The characteristic ratios of stereoirregular polybutadiene and polyisoprene

The characteristic ratios of stereoirregular polybutadiene and polyisoprene have been evaluated by a combination of intrinsic viscosity and light‐scattering measurements under θ conditions. The polydienes were synthesized by anionic polymerization and thus had near‐monodisperse molecular weight distributions and were of uniform microstructure. The polybutadiene C∞ was found to be 5.1, which is in good agreement with the Abe–Flory predictions. However, the value of 5.1 for polyisoprene is somewhat higher than prediced by theory.