Phase behavior on the poly[octyl (meth)acrylate] + supercritical fluid solvents + monomer and CO 2 + monomer mixtures at high pressure

Abstract

Experimental cloud-point data to 220 °C and 2660 bar are reported for binary and ternary mixtures of poly(octyl acrylate) [P(OA)] + CO 2 + octyl acrylate (OA), poly(octyl methacrylate) [P(OMA)] + CO 2 + octyl methacrylate (OMA), and P(OA) + supercritical solvents systems. The cloud-point curves for the P(OA) + CO 2 + 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) + C 4 hydrocarbons cloud-point curves are ∼150 bar lower than the P(OA) + C 3 hydrocarbons curves at fixed temperature. The phase behavior for the system P(OMA) + CO 2 + 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 CO 2 + OA and CO 2 + 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.