Phase‐separation phenomena in solutions of poly(2,6‐dimethyl‐1,4‐phenylene oxide). I. Thermodynamic parameters of solutions in toluene

New experimental data have been collected on thermodynamic properties of solutions of poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) in toluene. The Flory–Huggins interaction parameters g have been determined from light scattering measurements. These values are in agreement with values obtained by osmotic measurements at low concentrations and they allow the calculation of a melting point curve which fits the experimental melting points. No liquid–liquid phase separation can be calculated, as was concluded in a preceding paper. Spinodals could not be detected by light scattering or DSC‐measurements. This also indicates that liquid–liquid phase separation does not occur. The phase separation on cooling of a PPO‐toluene solution is thus believed to be a crystallization phenomenon.