Free‐radical homopolymerization and copolymerization of vinylferrocene

The benzene solution homopolymerization of vinylferrocene, initiated by azobisisobutyronitrile, gave a series of benzene‐soluble homopolymers. Thus, free‐radical copolymerization studies were performed with styrene, methyl acrylate, methyl methacrylate, acrylonitrile, vinyl acetate, and isoprene in benzene. With the exception of vinyl acetate and isoprene, which did not give copolymers with vinylferrocene under these conditions, smooth production of copolymers occurred. The relative reactivity ratios, r 1 and r 2 , were obtained for vinylferrocene–styrene copolymerizations by using the curve‐fitting method for the differential form of the copolymer equation, by the Fineman‐Ross technique, and by computer fitting of the integrated form of the copolymer equations applied to higher conversion copolymerizations. In styrene (M 2 ) copolymerizations, the curve‐fitting and Fineman‐Ross methods both gave r 1 = 0.08, r 2 = 2.50, while the integration method gave r 1 = 0.097, r 2 = 2.91. Application of the integration method to methyl acrylate and methyl methacrylate (M 2 ) gave values of r 1 = 0.82, r 2 = 0.63; r 1 = 0.52, r 2 = 1.22, respectively. The curve‐fitting method gave r 1 = 0.15, r 2 = 0.16 for acrylonitrile (M 2 ) copolymerizations. From styrene copolymerizations, vinylferrocene exhibited values of Q = 0.145 and e = 0.47.