Various solution properties have been selected for testing the usefulness of the classical lattice model. The analysis leads to the inclusion of improvements such as different contact numbers for molecules and repeat units, distinction between concentration regimes, dilute and concentrated in polymer. The extensions of the simple model supply an adequate description of the data provided the free enthalpy of mixing in the concentrated region is made temperature- and molar mass-dependent. Part of the latter contribution can be attributed to the chains bending back on themselves. The other part is not easily accommodated in the model and might be related to free volume effects that have been left out of the present consideration. The resulting free enthalpy expression quantitatively covers independent data like osmotic pressure measurements by Krigbaum and binodals in near ternary systems by Hashizume et al.
Progress in Colloid and Polymer Science, Volume 71/1985.