High-pressure phase equilibria in the system linear low density polyethylene + isohexane: Experimental results and modelling

High-pressure phase equilibrium data were measured for the system linear low density polyethylene (LLDPE) + isohexane. The LLDPE sample was a hydrogenated polybutadiene (hPBD) and was nearly monodisperse ( M w / M n = 1.19 ) . Phase transitions were observed visually using a Cailletet apparatus for mixtures with polymer mass fractions from 0 to 0.25 at temperatures from 380 to 500 K and pressures up to 12 MPa. Cloud points, bubble points and three-phase liquid–liquid bubble points were measured. The data were modeled using the modified Sanchez–Lacombe (MSL) equation of state. Results are compared with data and model calculations for the same LLDPE with n-hexane.