(80g) Phase Behavior of Polydisperse Branched Polyolefins Using the PC-SAFT Equation of State
AIChE Spring Meeting and Global Congress on Process Safety
Tuesday, April 24, 2007 - 4:00pm to 4:20pm
The physical properties of polymeric materials can be tailored to a customer's specific needs by the choice of the R-olefin comonomer and the adjustment of its content in the chain. Processing of such polymers requires an understanding of the phase behavior as a function of comonomer content as well as polydispersity. In this work we present a simple thermodynamic model for branched polyolefin systems in the framework of the PC-SAFT equation of state. The model efficiently captures the effect of chain branching, comonomer type, and branching density on the phase behavior of polyolefin solutions. Since few adjustable parameters are required, it can be applied to systems for which little experimental data is available. The model parameters follow sensible trends, providing robustness for extrapolations and parameter prediction. We use the model to demonstrate the effect of polydispersity in molecular weight and polydispersity in comonomer content on the phase behavior of polymer solutions. Finally, the simple formulation facilitates its incorporation into commercial software for phase equilibria calculations.