Comparative reactivities of electrogenerated radical cations in cationic polymerization

Abstract

AbstractPersistent radical cations were produced electrochemically from the parent hydrocarbons 9,10‐diphenylanthracene (DPA), 9‐phenylanthracene (9‐PA), 9,10‐dimethylanthracene (DMA), rubrene (Ru), triphenylene (TP), 1,3,6,8‐tetraphenylpyrene (TPP), and perylene (P). The stabilities of these cations in the absence of monomer were equation image The rates of decay of increased with the dielectric constant of the solvent and were 4 to 5 times greater in CH3CN than in CH2Cl2 or C6H5NO2.The kinetics of the reaction of the radical cation with monomer were investigated for styrene and isobutyl vinyl ether. For styrene and or a first order dependence on the radical cation concentration was found. However, decay was unaffected by the addition of styrene and polymerization was not initiated. With and isobutyl vinyl ether a first order dependence on cation was observed and polymers were obtained.Electropolymerizations were also conducted with the generation of radical cations in situ and the rates of monomer consumption and polymer production were measured. The passage of the same electric charge in Faradays (1 Faraday=96496 coulomb) resulted in the polymerization of different amounts of the monomer and generally paralleled the reactivities found for the various radical cations.