A molecular weight–intrinsic viscosity study of several diene polymers

An intrinsic viscosity‐molecular weight study has been made of several polybutadienes and synthetic polyisoprenes. The Fox‐Flory treatment of such data was applied in each case. This serves for the determination of a constant characteristic only of the polymer and related to the unperturbed end‐to‐end distance of the polymer chain. A comparison of the dependence of this constant on polymer structure with that predicted theoretically shows good agreement. A further comparison of the values of this constant for the synthetics with those for natural polyisoprenes leads to the conclusion that the diene polymers, natural and synthetic, do not differ markedly in hindrances to free rotation.