PHASE-EQUILIBRIA OF SATURATED AND UNSATURATED POLYISOPRENE IN SUBCRITICAL AND SUPERCRITICAL ETHANE, ETHYLENE, PROPANE, PROPYLENE, AND DIMETHYL ETHER

Cloud-point pressures were measured for binary sub- and supercritical fluid solutions of saturated or unsaturated polyisoprene (UPEP) in eth ane, ethylene, propane, propylene, and dimethyl ether up to 150 degree s C and 1,400 bar. The polyisoprene was hydrogenated to obtain two sam ples of different degrees of saturation (56% and 73%). These polymers and solvents were chosen to evaluate pi-pi interactions between polyme r/polymer or polymer/solvent molecules. pi-pi interactions between pol ymer and solvent are found to shift the cloud-point pressures in an an alogous way to those found for cross-associating polymers. Preliminary correlations using the statistical associating fluid theory (SAFT) ar e also included.