Novel Method for Estimating Pure-Component Parameters for Polymers:  Application to the PC-SAFT Equation of State

Abstract

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.

Capabilities, limitations and challenges of a simplified PC-SAFT equation of state

“…However, such parameters which require phase equilibria data for mixtures are not unique. Recently, Kouskoumvekaki et al [10] presented a method for estimating the PC-SAFT parameters of polymers without use of mixture data. The method is based on the principle of using the monomer parameters and a suitable extrapolation equation.…”

Solubility of gases and solvents in silicon polymers: molecular simulation and equation of state modeling

“…A large number of approaches have been proposed so far for SAFT-based models [5,6,16] that each seems to work well for specific cases only. In this work, sPC-SAFT calculations were PDMSM is a non-polar elastomer whose chemical structure resembles closely the structure of polyolefins.…”

“…Consequently, energetic interactions between PDMSM segments are expected to be close to those between polyolefin segments. For this reason, the ε/k value proposed previously for polyethylene [16] was used also for PDMSM. The other two parameters were fitted to the relatively few melt density data available for over a narrow temperature and pressure range and are shown in Table 5 [11].…”

“…Furthermore, sPC-SAFT is used to predict the phase equilibria of various PDMSsolvent and PDMSM -solvent mixtures. In the case of a macroscopic model, a critical issue is the protocol used for pure component and binary parameter estimation [16]. Some experimental data for the pure polymer melt and for the binary mixture are needed in order to tune model interaction parameters.…”

Phase Equilibria Calculations of Polyethylene Solutions from SAFT-Type Equations of State

“…[23][24][25][26] The modeling of polymer phase equilibria with SAFT-type equations and related approaches poses two problems: the calculation of the polymers pure component molecular parameters, due to the lack of vapor pressure in polymer melts, and the numerical problems due to the large asymmetry of polymersolvent/gas systems. The fitting of SAFT parameters for polymers is a very debated problem: 20,24 the problem is that the parameters obtained by fitting only to the density data of pure polymers provide poor descriptions of the mixtures behavior, hence lacking transferability. One of the proposed solutions was to fit the polymer parameters to a polymer binary mixture.…”