Reactivity of Vinylferrocene and Vinylcymantrene in Radical Initiated Solution Copolymerizations.

摘要

Vinylferrocene(M1) has been classified with the Q-e scheme as an exceptionally electron rich vinyl monomer from copolymerization studies with 12 vinyl organic monomers. In copolymerizations with vinylcymantrene, N-vinylcarbazole, p-N,N-dimethylaminostyrene, 1,3-butadiene, N-vinyl-2-pyrrolidone, and styrene, the value of e for vinylferrocene was consistently in the range of -2.0 to -2.6 and the Q-e scheme was applicable. The Q-e scheme failed when electron deficient comonomers such as methyl methacrylate, methyl acrylate, acrylonitrile, diethyl fumarate, fumaronitrile, and maleic anhydride were employed, presumably due to competition of the charge transfer model with the terminal model. Vinylcymantrene exhibited the same copolymerization behavior and its value of e was about -2 when using electron-rich comonomers where the Q-e scheme held. The reactivity ratios, from which values of e were calculated, were obtained using the integrated form of the copolymer equation and the proper non-linear least-squares fitting technique. The importance of this method, especially with regard to past classification of vinylferrocene by the Q-e scheme, is discussed. (Author)