Studies in cyclocopolymerization. III. Copolymerization of divinyl ether with certain nitrogen‐containing alkenes

The copolymerization of divinyl ether with fumaronitrile (A), tetracyanoethylene (B), and 4‐vinylpyridine (C) has been studied, azobisisobutyronitrile being used as initiator. The compositions of the copolymers were calculated from their nitrogen and unsaturation content. Over a wide range of initial monomer composition, the mole fraction of A in the copolymers lies in the range 0.55–0.63, and the copolymers contained only 2–3% unsaturation, indicating a high degree of cyclization. The composition of the copolymers of B indicated that cyclization occurred to only a small extent, as the copolymers contained rather high unsaturation content. The values of r1 = 0.23 and r2 = 0.12 were obtained. The mole fraction of C in the copolymers lies between 0.85 and 0.998. If the assumption is made that r1 ⋍ rc ⋍ 0 and there is predominant cyclization, r2 = 32.0 in this case. The difference in the composition of the copolymers is attributed to the difference between the electron density of the double bonds in A, B, and C.