High-Pressure Phase Behavior of Poly(l -lactic acid), Trichloromethane, and Carbon Dioxide Ternary Mixture Systems

In this study, the phase behavior of a poly(l-lactic acid) (M = 312000, polydispersity 2.189)-trichloromethane-carbon dioxide ternary system was measured using a variable volume view cell at pressures up to 34.0 MPa and temperatures between (313.15 K and 363.15) K at an interval of 10 K. Bubble and cloud point pressures were determined as functions of the trichlomethane-to-carbon dioxide ratio, concentration of poly(l-lactic acid) (1.0, 2.0, and 3.0 wt %), and temperature. The hybrid equation of state for the supercritical CO₂-polymer system combined with the van der Waals one-fluid mixing rule was used for correlation of the experimental results. The three binary parameters of this system were optimized by the simplex method algorithm.