In this work, we develop a method for estimating pure-component parameters for polymers for the PC-SAFT equation of state. Our method is based on pure-polymer PVT data and extrapolating equations that relate the polymer parameters to those of the corresponding monomer. The obtained parameters are thus unique for each polymer and do not depend on any mixture data. The new pure-component parameters are used as input in the simplified PC-SAFT equation of state, to evaluate both the parameters and the equation of state for a variety of binary polymer mixtures exhibiting both vapor-liquid and liquid-liquid phase equilibria. In most of the systems studied, very satisfactory results are obtained. Vapor-liquid and upper critical solution temperatures in liquid-liquid equilibria are accurately correlated with small values of the interaction parameter.