Poly-α-methyleneglutaronitrile. Characteristic features of some anionic polymers

For (initiator)/(monomer) ratios exceeding 10^-3, the anionic polymerization of α-methyleneglutaronitrile in homogeneous solution in DMF (initiated by lithium-naphthalene at -35° or by diphenylmethyl-lithium at -70°) leads to fairly white polymers with yields higher than 75 per cent. Infra-red and u.v. spectrometric studies and flash pyrolysis experiments show that the nitrile functions are involved in the polymerization only to a very small extent. On the other hand, molecular weight and sedimentation measurements and hydrodynamic behaviour of the polymer in DMF solution suggest a broad polydispersity for the samples, and a very high branching density for their higher molecular weight fractions. These characteristic features are to be correlated with those of anionic polyacrylonitrile; they may be tentatively attributed to transfer to polymer at the acidic methylene group a to the nitrile function.