Determination of branching in a randomly branched polydisperse polymer

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Abstract
Methods are presented for the determination of degree of branching in a randomly branched polymer with tetrafunctional branch units. Typical examples of such polymers are irradiated linear polymers and copolymers of divinyl and monovinyl monomers. The most practicable method is found to be the comparison of the intrinsic viscosity of the branched polymer to the intrinsic viscosity of the corresponding linear polymer of the same weight‐average molecular weight. Agreement is found with previously published experimental data on polymers of known degrees of branching. It is also found that the ratio of the mean square radius to the weight‐average molecular weight for the polydisperse branched polymer is completely independent of degree of branching. Consequently, light‐scattering data alone on the polydisperse polymer is not sufficient to determine branching.