Phase Behavior of the Poly[hexyl (meth)acrylate]−Supercritical Solvents−Monomer Mixtures at High Pressures

Abstract

Pressure−composition isotherms are obtained for carbon dioxide (CO2)−hexyl acrylate and CO2−hexyl methacrylate systems at 40, 60, 80, 100, and 120 °C and pressure up to 189 bar. The CO2−hexyl acrylate and CO2−hexyl methacrylate systems exhibit type I phase behavior with a continuous mixture critical curve. Three-phase, liquid−liquid−vapor equilibrium was not observed at these conditions. The experimental results for CO2−hexyl acrylate and CO2−hexyl methacrylate mixtures are modeled using the Peng−Robinson equation of state. A good fit of the data is obtained with the Peng−Robinson equation of state using two adjustable parameters for CO2−hexyl acrylate and CO2−hexyl methacrylate systems. Experimental cloud-point data to 200 °C and 2200 bar are measured for binary and ternary mixtures of poly(hexyl acrylate)−CO2−hexyl acrylate and poly(hexyl methacrylate)−CO2−hexyl methacrylate systems. Also, the cloud-point curves show the binary mixtures for poly(hexyl acrylate) in supercritical ethylene, propane, propyl...