Influence of α-Olefin Concentration and Length on the High-Pressure Phase Behavior of (α-Olefin + n-Hexane + LLDPE) Systems

Abstract

Liquid to vapor–liquid, liquid–liquid to vapor–liquid–liquid, and liquid to liquid–liquid transition pressures of (α-olefin + n-hexane + LLDPE) systems were measured using a newly constructed and verified synthetic-visual high-pressure cell and metallocene linear low-density polyethylene (LLDPE: Mw = 199 kg·mol–1, Mw/Mn = 2.62, 2.56 mol % 1-hexene). New phase behavior data are reported for a quasibinary (n-hexane + LLDPE) system at polymer mass percentages of wP = (0.5–5) wt % and quasiternary (α-olefin + n-hexane + LLDPE) systems for wP = 3 wt % and polymer-free α-olefin mass percentages of up to 3 wt % ethylene, 20 wt % 1-butene, 100 wt % 1-hexene, 30 wt % 1-octene, and 30 wt % 1-decene. The reported data span temperatures of T = (380–470) K and pressures of P = (0.5–13) MPa. They show that (i) transition temperatures and pressures change linearly with α-olefin mass fraction in the solvent; (ii) the C2 to C6 α-olefins decrease, and the C8 to C10 α-olefins increase the transition temperatures; and (ii...