A New Strategy for Obtaining the Pc-Saft Parameters for Polymers

In this work, a parameterization strategy that allows for the estimation of polymer molecular parameters from a pre-defined set of macroscopic properties is presented. The parameterization scheme has been developed in terms of the Flory-Huggins interaction parameter,χ,and the Hildebrand parameter, δ,which are readily available in the literature for a large variety of solvents and polymers. The proposed parameterization strategy is demonstrated by reference to the PC-SAFT equation of state, but might be extended to any molecular-based model. The polymers investigated in this study include polyisobutylene, polyethylene, polypropylene, polystyrene and polybutene as well as polyisoprene and polybutadiene, for which parameters are reported for the first time in this work. The solvents studied include nonassociating compounds such as n-alkanes, polar compounds such as ethers, esters and ketones, and associating compounds such as alcohols. Phase equilibria calculations of binary polymer solutions are made to evaluate the performance of the PC-SAFT model using polymer molecular parameters calculated from the proposed parameterization strategy. The results obtained are in reasonable agreement with the available experimental data for most studied systems.