POLYMER-SOLUTIONS WITH SPECIFIC INTERACTIONS - EQUATION OF STATE FOR POLY(4-HYDROXYSTYRENE) PLUS ACETONE

We have obtained the p-V-T surface of the mixture acetone + poly(4-hyd roxystyrene) over the intervals 298 less-than-or-equal-to T/K less-tha n-or-equal-to 328, 0 less-than-or-equal-to p/MPa less-than-or-equal-to 40, and 0.45 less-than-or-equal-to w less-than-or-equal-to 0.97, w be ing the weight fraction of acetone. The results obey a p-T-w superposi tion principle, making it possible to build a master curve when the pr essure and the density are reduced with the isothermal compressibility and the density is at a reference pressure, respectively. The master curve depends on a single system-dependent parameter, which takes simi lar values for quite different mixtures. The master curve allows us to describe the pressure dependence of the density within experimental u ncertainty. The bulk modulus of the system can be described quite accu rately using a correlation inspired by a perturbation theory which ass umes a spherical reference system. The data have been analyzed with tw o versions of a lattice-fluid model. One of the versions includes, in an approximated way, the existence of hydrogen bonds, both in the poly mer and between the polymer and the solvent. However, almost no differ ence is found between the predictive ability of the two versions, at l east for the p-V-T-w surface.