On the Thermodynamic Properties of Solutions of Polar Polymers. A Comparison of Experiment and Theory

Abstract

In this paper we present a comparison of experimental and theoretical studies of the thermodynamic properties of solutions of polar polymers. In particular: (a) A new method of achieving isopiestic equilibruim is described in detail. (b) The excess free energies of solutions of toluene with poly-p-methylstyrene, poly-p-bromostyrene and several copolymers of p-methyl and p-bromostyrene are reported and analyzed. (c) The continuum model of concentrated solutions of polar polymers presented in the preceding paper is shown to be accurate for φ1>0.4, for the polymers studied. (d) The perturbation theory of dilute solutions of polar polymers presented in the preceding paper is shown to predict the proper behavior in the limit of zero polymer concentration. (e) The properties of copolymers with small skeletal concentration of polar subunits is shown to agree with the predictions of the perturbation theory presented in the preceding paper. (f) The fundamental assumption of the continuum theory concerning the relationship between dipolar orientation and chain connectivity is examined and shown to agree with experiment. (g) Deviations between theory and experiment are briefly discussed in terms of the basic assumptions of the model, and methods by which the theory can be improved are described.