(663e) Solution Behavior At High Pressures: Linear to Star Polymers in SCF and Liquid Solvents

The advent of new chemistries has led to the creation of well-defined, novel polymer architectures.  These new polymeric structures have been used as surfactants, detergents, topical creams, fuel additives, and the building blocks for drug delivery, to name just a few of the potential uses.  In this talk we describe the experimental techniques used to determine the phase behavior and density behavior of linear and "star" polymers in supercritical fluid (SCF) and liquid solvents at temperatures to 250°C and 3,000 bar.  Special attention is given to the impact of the amount and length of chain branching, the functional groups in the chain, and the molecular weight of the polymer on the observed solution behavior at high pressures.  In some cases the polymers are fractionated using SCF solvents to reduce the molecular weight polydispersity.  The solvents considered in this study range from ethane, propane, and CO₂ to hexane, dodecane, and hexadecane.  The resultant phase behavior and density data are modeled using the Perturbed Chain Statistical Associating Fluid Theory (PC-SAFT).  The strengths and weaknesses of the PC-SAFT approach are presented in the talk.