Abstract:
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-trifluorovinyloxyphenyl)-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 degrees 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. (c) 2007 Society of Chemical Industry.
