Pressure-volume-temperature (P-V-T) properties were measured for 1-octanol + acetophenone, the polymer solutions of poly(propylene glycol) (PPG) with the mixed solvents of 1-octanol and acetophenone, and the polymer blends of poly(ethylene glycol) (PEG)/poly(ethylene glycol methyl ether) (PEGME) with anisole at temperatures from 298.15 K to 348.15 K and pressures up to 50 MPa. The Tait equation represents accurately the pressure effect on the liquid densities over the entire pressure range. The experimental-specific volumes of the constituent binary systems were correlated with the Flory-Orwoll-Vrij and the Schotte equations of state to determine the binary interaction parameters. By use of these determined binary parameters, the equations of state predicted the specific volumes to average absolute deviations of better than 0.13% for the ternary mixtures composed of PPG with the mixed solvents and the polymer blends of PEG/PEGME with anisole.