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First identification of biradicals during thermal [2π + 2π] cyclopolymerization of trifluorovinyl aromatic ethers
Author(s) -
Mifsud Nicolas,
Mellon Veronique,
Jin Jianyong,
Topping Chris M,
Echegoyen Luis,
Smith Dennis W
Publication year - 2007
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/pi.2250
Subject(s) - monomer , polymerization , chemistry , biphenyl , polymer chemistry , ether , electron paramagnetic resonance , photochemistry , polymer , fluorine , ring opening polymerization , organic chemistry , nuclear magnetic resonance , physics
The thermal cyclopolymerization of three trifluorovinyl aromatic ether monomers 1,1,1‐tris (4‐trifluorovinyloxyphenyl)ethane (1), 4,4′‐bis(4‐trifluorovinyloxy)biphenyl (2) and 2,2‐bis(4‐trifluorovinyloxy‐ phenyl)‐1,1,1,3,3,3‐hexafluoropropane (3) were monitored in situ using time‐resolved electron paramagnetic resonance spectroscopy over a temperature range of 150–210 °C. The signals observed during the early stages of perfluorocyclobutyl polymer production suggest the formation of a triplet state corresponding to the proposed biradical intermediate with a strong dipole–dipole interaction. A doublet splitting shows the presence of hyperfine coupling due to fluorine. The characterization of radical species formed during the polymerization of monomer 1 using model compounds and polymerization kinetics of monomer 2 are also presented. Copyright © 2007 Society of Chemical Industry