Huggins' constant and unperturbed parameter of dilute polymer solutions

A novel method developed to evaluate the unperturbed parameter Kθ from the viscometric data of dilute polymer solutions can be considerably simplified by making the reasonable assumption that the Huggins' constant under theta conditions, kHθ, is equal to ½ for a number-average degree of polymerization of over about 2000. Two linear equations are derived pertaining to the present analysis, one to deal with the experimental data, and the other specially to estimate the intrinsic viscosity [η]θ which corresponds to κHθ. All calculations were done by the linear least-squares method. The Kθ was computed by the Mark–Houwink–Sakurada equation. It is shown that reliable results on Kθ can be obtained for polystyrene and poly(vinyl acetate).