Viscoelastic properties of branched whole polymers. II. Regularities in the solution viscosity, melt viscosity, and molecular weight

For linear polymers there is generally an experimental relation between the melt viscosity η, intrinsic viscosity [η], and viscosity‐average molecular weight M̄v, which forms a one‐dimensional curve in the three‐dimensional space, η, [η], M̄v. Thus, from a knowledge of one of these quantities it is possible to obtain the other two. For randomly branched polymers, evidence is given in this paper to show that there exists a twodimensional surface in this same space so that any one of these three variables may be obtained from a determination of the other two. In such cases the viscosity‐average weight may be obtained from a measurement of both [η] and η. Such a relationship is shown to exist from the data of Charlesby on branched silicones as well as our own data on polyolefins.