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EPR Study of Backbiting in the Aqueous‐Solution Polymerization of Acrylamide
Author(s) -
Kattner Hendrik,
Buback Michael
Publication year - 2015
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.201500479
Subject(s) - acrylamide , polymer chemistry , aqueous solution , polymerization , electron paramagnetic resonance , materials science , polymer science , polymer , chemical engineering , chemistry , composite material , monomer , organic chemistry , nuclear magnetic resonance , physics , engineering
Via electron paramagnetic resonance (EPR) spectroscopy, the type of radicals occurring during acrylamide (AAm) homopolymerization in aqueous solution is investigated between −5 and +100 °C. The radicals are produced photochemically under stationary conditions. Midchain AAm radicals (MCRs) are clearly identified by EPR which demonstrates that secondary propagating AAm radicals (SPRs) undergo backbiting reactions. Above 50 °C, the fraction of MCRs even exceeds the one of SPRs. The extent of backbiting is however well below the one in butyl acrylate polymerization at identical temperature.