Comparison of different polymolecularity correction formulae for the burchard‐stockmayer‐fixman relationship

Abstract

Polymolecularity correction of the original and the modified procedure according to Burchard, Stockmayer and Fixman, especially useful for the determination of the unperturbed dimensions of macromolecules, is derived via the general “principle of corresponding averages” and compared with the polymolecularity correction methods published by Sutter et al. and Rosenvasser et al. It is shown that the polymolecularity correction factor to be used with the mass-average molar mass in the Burchard-Stockmayer-Fixman relationship is identical to that derived from the corresponding averages of this relationship. Numerical calculations with series of hypothetical monomolecular and polymolecular (exhibiting Schulz-Zimm distributions of the molar mass) polymer-homologous polymer samples in three different thermodynamically good solvents also demonstrate the superiority of the correction method according to Sutter et al. as compared to the correction method of Rosenvasser et al.