Phase behavior on the poly[octyl (meth)acrylate] + supercritical fluid solvents + monomer and CO2 + monomer mixtures at high pressure

Experimental cloud-point data to 220 °C and 2660 bar are reported for binary and ternary mixtures of poly(octyl acrylate) [P(OA)] + CO2 + octyl acrylate (OA), poly(octyl methacrylate) [P(OMA)] + CO2 + octyl methacrylate (OMA), and P(OA) + supercritical solvents systems. The cloud-point curves for the P(OA) + CO2 + OA (or dimethyl ether (DME)) system changes the pressure–temperature (P–T) curve from upper critical solution temperature (UCST) region to lower critical solution temperature (LCST) region as the OA (or DME) concentration increases. The P(OA) + C4 hydrocarbons cloud-point curves are ∼150 bar lower than the P(OA) + C3 hydrocarbons curves at fixed temperature. The phase behavior for the system P(OMA) + CO2 + OMA are measured in changes of the P–T slope, and with cosolvent concentrations of 0–42.4 wt.%. High pressures phase behavior data are measured for the CO2 + OA and CO2 + OMA systems at the temperature range from 40 to 120 °C and pressures up to ∼208 bar. Both system exhibit type-I phase behavior with a continuous mixture-critical curve and both are adequately modeled with the Peng–Robinson equation of state.