerization ( R p ) of 21 alkyl methacrylates is correlated with the chemical properties of their monomeric radicals by making use of the enthalpic and polar effects of these radicals. Based on these properties, a general non‐linear expression is derived by optimizing the radicals and evaluating both their stability and polar effects, via the radical electrophilicity, using density functional theory. The expression performs quite well in predicting R p for 16 of the 21 methacrylates with an R 2 value of 0.9384, but does not hold for too unstable and/or too nucleophilic radicals. Increasing the stability or decreasing the nucleophilicity of the monomeric radical results in a higher polymerization rate; in addition, the influence of the polar effects becomes larger for more stable radicals. Methacrylates containing a pendant phenyl, where π–π stacking plays an important role, are experimentally found to have a higher polymerization rate than predicted.